TABLE OF CONTENTS
Charge Questions to the Committee and Committee Responses in Brief
Responses to Charge Question 1
Responses to Charge Question 2
Responses to Charge Question 3
Responses to Charge Question 4
Responses to Charge Question 5
Responses to Charge Question 6
Responses to Charge Question 7
Responses to Charge Question 8
Water is an essential part of food animal processing, and current processing practices use large volumes of water. Due to climate change, the food industry's access to clean and inexpensive water is increasingly a challenge. The U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) seeks evaluation by the National Advisory Committee on Microbiological Criteria for Food (NACMCF) to facilitate the safe reuse of sources of water in order to reduce water consumption.
CHARGE QUESTIONS TO THE COMMITTEE AND COMMITTEE RESPONSES IN BRIEF
FSIS requests guidance from the NACMCF to address alternatives to current water usage practices, guidelines, and regulations for FSIS-regulated products to help clarify the following issues.
Charge Question 1
What are the current water usage practices for slaughterhouses and processors? At which steps might water conservation or alternative water sources be feasible?
Summary, recommendations. There is a large variability, such as processing practices for each animal, practices within the same animal species, etc., in the application of water in food animal processing. There are a limited number of publications on water use by species. The industry may have some information that is not publicly available. Important gaps are the lack of information for pork and channel catfish processing. Water management strategies should include water conservation practices, which are low-cost practices that may result in important reductions in water usage. The 2020 COVID-19 pandemic may have a large impact on the increase of water usage, specifically related to the implementation of more stringent cleaning and sanitation practices in meat and poultry processing establishments. There should be more collaboration among stakeholders (e.g., industry, academia, government) to collect missing information on water usage and opportunities for reuse.
Charge Question 2
What are the available technological strategies for water reuse, recycling, reconditioning, and reclamation, and how might FSIS-regulated facilities use them? Is a fully closed water system reasonable as a goal?
Summary, recommendations. Many factors influence the type of wastewater treatment methods that an establishment can implement, including the local cost of water and the cost of the technology. There are already examples of water reuse in a counterflow direction to the movement of product, such as the counterflow scalders and chillers used for the processing of chickens. Water conservation, based on judicious use of water and changes in behavior, is an important starting point to reduce the overall water usage. A complete understanding of energy use and plant infrastructure limitations is necessary to effectively understand all opportunities for water conservation and recycling.
Charge Question 3
Water contaminants can be microbiological, chemical, toxicological, physical, and nutrient in nature. Identify these contaminants and how their presence and concentrations in potable water (municipal and from wells) compare to those found in water treated using the reuse, recycling, reconditioning, and reclamation technologies identified in Question 2 above. Identify the risks posed by these contaminants for various steps in food production and processing.
Summary, recommendations. Characterization of microbial and chemical contaminants in water is a very large topic that requires extensive work. There are quality standards for potable water but not for the recycled water from different processing states and different water treatment systems. Different treatments may deal with different contaminants. Thus, a comparison of potable water versus reused, recycled, or reconditioned water is not easy to address. As we move to fit-for-purpose water recycling and usage, quality standards may need to be developed for each application and recycling system.
Charge Question 4
How do residual contaminants in water used for animal production, slaughter, and processing affect product quality and safety? What are the quality implications and public health risks associated with contaminants at levels anticipated for reconditioned water? How might FSIS and industry best assess those implications and risks? How do residual contaminants in water affect the functions of various materials added to water used in all stages of food production and processing, such as feeds, medicines, and antimicrobials? For example, consider the effects of trace pharmaceuticals on animal husbandry and the effects of iron and “hard water” on phosphate-based interventions.
Summary, recommendations. The distinction of two water quality standards, one for water that has direct or indirect contact with food and one for water that has no contact with food, best assures safety. FSIS and industry can use a fit-for-purpose risk assessment approach to assess public health risks from water reuse in food contact applications that do not already require potable water quality and make the risk assessment adaptable to the specific food and use situations. Reused water in animal processing should be evaluated to ensure that the finished products do not exhibit an increase (relative to current water usage practices) the health risks associated with these products. A uniform standard for and federal regulation of the quality of reused or recycled water in FSIS-regulated facilities is needed. Currently, local authorities using highly variable criteria determine both the water standards and regulations.
Charge Question 5
What are the best ways to assure and/or monitor the quality and safety of alternatively sourced water used in FSIS-regulated operations?
Summary, recommendations. There are physical, chemical, and microbiological parameters that have been traditionally monitored to assess water quality. Standard water analysis methods are available, well developed, and reliable. Initial monitoring of alternatively sourced water should be extensive, while ongoing performance monitoring should be conducted in real time and focus on measuring indicators (refer to Glossary). Water for nonfood contact uses will require monitoring of fewer parameters. The set of quality parameters to be tested and the testing frequency should be developed for each technology and application based on the contaminants of concern and those that the technology will reduce or remove. This set of quality parameters could include indicators of water quality for each food animal species, for different areas in processing, and for the processing areas where reprocessed water will be used.
Charge Question 6
Are there special considerations for foods that are produced entirely within water (e.g., fish), and if so, what are they?
Summary, recommendations. Maintaining good water condition in fishponds is essential to control fish diseases and to provide adequate production of channel catfish. Some water conservation strategies have been published for fish processing establishments; however, economic and other incentives to incorporate conservation practices or recycling technologies do not exist.
Charge Question 7
Flooding can contaminate animals and water sources with human sewage and farm waste. What precautions should establishments take when floodwater or runoff affects a food or water source or a processing area?
Summary, recommendations. Companies should develop emergency programs to manage natural disasters, such as flooding. There are several national and state guidelines that can be reviewed for the organization of these emergency programs.
Charge Question 8
What technologies are appropriate for the replacement of liquid water in food production and food processing areas (e.g., foam, mist, or dry chemicals)? What advanced emerging technologies may reduce the need for or volume of water in processing?
Summary, recommendations. Conducting a review of cleaning and sanitation and other manufacturing practices and the use of alternative technologies, such as air chilling instead of water chilling, helps in the identification of areas in which changes could contribute to an overall reduction of water use in a processing establishment. Newer technologies (e.g., ozone generators, UV treatments, and surface coatings with sustained antimicrobial properties) are being approved by the U.S. Environmental Protection Agency (EPA) for specific sanitation practices and may provide viable alternatives to reduce water usage during the cleaning and sanitizing practices in animal food establishments.
Current FSIS regulations on the use of water during the processing of meat and poultry products were last updated in the 1990s and may not account for the most recent technologies or alternatives to water use. Water requirements for establishments slaughtering and processing meat and poultry products are covered in the sanitation regulations in the Code of Federal Regulations (CFR) 9 CFR 416.2(g)(1), (2), (3), (4), (5), and (6) (72). The water used in food processing must comply with 40 CFR 141, the National Primary Drinking Water regulations, when a municipal water supply is used. When a private well is used, food processors must make available to FSIS documentation certifying the water's potability. Regulation 9 CFR 416.2(g)(4) limits the use of reconditioned water and may not reflect current technological capabilities of water treatment. Climate change is challenging the food industry's access to clean and inexpensive water. The frequency, severity, duration, and location of weather and climate phenomena (i.e., rising temperatures, flooding rains, and droughts) are changing, which will continue to impact the food industry's ability to produce safe food. It is essential that regulatory agencies assess these changes and evaluate current regulatory requirements associated with water use. They must also be able to provide alternatives to current water consumption practices that allow industry to use less and recycle more water through developing criteria on the appropriate uses of water sources in the processing of food.
RESPONSES TO CHARGE QUESTION 1
1. What are the current water usage practices for slaughterhouses and processors? At which steps might water conservation or alternative water sources be feasible?
There is large variability in the application of water in food animal processing. This variability includes differences in the processing practices for each animal species (beef, pork, poultry, and channel catfish) and variations within the practices employed within the same animal species. Other factors that affect water usage practices include the available and implemented technologies at the establishments, the equipment and practices in place, education and training on water conservation (refer to Glossary), and the actual cost and benefits of water conservation, recycling, and reuse (refer to Glossary) for each establishment. However, there is limited information on the exact water use at each of the different processing steps and for the different food animal establishments in the United States (27, 52). There is also limited information on the costs and benefits of each of the available water conservation, recycling, and reuse technologies.
In general, meat processing may account for up to 24% of freshwater consumption in the food and beverage industries, and seafood accounts for approximately 2% (19). A report from Australia estimated that the water usage in beef slaughter establishments varied from 3.8 to 17.9 kL/ton of carcass weight produced (96).
Table 1 describes the estimated amounts of water used during the processing of broiler chickens, beef, and turkeys. Although there are several reports on the use of water in establishments processing broiler chickens and beef, there is less information about establishments processing turkeys, pork, and channel catfish. Most of the published studies about water use in beef are from countries other than the United States.
The potential costs and benefits for water reuse or recycling projects may result in an increased efficiency by the establishment, with energy savings and more efficient use of antimicrobial applications. A complete understanding of energy cost and plant infrastructure limitations is important to effectively understand all opportunities for water conservation and recycling.
