Salmonella contamination in a dry processing facility frequently requires removal methods that are non-aqueous. Removal of pathogens from food processing systems with a purge of uncontaminated dry food materials has been proposed, however, little is known with the respect to efficacy. In this study, survival of Salmonella on inert contact surfaces and transfer of Salmonella from inert contact surfaces to low-moisture foods was evaluated. Six stainless steel and polymeric food contact material types, in bead form, were contaminated at 11 log CFU/mL and then stored at two temperatures, 25°C and 4°C for six months. Simultaneously, three dry food materials/ingredients were used to remove Salmonella from contaminated beads. Wheat flour, cornmeal, and NaCl (1 g each) were mechanically mixed with 3 beads of each material type. The rate of microbial transfer from contaminated beads to food materials was measured. Further experimentation using multiple transfers were applied on two representative beads types, 316 stainless steel and polypropylene, representing common surface contact materials used in processing equipment. Survival of Salmonella on beads depended on storage temperature, surviving longer at 4°C compared to 25°C (p<0.05), but was not influenced by type of bead material. Transfer of Salmonella from stainless steel beads to flour was significantly greater than from plastic (p<0.05). Transfer rates from stainless steel to wheat flour, cornmeal, and NaCl were measured as -0.5713, -0.2592, and -1.4221 Log CFU Salmonella removed/cm 2 /g clean material used. Transfer rates for polypropylene to whole wheat flour, cornmeal, and NaCl were more than 10-fold lower at -0.0156, -0.0148, and -0.0129 Log CFU Salmonella removed/cm 2 /g clean material used. These results indicate that while material type may not influence Salmonella survival during storage, Salmonella is more easily removed from stainless steel than polyethylene.
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Research Article| October 06 2021
Transfer of Salmonella from inert food contact surfaces to wheat flour, cornmeal and NaCl.
Susanne E. Keller;
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Siman Liu, Susanne E. Keller, Nathan M. Anderson; Transfer of Salmonella from inert food contact surfaces to wheat flour, cornmeal and NaCl.. J Food Prot 2021; doi: https://doi.org/10.4315/JFP-21-225
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