MICROBIAL ECOLOGY AND SAFETY OF FRESH ON-FARM ORGANICALLY GROWN PRODUCE
Title: Chlorine Stabilizer T-128 enhances efficacy of chlorine against cross contamination by E. coli O157:H7 and Salmonella in fresh-cut lettuce processing
Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 10, 2010
Publication Date: March 14, 2011
Citation: Nou, X., Luo, Y., Hollar, L.A., Yang, Y., Feng, H., Millner, P.D., Shelton, D.R. 2011. Chlorine Stabilizer T-128 enhances efficacy of chlorine against cross contamination by E. coli O157:H7 and Salmonella in fresh-cut lettuce processing. Journal of Food Science. 76(3):M218-M224.
Interpretive Summary: Chlorinated water is commonly used for fresh-cut produce processing to prevent pathogen contamination. Organic materials released from the cut surfaces and soil can result in rapid free chlorine depletion, creating potential for cross contamination by bacterial pathogens. In this study a reported free chlorine stabilizer was evaluated for effect on chlorine stability and washing efficacy, as well as produce quality. Chlorine stabilizer T-128 was determined to enhance the efficacy of chlorinated wash solution against potential cross contamination in the presence of high level of organic material, without compromising product quality and shelf life. These results are of particular importance to the fresh produce industry because it may help to minimize produce contamination.
During fresh produce processing, organic materials released from cut tissues can rapidly react with free chlorine in the wash solution, leading to the potential survival of foodborne bacterial pathogens and cross-contamination when the free chlorine is depleted. A reported chlorine stabilizer, T128, has been developed to address this problem. In this study, we evaluated the ability of T128 for stabilizing free chlorine in wash solutions at the presence of high level of organic loads generated by the addition of lettuce extract or soil. Under conditions used in this study, T128 was found to have marginal to moderate effects on free chlorine concentration in wash solutions containing high organic loads. Application of T 128 significantly reduced the survival of Escherichia coli O157:H7 and Salmonella spp. in wash solution with high organic loads and significantly reduced the potential of cross contaminations when contaminated and uncontaminated produce were washed together, although it did not enhance the efficacy of chlorinated wash solutions for microbial reduction on contaminated iceberg lettuce. Evaluation of several produce quality parameters, including visual appearance, package head space O2 and CO2 composition, and lettuce tissue integrity, during 15 days of storage indicated that iceberg lettuce quality and shelf life were not negatively impacted by washing fresh-cut lettuce in chlorine solutions containing 0.1% T128.