The water usage in broiler processing is described in Table 2. Poultry harvest facilities rely primarily on water to drop the temperature of the carcasses postevisceration and to deliver antimicrobials to control bacterial pathogens. For broiler chickens and turkeys, water chillers are as large as 200,000 gal (909,218 L). The major water usage occurs in the areas from evisceration to carcass chilling. In each of these areas, there are opportunities for water conservation. In some cases, the industry has reused water (refer to Glossary) from the end of the chill tanks to feed the scalding tanks (5, 15, 47, 59, 62).
In a study conducted in a broiler processing plant in Brazil (5) with a water supply consisting of 99.5% from deep water wells and 0.5% from a public water supply system, the proposals for water consumption reduction included
• reusing effluent from cleaning of transport cages (after removing coarse solids) would result in reductions of
12% of potable water consumed
1% of the effluent generated;
• reusing effluents generated by the cooling towers and in the defreeze of cooling tunnel and storage chambers; 7.5 and 1.4% of wastewater (refer to Glossary) generated, respectively; washing live poultry receiving and unloading yards would result in reductions of
91% of potable water consumed
7% of the slaughterhouse's overall water consumption
9% of the effluent generated;
• reusing effluent from the final rinsing of the slaughterhouse cleaning process to prewash the by-product room would result in a 4% reduction in overall water consumption.
• Using all three of the proposals listed above would result in
a reduction of about 12% of the water taken from the deep water well
a reduction of approximately 10% in the effluent generated
a savings of approximately US$6,500 per year in wastewater treatment costs.
These authors also highlighted that the incorporation of automatic, pressure-activated closing water taps could save approximately 40% of water compared with conventional taps and that incorporating an infrared device for opening and closing of taps would save an additional 30% of water usage (5).
Table 3 describes the estimated water usage in a beef processing facility. A review from an Australian beef processing facility highlights that water conservation can save up to 10% of the water usage in a small town (61). Water reuse, which is described by these authors as the “reuse of one process waste stream to the same or another process with or without pre-treatment,” could save up to 15% of a town's water usage. The publication also highlights that in small towns, the recycling of nonpotable water can save up to 40% of town water use, with a recovery on the investment within 6 to 10 years. The recycling of potable water (refer to Glossary) can save up to 70% of town water use, with a recovery on the investment of about 10 years. The calculated payback time of implementing these practices ranged from immediate to up to 3 years (61). Yet, some water reuse technologies may not be practical or economically feasible for small slaughter establishments.
In pork and beef harvest establishments, carcasses are chilled primarily by air chilling. However, water spray chill systems are also used throughout the pork and beef industries. Because the skin is not removed in the initial steps in pork processing, various methods of carcass scalding are used to remove hair follicles and wash the carcass. This can be done via large scald tanks or can be accomplished using other technologies, such as steam through vertical scalding units.
There are no publicly available data on the use of water in channel catfish processing. There are advantages in improving water management, and there are several companies providing water conservation consulting services to the food industry. Most of these companies collect background information on water usage in an animal food processing establishment by performing water audits, which can help create a water management plan to better understand the total water consumption and discharge and identify inefficient or unnecessary uses, such as taps that are left on overnight. By applying a checklist of good practices and systematically metering and tracking the volume of water used in a facility, an establishment can help to identify areas for potential water conservation (67). Table 4 shows the areas of a processing environment where there is potential for conservation and savings.
RESPONSES TO CHARGE QUESTION 2
2. What are the available technological strategies for water reuse, recycling, reconditioning, and reclamation, and how might FSIS-regulated facilities use them? Is a fully closed water system reasonable as a goal?
Factors That Determine the Choice of Technology
Water is a necessary component for meat production and meat processing. Water serves an important role in product formulations, processing, sanitation, and food safety. However, considerations for technology used for wastewater treatment methods and the ability to reuse and/or recycle are plant specific. These abilities are based upon the primary function and the infrastructure of the plant, the efficiency and cost of implementing these strategies, and regulatory requirements for both water end use and effluent.
Animal Harvest and Raw Processing
Water is vital in providing safe and wholesome food products of animal origin. The recognition of food safety and the removal of pathogens during meat processing has required the use of antimicrobials for removing microbial contamination from surfaces to be used throughout the harvest process. These surface antimicrobials are often diluted processing aids that are effective for eliminating pathogens but also have the least organoleptic effect on the quality of the meat. The reliance on and need for these surface antimicrobials will continue as standards for food safety increase.
A few opportunities for water reuse present themselves in the harvest process across all animal protein establishments. In general, water that is the cleanest and least contaminated should be used after the evisceration process. However, considerations for water quality, as it relates to food safety, will need to be evaluated to determine opportunities for reuse. An example of a potential scheme for the utilization of reused water in a turkey harvest operation could be the use of water in a flow direction counter to the movement of product: chiller water → final bird wash → first bird wash → feather wash → cage wash.
Larger scale capital projects would need to be evaluated on the basis of their merits and overall cost. An example of water usage reduction would be a pork processing plant considering a change from water spray chilling carcasses to utilization of a mechanical process of chilling, such as blast chilling. The water usage from spray chilling would need to be assessed against the increased overall energy usage from blast chilling to determine if there is a net environmental benefit, an assessment for a potential opportunity to reuse the water used in a different application further upstream in the process, as well as a financial net present value gained by making the change.
Ready-to-Eat and Further Processing
The water usage in further processing facilities should also be considered. Like harvest and raw processing facilities, water is used for sanitation, to deliver ingredients in formulation, and to improve food safety. Many of the ingredients delivered with water are vital to the functionality, identity, palatability, and safety of the product. Food additives such as salt, sugar, sodium nitrite, and antimicrobials are carried into the product via a brine. Thus, potable water is the minimum standard of acceptance for use in formulations.
Sanitation and Plant Design
Wet cleaning (refer to Glossary) sanitation is also widely employed throughout the meat processing industry. Reduction of water use may not be practical because of its importance in cleaning and sanitizing processing lines. However, opportunities for water reuse in a flow direction counter to the movement of product could be used. An example of this would be using water from the final bird wash upstream in the process, such as in the feather wash or cage wash, for the trailers used to transport the live birds. Due to the nature of the processes and the types of contaminants present, there are fewer opportunities for dry sanitation in the meat processing establishments. Because meat is an excellent growth medium for many bacteria (including pathogens), wet sanitation is also required to provide processing “breaks” in production and a sanitation schedule that reduces pathogens and spoilage bacteria. Cleaning and sanitizing protocols also limit the extent of the compromised product, should the product become contaminated with a known pathogen that results in a product recall. Extended product runs to reduce the frequency of sanitation are often product specific and need to be monitored and verified to show effectiveness with respect to food safety requirements (72).
Besides water usage implications, there are other potential meat quality, food safety, and cost implications that need to be considered if changes to water usage practices are to be considered. Many of the processing plants in the United States were built before many environmental conservation practices were envisioned and included within the building design. Thus, electrical, plumbing, and sewage requirements may present cost barriers that are difficult to overcome. Also, the ability to utilize reused and/or recycled water (refer to Glossary) may require space that may not be available in older processing plants without major renovation or construction at the facility. Inline treatment systems and the need for holding tanks may limit a plant's ability to utilize reused or recycled water in the current footprint of the plant.
Existing New Technologies for Wastewater
The U.S. EPA (83) has established effluent guidelines to comply with national standards for industrial wastewater discharges to surface waters and publicly owned treatment works (e.g., municipal sewage treatment plants). The effluent guidelines are issued for different industrial sectors under Title III of the Clean Water Act. The standards are technology based (i.e., they are based on the performance of treatment and control technologies) and not risk based or based on impact studies. The standards for wastewater discharges from meat and poultry processing are codified under 40 CFR 432 (83) and include the discharge limits for several parameters or indices, including pH, fecal coliforms (refer to Glossary), total recoverable oil and grease, 5-day biochemical oxygen demand (BOD5; refer to Glossary), and total suspended solids. Some of these indices provide information on the degree of organic pollution of the water.
Bustillo-Lecompte and Mehrvar (19) reviewed different slaughter wastewater treatment methods. Following is a brief discussion of those different methods.
Land application. Land application refers to the direct application of biodegradable materials to soil, which can help increase the nutrient content of the soil. One significant advantage of this process is the recovery of by-products from slaughter wastewater that can be used as an alternative source of fertilizer. The land application process can also improve the structure of the receiving soil. One limitation of land application is that the process is dependent on factors such as temperature and weather conditions. Hence, land application finds limited use in countries that experience very low temperatures during the winter season. Some other limitations of land application include potential surface water pollution, presence of persistent pathogens, and off-odors (10, 42, 55, 63).
Physicochemical treatment. During the slaughtering process, slaughterhouse wastewater (SWW) is separated into different components (primarily solids and liquids) using different types of methods (3, 31): (i) dissolved air filtration (DAF), (ii) coagulation and flocculation, (iii) electrocoagulation, and (iv) membrane technology.
