Hand washing is recognized as a crucial step in preventing foodborne disease transmission by mitigating cross-contamination among hands, surfaces, and foods. This research was undertaken to establish the importance of several keys factors (soap, soil, time, and drying method) in reducing microorganisms during hand washing. A nonpathogenic nalidixic acid–resistant Enterobacter aerogenes surrogate for Salmonella was used to assess the efficacy of using soap or no soap for 5 or 20 s on hands with or without ground beef debris and drying with paper towel or air. Each experiment consisted of 20 replicates, each from a different individual with ~6 log CFU/ml E. aerogenes on their hands. A reduction of 1.0 ± 0.4 and 1.7 ± 0.8 log CFU of E. aerogenes was observed for a 5-s wash with no soap and a 20-s wash with soap, respectively. When there was no debris on the hands, there was no significant difference between washing with and without soap for 20 s (P > 0.05). Likewise, there was no significant difference in the reductions achieved when washing without soap, whether or not debris was on the hands (P > 0.05). A significantly greater reduction (P < 0.05) in E. aerogenes (0.5 log CFU greater reduction) was observed with soap when there was ground beef debris on the hands. The greatest difference (1.1 log CFU greater average reduction) in effectiveness occurred when ground beef debris was on the hands and a 20-s wash with water was compared with a 20-s wash with soap. Significantly greater (P < 0.05) reductions were observed with paper towel drying compared with air (0.5 log CFU greater reductions). Used paper towels may contain high bacterial levels (>4.0 log CFU per towel) when hands are highly contaminated. Our results support future quantitative microbial risk assessments needed to effectively manage risks of foodborne illness in which food workers' hands are a primary cause.
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April 01 2015
Quantifying the Effect of Hand Wash Duration, Soap Use, Ground Beef Debris, and Drying Methods on the Removal of Enterobacter aerogenes on Hands
DANE A. JENSEN;
DANE A. JENSEN
1Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, New Jersey, 08901
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MICHELLE D. DANYLUK;
MICHELLE D. DANYLUK
2Department of Food Science and Human Nutrition, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, Florida 33850
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LINDA J. HARRIS;
LINDA J. HARRIS
3Department of Food Science and Technology, University of California, One Shields Avenue, Davis, California 95616, USA
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DONALD W. SCHAFFNER
DONALD W. SCHAFFNER
*
1Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, New Jersey, 08901
* Author for correspondence. Tel: 732-982-7475; Fax: 732-932-6776; E-mail: schaffner@aesop.rutgers.edu.
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J Food Prot (2015) 78 (4): 685–690.
Article history
Received:
May 28 2014
Accepted:
August 29 2014
Citation
DANE A. JENSEN, MICHELLE D. DANYLUK, LINDA J. HARRIS, DONALD W. SCHAFFNER; Quantifying the Effect of Hand Wash Duration, Soap Use, Ground Beef Debris, and Drying Methods on the Removal of Enterobacter aerogenes on Hands. J Food Prot 1 April 2015; 78 (4): 685–690. doi: https://doi.org/10.4315/0362-028X.JFP-14-245
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