15D-2 |
Efficacy of detergents to enumerate Salmonella spp. from the surface of fresh produce |
R. M. Raiden1, S. S. Sumner, M. D. Pierson, J. D. Eifert, and R. C. WILLIAMS1. (1) Food Science and Technology Dept., Virginia Polytechnic Institute and State University, 22 Food Science Building, Blacksburg, VA 24061 Fresh produce is responsible for a growing number of foodborne outbreaks each year. These products are minimally processed and lack a thermal processing step making it difficult to ensure their safety. Since a significant amount of microbial contamination may be found on the surfaces, steps need to be taken to develop an effective rinsing agent to significantly reduce pathogens from produce surfaces. Our objective was to use different detergent rinse agents at room temperature and 40oC to determine their efficacy for removal of Salmonella spp. from the surface of fresh produce. Strawberries and tomatoes were dip inoculated at room temperature with a 7 X 106 CFU/ml cocktail of nalidixic acid resistant Salmonella and allowed to dry. A 0.1 % solution of Tween 80 and sodium lauryl sulfate (SLS) in sterile water were added to Whirlpak bags containing produce and allowed to rotate on an orbital shaker for 2 minutes. Rinse solutions were then plated onto Tryptic Soy agar supplemented with 50ppm nalidixic acid. Plates were incubated at 35oC for 24 hours. Results indicate that the detergents were no more effective in the removal of organisms than sterile water for both produce types. In each trial 1 X 104 CFU/ml were recovered from each sample, respectively. Recovery from strawberries was slightly higher, and tomatoes slightly lower. When strawberries were rinsed with SLS, there was minimal recovery of organisms at room temperature, and no recovery at 40oC. These results indicate that the use of these detergents would not generally enhance the removal of microorganisms; therefore this would not be an effective rinse agent to ensure produce safety. The lack of recovery of organisms from strawberries rinsed with SLS, suggests that either the strawberry is internalizing the organisms preventing recovery, or SLS is inactivation Salmonella, especially when a 40oC solution is used.
Session 15D, Food Microbiology: Fruits and vegetables
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