• DAF. These systems utilize air to separate liquids and solids in SWW. The separation of solids and liquids is achieved via introduction of air from the bottom of the holding vessel. As a result, low density materials such as fat, grease, and light solids will migrate to the top of the surface forming a “sludge blanket.” This sludge blanket will then subsequently be removed. Advantages of this system are improvements in chemical oxygen demand (COD; refer to Glossary) and BOD. In addition, this system is also successful in removal of nutrients from SWW. Some limitations noted in previous studies include regular malfunctioning of the system and poor total solids removal (3, 31).
• Coagulation and flocculation. This process involves the addition of coagulants such as aluminum sulfate, ferric chloride, or ferric sulfate to treat SWW. Studies showed that these systems can significantly reduce the total phosphorous, total nitrogen, and COD during SWW treatments using polyaluminum chloride as reagents (1, 60).
• Electrocoagulation. Electrocoagulation is a cost-effective technology that has been demonstrated to be successful for separating solid and liquid waste in SWW systems. In addition, the system was proven to be effective for removing organics, nutrients, heavy metals, and even pathogens from SWW without the involvement of chemicals (32, 43).
• Membrane technology. Membrane technology, which includes technologies such as reverse osmosis, nanofiltration, ultrafiltration, and microfiltration, is very effective for removing particulates, colloids, and macromolecules based on pore size. Limitations of this process include a reliance on additional conventional technology to efficiently remove nutrients and the potential to cause fouling due to the highly concentrated SWW feeding streams (2, 19).
Biological treatment. Biological treatment involves treating SWW systems with microorganisms for the purpose of removing organic material. There are two main types of biological treatments described in literature: anaerobic and aerobic systems (19, 45, 46, 56).
• Anaerobic treatment. It is commonly perceived that anaerobic systems are less complex to operate compared with aerobic systems because they do not require complex equipment and constant aeration. Bacteria metabolize organic compounds and produce products such as carbon dioxide and methane during the anaerobic digestion process. There are several advantages to using anaerobic treatment systems: high COD removal, low sludge production compared with aerobic systems, and less energy requirements with potential generation of nutrients and biogas. One of the limitations of anaerobic treatment is it may produce effluents that do not comply with current discharge limits and standards. Specifically, when SWW systems are subjected to anaerobic treatments, stabilization of organic compounds may not be achieved owing to the organic strength of SWW.
• Aerobic treatment. In aerobic systems, bacteria metabolize organic compounds in the presence of oxygen to facilitate removal of these compounds. The strength of SWW becomes a determining factor in understanding the amount of oxygen required during the treatment of SWW systems. Typically, aerobic treatment is used following the treatment of organic compounds with a physicochemical method. In other words, it may serve as a final decontamination technology in the treatment of SWW. Aerobic reactors may have several configurations based on the amount of nitrogen required to be removed. Typical configurations for SWW aerobic treatment include activated sludge, rotating biological contactors, and aerobic sequencing batch reactors (refer to Glossary).
AOPs. Advanced oxidation processes (AOPs) are an interesting alternative to conventional treatment and a complementary treatment option, as either pretreatment or posttreatment, to current biological processes. Furthermore, AOPs do not involve the application of chemicals to inactivate microorganisms compared with the conventional systems (e.g., chlorination used for water disinfection [refer to Glossary] may have the potential to produce hazardous by-products). As a result, AOPs have been recognized as processes that can offer advanced degradation, water reuse, and pollution control, thus being positioned as an effective complementary treatment. Several types of advanced oxidation process systems have been described in the literature, including (but not limited to) ozonation, gamma radiation, and a UV light–hydrogen peroxide application (19, 50, 51, 65, 94).
Feasibility of a Fully Closed System
Establishments simply cannot operate without water. There are some system-wide reasons to recycle water.
Inherent energy cost. It is costly to get water out of the ground (or other sources), treat it to potable standards, transport it to a facility, and then properly dispose of the wastewater by treating to effluent standards and discharging back to the environment.
Competition for available water. As water becomes scarce, companies, especially those located in proximity to or in metropolitan areas, will have to compete with municipalities.
Social responsibilities. With increased attention to sustainability, the industry will want to ensure that their water use is judicious.
Once companies consider all the above and other issues that may affect their access to water, they will begin to recognize the significance of the business security that water recycling will bring to their operation and realize the importance of this financial investment.
Obstacles to water recycling.
1. Outdated policies
2. Lack of national standards, with current regulations under the jurisdictions of states and counties. Federal policies may be needed to increase consistency of water recycling in all 50 states.
Example Establishment: Harmony Beef, Calgary, Alberta, Canada
Water Recycling System Manufacturer: Delco Water, Saskatoon, Saskatchewan, Canada S7P 0A6 (https://www.delco-water.com/delco-water-projects/harmony-beef/)
Storyline. A plant that was shut down for 7 years was purchased and renovated, and when the time came to go on-line, the plant owners were told that their water allotment had been allocated to a shopping mall. The owners had to find a solution, and they focused on a water recycling system. After an extensive worldwide search, they settled on a system designed and installed by Sapphire. They are the first food processing plant in North America to reprocess their water. They recycle all process water except that in the human waste stream. More than 90% of their daily water needs are met with recycled water. The final discharge to the sewer is only 7% of the process water volume, with the rest lost to evaporation (95).
The process. The Harmony Beef system is a continuous system with a flow rate of 13.9 L/s.
1. Mechanical treatment. Water flows through a drum screen with 1-mm slot openings to remove coarse particles and large suspended solids.
2. Primary treatment. An inline analyzer is used to adjust the pH to 5.8 to 6.7, and DAF (refer to Glossary) is used to remove medium to fine particles, grit, fat, oil, and grease. This removal is achieved by dissolving air in the water or wastewater under pressure and then releasing the air at atmospheric pressure in a flotation tank basin. The released air forms tiny bubbles that adhere to the suspended matter, causing the this matter to float to the surface of the water where it may then be removed by a skimming device.
3. Secondary treatment. With this aerobic digester system, water is pumped to another tank with a moving bed biofilm reactor (MBBR; refer to Glossary), which is an attached growth biological treatment process. Prior to MBBR, inline analyzers adjust the pH to 6.8 to 7.2.
4. Tertiary filtration. Membrane ultrafiltration is used to remove emulsified oils, small suspended solids, and larger molecules from the flow.
5. Polishing. Water flows through dual reverse osmosis (RO) membrane to remove total dissolved solids, pesticides, cysts, bacteria, and viruses. Utilizing a two-pass design minimizes wastewater disposal from the treatment process.
6. Disinfection. Water is subjected to UV filtration and then chlorinated to 1 to 2%.
7. Pumping. Disinfected water is pumped to a 500,000-gal (2,273,045-L) tank ready for use.
8. Sludge treatment. The sludge moves through a dewatering process to reduce sludge volume by 60 to 70%.
Water quality. Actual data from the Certificate of Analysis (CoA) issued by Element (Calgary, Alberta, Canada) for Harmony Beef are listed in Table 5. Examination of a number of such CoAs indicates very little variability. Advantages of this recycling system include (i) no reliance on municipalities for water; (ii) no competition with human uses for water; (iii) far better quality of water than municipal or well water; (iv) 3 to 4 years to pay back; (v) no need for lagoons; and (vi) no incoming water or wastewater fees.
RESPONSES TO CHARGE QUESTION 3
3. Water contaminants can be microbiological, chemical, toxicological, physical, and nutrient in nature. Identify these contaminants and how their presence and concentrations in potable water (municipal and from wells) compare with those found in water treated using the reuse, recycling, reconditioning, and reclamation technologies identified in Question 2 above. Identify the risks posed by these contaminants for various steps in food production and processing.
This specific charge question was found to be a large topic to cover, with extensive variations due to the many different factors, including
• animal species processed,
• stage of processing at which water is used,
• contaminant under study,
• sensitivity of the methodology used to detect the target contaminant, and
• system used to produce reused, recycled, or reconditioned water (refer to Glossary).
There is limited information detailing all the potential contaminants (refer to Glossary), mainly chemical and biological, that can be present in the water used during processing. Yet, it could be assumed that all known contaminants of public health concern that have been identified by species (e.g., Campylobacter spp. in broiler chickens or Escherichia coli O157:H7 in beef) could end up in processed water in an establishment processing that species. It is also important to remember that water potability relates to drinking water standards and is determined mainly by testing for chemicals and indicator coliform bacteria, not by testing for pathogenic bacteria per se.
Studies of drinking and recreational water have generated a large volume of information on risk-based water quality thresholds for different water quality indicators using quantitative microbial risk assessment (refer to Glossary). The presence of fecal indicator bacteria (FIB; fecal coliforms or enterococci) usually is correlated with adverse health effects and is used as a water quality criterion in regulations aimed at protecting public health (84). Yet, human fecal indicator bacteria, not just all FIB, are now accepted as the most important indicator of ambient water contamination (17). We do not have similar information on the most appropriate indicators for water recycling in food animal processing establishments (refer to answers for Charge Question 5).
