Effect of sanitizer treatments on Salmonella enterica serotype Poona on the surface of cantaloupe and cell transfer to the internal tissue during cutting practices

Date

2005-02-17

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Publisher

Texas A&M University

Abstract

In recent years, due to the increasing number of produce-related outbreaks, greater attention has been given to interventions that remove human pathogens on fresh produce. Survival of Salmonella Poona on the surface and stem scar portions of inoculated cantaloupe, effect of chlorine or lactic acid or ozone on the survival of bacteria, transfer of pathogen from the rind to the fresh-cut tissue during cutting and growth and survival of Salmonella Poona on the fresh-cut tissues during 15 days of refrigerated storage were investigated. Preliminary studies were conducted to confirm that the rifampicin-resistant strain used in the study was indistinguishable from the parent strain of Salmonella Poona. Growth curve, heat tolerance and lactic acid resistance studies were performed, all of which showed no differences in behavior between the organisms. Cantaloupes were immersed in an inoculum containing rifampicicn-resistant strain of Salmonella Poona (107 CFU/ml) for 3 min and then dried for 12 h. The inoculated melons were washed with chlorine (200 ppm) for 3 min or lactic acid (2%) for 2 min or ozone (30 ppm) for 5 min and fresh cut tissues were prepared by peeling the rind and cutting into pieces or cutting the melon and removing the rind. Results obtained indicate that the levels of Salmonella Poona recovered were higher when the sample was obtained from the scar portion than the surface. Surface treatment with tap water or chlorine did not reduce Salmonella Poona. However treatment with lactic acid or ozone reduced the levels by 2.5 and 2.3 log10 CFU/cm2 respectively on the surface. Fresh-cut tissue prepared from melons sanitized with lactic acid resulted in less transfer during cutting and reached below detectable limits after 9 days of refrigerated storage. Cutting melons after peeling the rind was found effective in reducing the transfer of Salmonella Poona into the tissue in comparison with cutting of melons and removing the rind later. Thus these data suggest that treatment with lactic acid and ozone may be effective in reducing Salmonella from the surface of the cantaloupe where as lactic acid was effective in reducing the transfer from the surface to the flesh.

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