| Summary: | 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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