Nature of the Contaminants
Water used in establishments processing animal protein contains high amounts of organic matter, pathogenic and nonpathogenic microorganisms, and residual chemicals from cleaning and sanitizing activities (19, 30, 46). An essential aspect of food safety efforts in meat, poultry, channel catfish, and egg products are the monitoring and control of chemical residues that may result from the use of animal drugs and pesticides or from incidents involving environmental contaminants. The chemical contaminants coming with live animals raised with proper husbandry practices should not bring any public health concern. These contaminants include chemical compounds added to the animal feed during production, such as growth promoters and antibiotics to control animal disease.
There are specific regulations on the use and application of drugs in food production animals. These regulations establish withdrawal times for chemical compounds that need time to clear from the animal or be reduced to levels that do not represent human health concerns. The USDA FSIS administers the U.S. National Residue Program (NRP) for meat, poultry, and egg products. The NRP is an interagency program designed to identify, prioritize, and analyze veterinary drugs, pesticides, and environmental contaminants in meat, poultry, and egg products. The FSIS partners with the U.S. Food and Drug Administration (FDA) and the EPA as the primary federal agencies that manage the NRP. The FDA, under the Federal Food, Drug, and Cosmetic Act (FFDCA), establishes tolerances for veterinary drugs and action levels for food additives and environmental contaminants and reviews violative residues reported to the FDA by the USDA FSIS for risk-based inspection and compliance follow-up. The EPA, under the FFDCA, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and the Toxic Substances Control Act, establishes tolerances for registered pesticides. Title 21 CFR includes tolerance levels established by the FDA (92), and Title 40 CFR includes tolerance levels established by the EPA.
The FSIS publishes NRP data (traditionally known as the Red Book) each year to summarize the results of testing meat, poultry, and egg products for chemical residues and contaminants of public health concern. When testing for residues in food animal tissues, test results reported by FSIS laboratories are compared with a quantitative acceptable level (i.e., tolerance or action level) to verify that the meat, poultry, and egg products tested are safe and wholesome and do not contain concentrations of a chemical that would render the product adulterated.
The NRP domestic sampling program comprises two correlated programs: the scheduled sampling program and the inspector-generated sampling program. Under the inspector-generated sampling plan, the number of samples screened and collected has remained the same (fiscal year 2016 to 2019), at approximately 174,000 samples screened per year (78). The violation rate has remained below 0.4% and has declined since 2016. The predominant violative residues in the samples were antibiotics, mainly ceftiofur, penicillin, and sulfadimethoxine, which accounted for 30, 23, and 9.7% of total violative residues, respectively. Of the violations reported, 85% were attributed to cattle; dairy cows accounted for 71%, and bob veal accounted for 14%. In samples from swine slaughter (market swine, sows, roaster swine, boar swine, and feral swine), there were only eight violative samples, which represented 0.03% of the swine samples (78). The drugs in violations are mainly antibiotics found at higher than allowable levels. Thus, unless we consider the potential adverse reaction to an antibiotic (e.g., penicillin), these antibiotics are not per se a direct human health hazard.
Chemical Contaminants, Including Chemical Sanitizers
There is a potential for chemicals for sanitation practices to contaminate water used in animal food processing plants, but there is no information on the impact of the accumulation of these residual chemical sanitizers (refer to Glossary) or their by-products on the efficacy of the recycling technologies. In addition, there is limited information on the cost to remove all sanitizer from contaminated water in an animal food processing establishment. It is not clear whether interactions among different chemical compounds may bring challenges with water recycling systems. Thus, this is an area where more information is needed.
The chemical compounds used to control pathogens during the processing of food animals and that have contact with food have all received approval by the FDA as generally recognized as safe (GRAS; refer to Glossary) or as a secondary direct food additive permitted in food for human consumption (92), more specifically as an “antimicrobial agent” (refer to Glossary). These antimicrobial agents are considered processing aids with temporary technical effect in the treated food and are ordinarily removed or not present in the final food. Thus, any residuals that may be carried over to the final product are not expected to have any effect on the final product. Through the shared ingredient approval process by the two agencies, the USDA FSIS makes judgments on a case-by-case basis using the FDA's approval of a compound to determine whether a substance is a processing aid and can be used as an antimicrobial agent or is an ingredient of a food. Although the USDA FSIS determines the suitability and effectiveness for the intended purpose of use, the FSIS also ensures that the conditions of use do not result in an adulterated product. Once the suitability and safety of a compound has been determined, the substance is added to FSIS Directive 7120.1 (80). The USDA FSIS (81) also maintains a list of safe and suitable ingredients that is periodically updated. Although there is no information on the residues of “antimicrobial agents” (GRAS or secondary direct food additives) in processing water, the probability of any accumulation of these substances in their active forms in water is low.
Under regulations codified as 9 CFR 416 regarding sanitation, establishments under the jurisdiction of the USDA FSIS are required to implement and monitor written sanitation standard operating procedures (SOPs) and maintain daily records to document the implementation and monitoring of the sanitation SOPs and any corrective action taken (71). Under 9 CFR 416.4(c), the regulations require that cleaning compounds, sanitizing agents, processing aids, and other chemicals used by an establishment must be safe and effective under the conditions of use. Such chemicals must be used, handled, and stored in a manner that will not adulterate product or create insanitary conditions. Documentation substantiating the safety of a chemical's use in a food processing environment must be available to FSIS inspection program employees for review.
Companies selling cleaning and sanitizing agents must sell only compounds that have been approved for these activities and are registered as antimicrobial pesticides with the EPA under the FIFRA.
Within the food commodities under the USDA FSIS, processed eggs and siluriform fish are considered allergens. Therefore, establishments that need to reduce these allergenic proteins from surfaces to avoid cross-contact will also have to establish cleaning and sanitation protocols that are specific for these circumstances.
Biological contaminants are present in water used in animal food establishments. Yet, the large variation in the type and amount of contamination in an establishment makes it difficult to include all the potential hazards. Factors such as the origin of the biological hazard (human, animal, or environment), the potential for survival, and the difficulty of removal play a role in the degree of contamination of wastewater, and therefore each animal food establishment is unique. Testing for all potential biological hazards is not practical, and the collection of information with a structured quality assessment of the wastewater and recovered water has been described as an important initial step before implementing reconditioning (refer to Glossary) treatments (52).
At the time this report was written, the world is undergoing the COVID-19 pandemic, and many food processing establishments are using more stringent cleaning and sanitation protocols and, in some cases, are disinfecting surfaces to reduce the spread of SARS-CoV-2. Thus, due to COVID-19 processors may be reducing microbial loads further than what is achieved by regular sanitizing procedures.
Contaminants at Different Processing Steps
The transformation of a live animal into human food varies from species to species, but it can be assumed that all the processing steps during the dressing of animal carcasses, where water contacts the carcasses, will have the potential to contaminate the water with, primarily, biological and chemical hazards. Once carcasses are eviscerated and washed and the temperatures lowered, there will be less water contacting the carcasses. Yet, some water is used during cutting, deboning, or portioning and may contain species-specific microbiological hazards.
RESPONSES TO CHARGE QUESTION 4
4. How do residual contaminants in water used for animal production, slaughter, and processing affect product quality and safety? What are the quality implications and public health risks associated with contaminants at levels anticipated for reconditioned water? How might FSIS and industry best assess those implications and risks? How do residual contaminants in water affect the functions of various materials added to water used in all stages of food production and processing, such as feeds, medicines, and antimicrobials? For example, consider the effects of trace pharmaceuticals on animal husbandry and the effects of iron and “hard water” on phosphate-based interventions.
How Residual Contaminants Affect Product Quality and Safety
Not all steps in FSIS-regulated operations require the use of potable water. Wastewater from some processes, with or without additional treatment, may meet the requirements of various, specific reuse and can be safely recycled. For example, Miller et al. (54) found that the use of reconditioned and chlorinated water on swine carcasses during scalding, dehairing, and polishing had no effect on the load of foodborne pathogens (including staphylococci, enteric streptococci, Listeria monocytogenes, coliforms, and Aeromonas) on carcasses (54).
Water used in FSIS-regulated operations can be broadly categorized as having direct contact, indirect contact, or no contact (refer to Glossary) with product. The following gives definitions and examples of each.
Water with direct product contact. Processes in which water used on the product or surfaces comes into direct contact with the product being processed include
• final rinsing of edible product that is not further processed;
• preparation of surfaces including hooks, tables, conveyors, etc., that would have direct contact with meat products or meat packaging materials;
• final rinsing of clean-in-place (CIP; refer to Glossary) systems or manual cleaning systems; and
• direct addition of water as an ingredient in a manufactured meat product.
Water with indirect product contact. Processes in which water inside the meat processing environment is not in direct contact with the product or product contact surfaces include
• environmental sanitation of nonmeat product contact surfaces inside the processing environment, with consideration for the risk of contamination of unprotected meat product contact surfaces by aerosols or transfer of water from the nonproduct contact surfaces; and
• water used as a diluent for cleaning and sanitation chemicals in CIP systems or manual sanitation, excluding the final CIP water rinse.
Water with no product contact. Processes in which water has the lowest risk outside of the meat processing environment include
• boilers and cooling towers, with consideration for the risk of aerosols and transfer of water into the meat processing environments; and
• washing of transport vehicles, with consideration for the risk of cross-contamination from containers to product packaging and then to product.
Spreading nonpotable water on food (i.e., direct contact) may make the food unsafe because this water may contain pathogens and chemicals. Current regulations and guidance to industry found in 9 CFR 416.2(g) and the USDA FSIS (71, 72) guidance for water, ice, and solution reuse in poultry mandate that water must remain free of pathogenic organisms and fecal coliforms and that other physical, chemical, and microbiological contaminants have been reduced to prevent adulteration of product.
Creating various grades of water quality is not practical. The distinction of two water types, one that has direct or indirect contact with food and one that has no contact with food, can simplify the implementation of water reconditioning (refer to Glossary) programs while assuring safety. Currently, both the water standard and regulation of that standard is the responsibility of local authorities and is highly variable across the nation.
Quality and Public Health Implications in Reconditioned Water
The quality of alternatively sourced (see Glossary) water with no direct contact with product that is used inside the processing plant as well as alternatively sourced water with no product contact that is used outside of the processing plant could be of a quality less than potable. Based on animal type, life stage, method of raising, and amount of processing, reconditioned water may vary greatly from plant to plant.
Temperature and turbidity (refer to Glossary) are the physical characteristics that impact safe water usage. Water temperature affects microorganism viability and the solubility of oxygen and increases or decreases the toxicity of ammonia and other substances. Turbidity is a measure of the fine sediment suspended in the water and has no inherent health effects, unless it indicates inadequate filtration that may not have removed protozoa such as Cryptosporidium or Giardia lamblia and/or infectious viruses or bacteria. Turbidity can also interfere with disinfection and may include substances that allow microbial growth.
The chemical characteristics that impact safe water usage include pH, nutrients, ammonia, and dissolved oxygen and metals. Chemical water properties are often interrelated. The pH describes the balance between hydrogen and hydroxide ions that can affect many other chemical constituents such as the dominant form of ammonia and the solubility of metals. Water acidity or alkalinity can cause corrosion (both low and high pH) or precipitation and fouling (high pH). Reused water may have extreme pH values from caustic washes or regeneration of ion exchange resins. Nutrient levels are usually measured as nitrate-nitrite nitrogen and total phosphorus but can be expressed as total inorganic nitrogen, organic nitrogen, or soluble reactive phosphorus. Ammonia is naturally occurring in water but can increase when nitrogen-containing organic waste and dissolved oxygen levels increase. Dissolved metals can include arsenic, lead, mercury, iron, cadmium, copper, sodium, chloride, potassium, manganese, or magnesium. Ingestion and bioaccumulation in tissues can be a health risk for those who consume some metals. Mercury is usually in inorganic form but can convert to toxic methylmercury in conditions of low pH, low dissolved oxygen, and high dissolved organic matter.
Processing water may include residual sanitizing compounds and their by-products. Results from the NRP, described in answers to Charge Question 3, highlight that agriculture and veterinary residues may not be a public health concern in live animals that will be processed when the application of agrochemicals and the use of veterinary drugs follow appropriate guidelines. Please refer to the NRP under responses for Charge Question 3.
The microbiological materials that impact safe water use include pathogenic protozoa, bacteria, and viruses. Organisms of concern include but are not limited to Campylobacter jejuni, pathogenic E. coli, Salmonella (including antimicrobial resistant strains of these pathogenic bacteria), Cryptosporidium, spores of bacterial pathogens, Toxoplasma gondii, norovirus, and helminths. Indicator organisms are often used as a marker or estimate of contamination levels due to cost or inability to monitor the actual pathogen. The biological indicators that highlight the potential for public health risk include the presence of fecal coliforms, E. coli, and enterococci. In the case of parasites such as Cryptosporidium and G. lamblia and viruses such as enteric viruses, direct testing for the pathogen is used, although some recent research suggests that bacteriophages can be used as indicators of fecal pollution and enteric virus removal in recreational water (49).
Australia has developed a national guidance document for water recycling that covers both potable and nonpotable end uses. The guidance document requires the development of a risk assessment process for the “hazards getting through the treatment system in sufficient amounts to pose a risk to human health” (6). In this document, 6 of 52 airborne and waterborne pathogens from water reuse were identified as pathogens of concerns to address when recycling water. Additionally, the guidance document provides recommendations on how to ensure that the risk assessment process, based on examining reference contaminants to represent functional groups of pathogens or chemical contaminants, is compatible with the Australian Recycled Water Guidelines provided by Warnecke et al. (96).
Facilities currently engaging in water reconditioning and reuse are reusing cleaner water for areas where there are more contaminants and use only potable water for direct food contact. Nonpotable water is not allowed as an ingredient and cannot have direct contact with meat in the United States. Most European nations do not allow the use of recycled water in direct contact with meat (61). Guidelines from the World Health Organization (WHO) (98) also highlight that water from alternative sources that has direct or indirect contact with product must meet drinking water guidelines. These types of regulations and guidelines have direct implications for the international meat trade.
The risk of introducing hazards from the reuse of water in operations can be mitigated by using appropriate control measures, including engineering controls (e.g., filtering water on site), administrative controls (e.g., changing job tasks so one individual is not continually exposed or showering out), and personal protective equipment (e.g., gloves, masks, protective eyewear, and coveralls). A risk assessment should be completed when there is a change in systems, animal inputs, or water source or there is the emergence of a previously unidentified hazard. No water reuse system should be allowed to be put in place if it results in an increased risk to human health. Therefore, although there are potential increased hazards with water reuse, no increased risk to public health would occur with proper controls. Each plant will face its own needs and challenges. Using technology coupled with well-trained individuals to implement and monitor systems may protect public health while reducing environmental impacts from water use in meat slaughter and processing.
Assessing Quality Implications and Risks
A report by the Food and Agricultural Organization of the United Nations (FAO) and the WHO (36) addressed the safety and quality of water used in food production and processing. Although this report does not focus on water reuse, its principles are relevant to the question addressed here. The report highlights that water quality should be established on a “fit-for-purpose” basis, considering the application and context, rather than by using the same water quality standards across all applications. In this report, the authors propose the use of decision support system tools that incorporate risk assessments and the use of monitoring to inform stakeholders when making decisions on water quality and reuse at steps in the supply chain (36). A challenge in the use of risk assessments is that monitoring of water quality is often based on microbial indicators, which are not correlated with the presence or quantity of pathogens in water or food. This means that continuous monitoring might have to also include relevant pathogens, depending on the target application of the reused water.
The report also highlights the similarities in risk management approaches in safe potable water and safe food, such as that both are risk and evidence based and need proper verification and monitoring. The report also points out the additional complexities in food production due to the wide range of products, primary production and processing systems, microbial hazards along the food supply chain, and the end use of food products. As a result, the report recommends a risk-based approach to water use and reuse instead of defaulting to specifying the use of potable water or other water quality types (36).
As described earlier, different applications of reused water require different water quality standards. For food contact applications, there are specific U.S. regulations and WHO guidelines on the need to have equivalence to potable water to prevent adulteration of food products with biological hazards (72, 98). The equivalence to potable water should be based on quality indicators, and therefore risk assessment methodologies should incorporate these quality indicators when evaluating the safety of reused water.
Assessing public health risks of an intervention requires quantifying the risk in absolute (i.e., total public health impact) or comparative (i.e., increase or decrease in public health risks from the status quo) terms. For example, assessing the risks from a regulated animal product new to the market would require estimating the absolute public health impact of that product, whereas knowing whether a new regulatory intervention effectively reduces foodborne illnesses would require a comparison of illnesses against current interventions.
Although potable water is safe, food products generated with potable water can still have certain public health risks due to pathogen contamination throughout the production chain. Thus, reused water for use in animal processing should be evaluated to ensure that its use does not result in a net increase (i.e., relative to current water usage practices) in the number of human illnesses, hospitalizations, and deaths attributable to animal products under USDA FSIS regulations. Answering the question of reused water would be amenable to a comparative risk assessment framework.
Regulatory risk assessments applied to food safety risk assessment were published and should follow Codex guidelines, chiefly Principles and Guidelines for the Conduct of Microbiological Risk Assessment (CXG 30-1999) (34) and Working Principles for Risk Analysis for Food Safety for Application by Governments (CXG 62-2007) (35). These guidelines describe the main components of a risk assessment as hazard identification (identify food safety hazards from the intervention), exposure assessment (estimating the extent of anticipated human exposure to the hazard as a result of the intervention), hazard characterization (estimating the severity and duration of negative health outcomes resulting from exposure to the hazard), and risk characterization (obtain a population-level estimate of the public health risks resulting from the intervention). In the United States, the USDA FSIS and the EPA (85) have published the Microbial Risk Assessment Guideline for pathogenic organisms in food and water to achieve a more consistent approach to microbial risk assessment across federal agencies. Such efforts have resulted in an emphasis by U.S. agencies regulating food on performing these fit-for-purpose risk assessments rather than following formulaic or overly strict risk assessment frameworks (29). The USDA FSIS (82) also published a repository of current and past quantitative risk assessments performed since the late 1990s in a variety of inspected products, mostly concerning microbial contaminants. Likewise, the FDA (93) makes available to the public a variety of risk assessments and risk assessment resources for microbial and chemical hazards.
Based on the principle of fit-for-purpose risk assessment, the FSIS and the industry should assess the public health risks using a risk assessment approach for water reuse in food contact applications that do not already require potable water quality. The risk assessment models should be adaptable to the specific food and processing situations. The diversity in the different water use scenarios and food products makes it difficult to recommend any specific risk assessment framework (e.g., qualitative versus quantitative microbial risk assessment), but it should be useful to create a series of use cases to provide examples and guidance of possible risk assessments to apply in FSIS-inspected products.
As proposed by the FAO and WHO (36), following a risk assessment a decision tree could be used to assist industry in deciding the fit-for-purpose of water reuse under four different applications (i.e., as food ingredient, intentional food contact, unintentional food contact, and not for food contact) and conditioning scenarios. An example of a relevant decision tree is provided in Figure 1. Thus, the risk assessment and decision tree framework should be flexible enough to accommodate such diversity.
Effect of Residual Contaminants on Materials Added during Food Processing
Residual contaminants (refer to Glossary), as indicated by high turbidity in nonpotable recycled water, may inhibit the ability of antimicrobials added to the water to reduce pathogens in water or food. Turbidity can interfere with disinfection and may include substances that allow microbial growth (25). Thus, highly turbid or contaminated water should not be used in the facility before further processing (see responses to Charge Question 2).
RESPONSES TO CHARGE QUESTION 5
5. What are the best ways to assure and/or monitor the quality and safety of alternatively sourced water used in FSIS-regulated operations?
The safe use of reconditioned water requires monitoring to validate the initial processes and ongoing verification so that water quality is consistent. The water source characterization and its intended reuse will direct the allowable levels of substances. Initial monitoring of alternatively sourced water should be extensive and may involve independent accredited laboratories, and ongoing performance monitoring should be in real time and can focus on measuring indicators rather than on a complete analysis.
Source water (refer to Glossary) assessments consider a range of possible contaminants and can be derived from lists such as the Guidelines for Drinking-Water Quality by the WHO (98) and the WHO guidelines on the management of chemical contaminants (66). After the source vulnerability assessment, it is not necessary to continually assess all potential contaminants, and analyses can focus on the relevant contaminants. The specific physical, chemical, and microbiological parameters to be monitored, the frequency of monitoring, and on-line versus discrete analyses should be chosen based on the distinct contamination vulnerability of the source water.
Monitoring Quality and Safety of Alternatively Sourced Water
Effective methods to monitor and ensure water quality and safety are in use by municipal wastewater treatment plants. Removal of nutrients and pathogens has been the focus of these facilities for over 100 years. The same methods can be used for alternatively sourced water. Typical wastewater treatment is monitored (using indicators) for the elimination of all pathogenic microorganisms, except for spores.
The monitoring of parameters for recycled water includes investigation, process performance, and verification. Initially, an investigative, comprehensive assessment of contaminants in the source water should be done because they may impact recycling. Annual water analysis should document the overall quality of the incoming water and meet the regulatory requirements. Standard water analysis methods are available, well developed, and reliable (4). The potential contamination in waters is evaluated by testing different parameters, such as pH, total dissolved solids, total organic carbon (TOC), ammonia nitrite, nitrate, hydrogen sulfide, dissolved oxygen, chloride, chlorine, sodium, sulfate, turbidity, urea, etc. TOC is an excellent indicator of the treatment process performance, and there are manual and in-line monitoring systems for rapid and inexpensive TOC evaluation. Total dissolved solids can be detected by electrical conductivity, a measurement that provides information on dissolved inorganic ions in water.
The presence of potential human pathogens is evaluated by testing for bacterial indicators, such as total bacteria (by aerobic plate counts), coliforms, E. coli, etc. Depending on the incoming source, an initial analysis for lipid, protein, lactose or sugar, and minerals may be needed to be sure the water quality will not adversely affect products or processes. After the water is used in processing, other tests should be considered, such as testing for residues of sanitizers or the accumulation of metal cations. The type of parameters to monitor and the frequency of monitoring will also depend on whether the water is used directly on foods or food contact surfaces or on nonfood contact surfaces.
The physical parameters of water include turbidity, which is an important indicator of microbial quality (e.g., bacteria, parasites, and viruses). In-line turbidity meters with alarm systems are available at relatively low cost. Depending on the intended water use, real-time monitoring of turbidity is recommended, and standard acceptable levels have been set (89).
The chemical parameters of water coming into the facility from outside should be known. There should be an initial testing when a new source of water is used. Once the composition of the source water is known and the treatment process is in place, the chemical composition does not need frequent monitoring. There are numerous chemical indicators used to characterize the quality of the water, such as specific metals (e.g., Fe, Mn, and Pb), radionuclides (e.g., radium 226 and 228 and uranium), anions (e.g., SO4 and NO3−), silica, nutrients (e.g., NH3− and phosphorus oxyanions), and some specific synthetic organics. Color is generally an indicator of organics in the water and is readily measured by visual or spectrophotometric methods. Odor is important, and poor quality can be indicated by objectionable aromas of sulfide or algal products.
Disinfectant residuals such as chlorine, chlorine dioxide, or chloramine could be detrimental to some products. Ozone dissipates rapidly, and UV light provides immediate disinfection with no residuals. One or more disinfectants are required as part of the treatment process to ensure microbial safety. Additionally, routine residual measurements are important to establish presence and/or absence of residuals. Inexpensive disinfectant residual test kits are available. However, in-line monitors for chlorine and ozone are preferred for continual monitoring of microbial safety.
The microbial parameters of water should be monitored frequently because contamination risks are acute. Reclaimed water (refer to Glossary) used in direct or indirect contact with product should receive secondary treatment with disinfection. Also, for noncontact water reuse, identification of potential fecal contamination is an issue for worker safety.
Safety measures can include monitoring of filtration and disinfection and for the presence of residual disinfectants. In general and for different types of waters (e.g., drinking, recreational, and animal processing), microbiological water testing is used to detect indicator organisms, rather than specific pathogens, as a sign of fecal contamination. However, it is important to emphasize that many microbial indicators (e.g., coliforms, E. coli, and enterococci) have been used to assess fecal pollution, but there is no direct correlation between the levels of any microbial indicator in water and the presence of an enteric pathogen (9, 37).
Heterotrophic plate counts (refer to Glossary) are used to estimate the level of live heterotrophic microorganisms in water and provide some information about water quality. Yet, the test itself does not specify the organisms that are detected, and a wide range of quantitative and qualitative results can be obtained (12). Total coliforms are another bacterial group that can indicate potential contamination, but coliforms can originate from many sources and are not good sanitary waste indicators. Another group are the FIB (see response to answers for Charge Question 3), which have been used by public health agencies for several decades to identify potential for illness resulting from recreational activities in surface waters contaminated by fecal pollution (87).
The EPA recommends the use of FIB, specifically enterococci and E. coli, as indicators of fecal contamination for fresh water and enterococci as indicators of fecal contamination for marine water (85, 87). FIB are considered pathogen indicators (refer to Glossary), but the EPA recognizes that these microbial groups are not used as direct indicators of pathogens by the scientific community (87). In addition, the EPA has not yet published any criteria for pathogens per se (87).
Historically, E. coli was considered an appropriate indicator organism for determining the potential presence of bacterial fecal pathogens in reused wastewater. However, contemporary research highlights that E. coli may not be an effective indicator of water quality because it appears and grows in natural environments in addition to the intestines of warm-blooded animals (97). The large diversity among E. coli strains and the actual sources of the majority of the E. coli strains isolated from the environment may not be identified by a library-dependent method (refer to Glossary) (39, 40). The use of other indicators, such as bacteriophages (49), to assess fecal pollution and enteric virus removal in recreational water also brings uncertainties and has limitations for the modeling of microbial populations in recreational water. Thus, we do not know the most appropriate indicators for each food animal species that is processed. However, as our knowledge in this area increases, we expect to find other microorganisms or DNA markers that could be used to assess the level of pollution in waters.
Microbiome sequencing has been suggested as the next method to help evaluate the efficacy of cleaning and sanitation practices and antimicrobial interventions and to provide information on the quality of recycled water in animal processing establishments (16, 33). Microbiome mapping using DNA data from next generation sequencing may help processors understand the key microbes on food products and in the processing water.
There are real-time in-line monitoring systems available to evaluate the physicochemical properties and quality of recycled water. In-line monitors are available for pH, conductivity, turbidity, particle counts, TOC, and many individual chemicals. In-line electrical conductivity monitors are inexpensive and provide information on salinity, and in-line pH systems are simple and cost-effective. Other in-line monitoring systems are expensive and require regular calibration, maintenance, and trained personnel. Currently, there are no real-time in-line monitoring systems to detect and count microorganisms. However, signals from in-line chlorine and turbidity tests could in the future be used to assess the level of microbial contamination in water.
Verification monitoring is needed when a system does not meet specifications and corrective action is implemented. This monitoring assures performance and requires an increased monitoring frequency until specifications for the specific parameter are consistently met. This is critical if the recycled water has any product contact potential.
RESPONSES TO CHARGE QUESTION 6
6. Are there special considerations for foods that are produced entirely within water (e.g., fish), and if so, what are they?
The answers to this specific question focus on the growing, transporting, and processing of channel catfish (a siluriform fish).
Channel catfish (Order Siluriformes) are raised primarily in ponds in the southern states of Mississippi, Alabama, Arkansas, and Texas, accounting for 95% of annual U.S. sales of channel catfish. Channel catfish production was valued at $380 million in 2018 in the United States (58), and over 90% of the commercial channel catfish is produced in embankment or levee types of ponds, which keep the water free of pollutants and other species of fish. These water impoundments are constructed on flat land where the dirt has been moved into a levee around the pond bottom and usually range from 8 to 25 acres (3.2 to 10.1 ha) with a depth of 4 to 6 feet (1.2 to 1.8 m) (8). Another system of channel catfish production is the split-cell pond, where a traditional pond is split in half with an earthen dam. This system is more efficient and may increase the production per acre compared with embankment or levee types of ponds, but it requires much more intensive aeration management due to the increased stocking rate (26).
The ponds in which channel catfish are produced must yield fish that are healthy and wholesome for human consumption. Ponds are typically filled with nontreated water from a ground well. This water is used throughout the fish growing period and is replenished as needed. Water conservation measures have been implemented to maximize capture of rainwater and at the same time prevent ponds from overflowing and losing water during heavy rains (68, 69). Some ponds are drained and refilled annually; however, most ponds are often used for up to 10 years without draining.
Maintaining good water condition is essential to control fish diseases and to provide adequate production of channel catfish. As with all food animal production systems open to the environment, fishponds could potentially become exposed to foodborne pathogens from other animals (wild and domestic) that have access to the area, but it does not appear to impact the success in raising wholesome channel catfish (76). Because the water is used all year and replenished as needed, there is no economic or other type of incentive for water conservation or recycling, although some conservation practices have been described (69).
Producers monitor pond water for production-related parameters (e.g., dissolved oxygen, temperature, pH, alkalinity, hardness, and total ammonia nitrogen), and the USDA FSIS is responsible for monitoring ponds for environmental chemicals and pesticides that can impact food safety (76).
Catfish are harvested from ponds and transported to the processing establishments in live-haul trucks that contain aerated water-filled tanks. The water in transport tanks may be sourced from wells or the production pond. Wynne and Wurts (100) recommended that the transport truck be scrubbed using a detergent followed by a disinfection spray and then rinsed. It is unclear whether this recommendation is regularly followed in the industry. When trucks are used for multiple runs from the same pond, disinfecting after every load may not be practical. Cleaning and disinfecting trucks is a biosecurity measure to control the spread of diseases between fish rather than a sanitation measure associated with food processing. Reduction of water use in catfish transportation appears to be unlikely due to the concern with preventing transport stress and disease transmission between loads.
Channel catfish processing comes under the jurisdiction of the USDA FSIS; therefore, sanitation performances standards and SOPs apply to water use and water supply as mandated by 9 CFR 416.2(g) (71, 72). These requirements are adequate for channel catfish processing. As with other food animal processing, there may exist water reclamation and reuse opportunities as long as the wholesomeness of the product is not compromised.
Guimarães et al. (38) evaluated the possible reuse of water in seafood processing in Brazil. These authors evaluated industrial water management and quantified and qualified effluents from general processing activities and concluded that direct reuse of processing water could not be recommended due to the high number of bacterial contaminants. However, the authors also concluded that indirect recycling of water from freezing tunnel and cooling chamber defrosting could be used to supply cooling tower demands after a simple treatment and disinfection process. It was estimated that this practice might reduce total average water consumption of the processing unit by 11%. It was also noted that if effluents from cooling tower purges were also reused, water reductions of approximately 22% could be attained.
Similar to the high number of bacterial contaminants described by Guimarães et al. (38), other food industries (e.g., beef processing and poultry processing) that have implemented processes to capture, treat, and reuse water have also reported high levels of bacterial contaminants in the water captured for recycling (20). However, various treatments have been proven to be effective at bringing the water back to potable standards in order to be reused (20). Although technologies for the recycling of water in food manufacturing exist, which could also be useful in recycling water in the fish industry, these technologies would have to be economically beneficial for the processing facility to implement.
RESPONSES TO CHARGE QUESTION 7
7. Flooding can contaminate animals and water sources with human sewage and farm waste. What precautions should establishments take when floodwater or runoff affects a food or water source or a processing area?
Flooding events are considered “significant incidents” by the USDA FSIS (77), meaning they represent grave or potentially grave threats to people or products. These events could trigger a significant incident response by the Agency. Depending on the scope of the emergency, such an event could trigger response actions under the National Response Framework, National Response Plan, and state emergency management activities (79). The USDA FSIS (79) significant incident preparedness and response program is a resource for education, collaboration, and assistance with preparing emergency response plans.
Food production companies should have documentation for managing natural disasters, such as flooding in a facility, that clearly define preparedness and response actions. This documentation may be a corporate-level document that outlines general action items for establishments and/or establishment-level contingency plans or emergency response plans. These documents will give direction on how to manage such situations and typically include checklists that provide guidance. General guidance on flooding preparedness is available for processing facilities, including small and very small facilities, at the USDA FSIS Web site (74). Companies also need to consider following state guidelines (e.g., the New Jersey Department of Health Emergency Action Planning Guidance for Food Production Facilities) (7).
A documented flood emergency response plan can give the facility staff a step-by-step course of action to follow in times of need and help minimize losses for a business. Time invested in training and educating staff members for natural disasters will help to keep team members and animals safe.
Industry-driven audits of food safety systems require facilities to have procedures designed to effectively manage and report incidents and potential emergency situations that impact food safety, quality, or legality, including appropriate contingency plans. Incidents such as fire, flood, other natural disasters, malicious contamination or sabotage, and digital cyber attacks may result in disruption to key services such as water, energy, transport, refrigeration, staff availability, and communication. Facility operators should consider whether products from their site may have been affected by an incident before releasing these products to market.
Floods or other natural disasters affecting an animal production facility need an immediate and humane response to find, assess, and secure the affected animals consistent with the provisions of the Animal Welfare Act (70) and with worker safety. When animals are present in a facility during a flooding event, facility managers should follow established and applicable animal welfare policies to remove animals to a safe and secure area (73, 75). These actions may include moving animals to safe locations, rinsing them down if heavily soiled, managing and containing animal waste and contaminated water in accordance with applicable regulations, rinsing down and cleaning all surfaces, sanitizing animal contact surfaces with approved products, and forced air drying to prevent mold growth.
Following a flooding event in which flood water has entered an animal or processing facility, managers should follow the SOPs in their emergency response plan to mitigate facility contamination and damage in order to return the facility to a safe operational state. Large debris or gross contamination can be removed from surfaces with clean water. Fans or other mechanical drying equipment can be used to dry wetted surfaces more quickly to reduce potential molding. Surfaces that have been contaminated by floodwater should be cleaned with an approved cleaning product appropriate to the setting and operational process. If these surfaces come in contact with animals or animal products, they should be sanitized with an EPA-registered sanitizer.
A facility's emergency response plan should also take into consideration potential damage to and contamination of the facility's water supply and distribution system. Whether for worker or animal health or maintaining facility operations or product quality, a safe water supply is a critical resource that needs to be incorporated into emergency preparedness and mitigation plans for animal growing and processing (Appendix 1). Water-related emergency preparedness at a facility includes understanding the water supply and how water is used in the facility. Flood water can contain pathogens, chemicals, and toxins that can contaminate a facility's water supply at its source, during treatment, or during distribution. If mitigation or preventive measures are not taken, this contaminated water may be consumed by workers or used for facility production processes such as animal care and facility cleaning. Clean, safe water is essential for human and animal consumption, proper hygiene, surface cleaning, and hand washing. It is important for facilities to ensure their water supply is safe for intended purposes (Appendix 1).
When a facility is served by a municipal water system that experiences flooding, managers should check with the local water authority to determine whether a drinking water advisory has been issued and whether any precautions should be considered (23). Many water utilities also offer text-based alert systems for rapidly notifying customers of any drinking water advisories. State health departments may also have guidance on emergency planning for water advisories and interruption of water service (7). If the facility uses a groundwater well, managers may consider consulting a well or pump contractor to have the well inspected to determine whether it or associated equipment has been damaged during flooding or is not working properly. If managers suspect that a facility's groundwater source might have been contaminated by floodwater, they can contact their local or state health department or agriculture extension office for advice on disinfecting the well (22). Before resuming use for drinking or production, the well should be tested for appropriate fecal and chemical water quality parameters (21).
A facility's water emergency and preparedness plan will include detailed information and procedures to enable facility staff and remediation personnel to respond to and recover from interruption of the facility's water supply. This plan will typically identify alternative water sources and mitigation procedures (e.g., posting signage that water is not safe for consumption or using alternative procedures when tap water is not appropriate for process use). In addition to considering alternative water supplies, facility managers can benefit from planning for actions to remediate the facility's water supply, distribution, and building plumbing systems (also known as premise plumbing). Mitigation planning includes identifying water system repair and rehabilitation companies that can quickly respond following a flood event, having documents ready to assist in the system repair and rehabilitation process, and ensuring that the facility water system is effectively flushed to remove contaminated water and contaminant residues (13).
The guidance document from the Centers for Disease Control and Prevention (CDC) and the American Water Works Association (AWWA) (24), Emergency Water Supply Planning Guide for Hospitals and Healthcare Facilities, on developing emergency water supply plans for health care facilities may be helpful to animal growth and production facilities. These checklists and decision trees could be adapted to food production facilities during the preparation for and response to a water supply interruption. Similar guidance could be developed to provide information and tools to food processing facilities interested in developing water preparedness plans.
Steps and considerations in preparing a food processing facility water preparedness plan include (Fig. 2)
1. identify the facility's water supply and operations team;
2. understand the facility water usage by conducting a water use audit, including assessment of facility water taps and processes that could present risks that may need to be mitigated if the water supply is suspected to have been compromised by flooding;
3. analyze the facility's emergency water supply alternatives:
review and incorporate applicable rules and guidance from local, state, and federal authorities,
identify alternative sources of water that can be obtained and used for facility operations, including drinking or use in facility processes, and
identify critical partners that can assist with obtaining alternate water sources or rehabilitate the facility's established water source and building plumbing system;
4. develop and test the emergency water supply plan:
develop messaging examples to provide facility workers with guidance on consuming or using water in the facility,
develop alternative procedures in the event the facility water supply is compromised and not suitable for use or consumption, and
educate and train staff on water-related preparedness for the facility.
RESPONSES TO CHARGE QUESTION 8
8. What technologies are appropriate for the replacement of liquid water in food production and food processing areas (i.e., foam, mist, or dry chemicals)? What advanced emerging technologies may reduce the need for or volume of water in processing?
Alternative water-sparing processes may be considered, such as air chilling a product in place of chilling in a water bath and using recycled water and wastewater for specific purposes (refer to Charge Question 2). Recycled water can be used for product contact equipment rinsing, provided that the provisions of 9 CFR 416.2(g)(3) and (4), where applicable, are properly addressed (71, 72). Strategies that prevent contamination from being brought into a clean processing area may enhance the overall effectiveness of a cleaning program, such as using boot disinfection stations and limiting wheeled equipment to specific zones. Staff training with regular updates can maintain and reinforce cleaning and water-sparing behaviors.
Cleaning, sanitizing, and disinfecting are critical components of a facility's program during routine operations and for recovery activities following a flood or other contamination event. Cleaning is the process of removing contaminants from a surface that could be harmful to human or animal health, damage equipment, lead to process inefficiency, or impact product integrity or safety. Cleaning processes and chemical products are not designed to kill bacteria, viruses or fungi but rather to remove them from surfaces along with dirt, oils, and other inorganic and organic materials. Sanitizing and disinfecting (refer to Glossary) are related concepts, as both are focused on killing or inactivating microorganisms, including pathogens. Disinfectant products and processes are those that result in a more rigorous removal or inactivation of microorganisms of public health concern than sanitizing products (sanitizers) and sanitizing processes (Appendix 2). For example, there are no sanitizer-only products with EPA-approved virus claims, but there are sanitizer-only products with EPA-approved bacteria claims because vegetative bacterial cells (although not bacterial spores) are generally easier to inactivate than are virus particles (64).
When choosing a sanitizer or disinfectant, it is important to consider what level of sanitizing or disinfection is indicated for each facility process and what the product is registered to do (i.e., the label claims). Some products can have both claims, as a sanitizer and as a disinfectant, depending on variables such as concentration and contact times (Appendix 2).
The general steps in cleaning and sanitizing food contact surfaces are site specific and variable. Wet cleaning of an establishment includes a cleaning step, which may include the use of detergents, to remove as much organic matter as possible and may be accompanied by physical actions, such as scrubbing, pressure, etc. Sanitizers are applied after cleaning. Dry cleaning protocols (refer to Glossary) also include mechanical removal of soil or residue, aided with vacuum, compressed air, or compressed steam, and wiping with alcohol-based swabs or moistened pads, followed by towel drying (Table 7). Dry sanitizing and disinfection treatments can reduce microbial contamination, using products based on a variety of mechanisms of antimicrobial action and approved by the EPA for use on food contact surfaces (Table 8). A critical final step is often a disinfectant treatment that may intentionally leave an antimicrobial residue.
Most cleaning, sanitizing, and disinfecting approaches standard in the protein food processing industry are water intensive. Several water-sparing technologies may have uses that could reduce dependence on water for these basic steps (Table 8). Many of these technologies were developed first for use in dry and ready-to-eat food processing environments, where waterless cleaning and disinfection has been widely adopted, and may also have applications in meat and poultry processing. Novel sanitizers and disinfectant strategies may offer similar bacterial load reduction and disinfection while using less water. Whole room or closed chamber treatments with fogs or UV light may help reduce bacterial loads on exposed surfaces without requiring any water at all. Surface treatment preparations that do not require a final rinse may reduce water use.
Sanitizers and disinfectants for use on food contact surfaces are registered as antimicrobial pesticide products under the FIFRA by the EPA (refer to Charge Question 3), which reviews data from standard microbial reduction effectiveness assays to validate public health claims for particular uses, such as treatment of hard surfaces (86, 90). Whole room treatments using disinfectant products delivered as a fog are registered for that delivery system. But novel cleaning and sanitizing products may help reduce use of water. For instance, cleaning solutions based on quaternary ammonium compounds can be used with premoistened wipes as an alternative to well-established chlorine-based wipes. Sanitizing solutions based on ∼60% isopropyl alcohol and quaternary ammonium compounds may introduce little water.
UV light treatments and ozone may have applications in enclosed spaces, as an adjunct to other treatments, with adequate precautions for worker safety. These alternatives (UV light and ozone) are regulated by the EPA as devices and are not registered nor granted health claims by the Agency (91). The EPA is also developing regulatory strategies for the new and rapidly expanding category of surface treatments or coatings with sustained antimicrobial properties. Copper alloys, which are registered by the EPA (88) as surface antibacterials with limited sanitization claims and not for food contact surfaces, have been described for use in hospitals and other clinical facilities and have limited though long-lasting effects and validated bacterial effect claims (57). Some coatings are registered but do not have public health pathogen claims. Silver alloys have been incorporated into poured floors and other surfaces to make them more mold and mildew resistant. Surface treatments for food contact surfaces may offer a longer lasting residual antimicrobial effect, although published practical experience with them is limited. Similar experience is beginning to be reported from health care settings (18). Once a standard test protocol is developed, including assessment of how long effectiveness lasts, more coatings with residual antimicrobial effects lasting for weeks or months are likely to be registered with specific health claims. In the future, with more published experience and EPA registration, such technologies may offer efficient sanitizing and disinfection in combination with more routine cleaning methods, while using less water.
When considering a novel technology, it is important to evaluate several critical points.
1. Is the new technology involving sanitizing or disinfecting registered with the EPA as either a sanitizer or as a disinfectant for use on food contact surfaces? The appropriate criteria for one or the other (Appendix 2) need to be met if the technology is to be used for those purposes on a food contact surface. If the new technology is a device or surface coating, the company will need to evaluate the available antimicrobial effect data because the technology is not registered with the EPA for health claims.
2. What published or other experience is available showing that in a practical use case the technology achieved reductions in both the pathogen load and in the volume of water used in cleaning and disinfection? The nature of that experience needs to be carefully considered, including whether the impact was measurable with standard monitoring tests already in use in the facility's water use plan. A hierarchy of evidence has been described for evaluating products used in the health care sector (48). A similar approach may be useful in evaluating reported experiences in the food processing sector.
3. Does the technology make economic sense, so the value of the water saved at least equals the cost of applying the novel strategy? That may include the cost of water piped in, sewage costs incurred, and the cost of implementing the new technology (67).
4. Is the new process readily accepted by the workforce? What additional training and ongoing reinforcement will be needed?
5. How can existing sanitization performance standards and sanitary standard operating procedures be adapted to include the new process? Are ongoing environmental and product monitoring tests in place to provide ongoing assessment of the impact on microbial targets?
6. If the technology is adopted, what evaluation at future time points will be made to determine the impact on actual water use as measured in the ongoing water management plan?
NACMCF acknowledges the contribution of Dr. Susan R. Hammons (FSIS) for critical review and formatting this report for publication. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA and other participating agencies.