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United States Department of Agriculture

Agricultural Research Service

Title: SURFACE PASTEURIZATION OF WHOLE CANTALOUPES INOCULATED WITH SALMONELLA POONA OR ESCHERICHIA COLI

Authors
item Annous, Bassam
item Burke, Angela
item Sites, Joseph

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 29, 2004
Publication Date: September 1, 2004
Citation: Annous, B.A., Burke, A.M., Sites, J.E. 2004. Surface pasteurization of whole cantaloupes inoculated with salmonella poona or escherichia coli. Journal of Food Protection. 67(9):1876-1885.

Interpretive Summary: Cantaloupes have been implicated in numerous foodborne outbreaks due to contamination with pathogenic Salmonella and Escherichia coli. Commercial washing processes for cantaloupes, utilizing sanitizing agents, are limited in their ability to inactivate and/or remove these human pathogens. We developed a commercial-scale surface pasteurization process for inactivating these pathogens on artificially contaminated cantaloupes. Whole cantaloupes, surface inoculated with Salmonella or Escherichia coli, were stored at 4 degree C or room temperature (RT) for up to 72 h prior to processing. Surface pasteurization at 76 degree C for 2-3 min at 24 h post inoculation resulted in 99.999% reduction in the pathogen populations. Cantaloupes that were surface pasteurized and stored at 4 degree C for 21 days retained their firmness qualities while non-treated controls became soft. These results indicate that surface pasteurization will enhance the microbiological safety of cantaloupes and will extend the shelf life of this commodity as well. These findings will assist food industry and regulatory agencies in establishing processing guidelines to guard against pathogens, thereby decreasing the incidence of food poisoning outbreaks.

Technical Abstract: Cantaloupes have been implicated in numerous foodborne outbreaks due to contamination with Salmonella Poona. Commercial washing processes for cantaloupes are limited in their ability to inactivate and/or remove this human pathogen. Our objective was to develop a commercial-scale surface pasteurization process for enhancing microbiological safety of cantaloupes. Populations of indigenous microflora recovered from cantaloupes that were surface pasteurized at 96, 86, or 76 degree C for 2-3 min were significantly (p<0.05) lower than those of the controls. Whole cantaloupes, surface inoculated with S. Poona RM 2350 or Escherichia coli ATCC 25922 to a final cell concentration of ca. 5 log10 CFU/cm2 were stored at 4 degree C or room temperature (RT) for up to 72 h prior to processing. Treatments at 76 degree C for 2-3 min at 24 h post inoculation resulted in excess of 5 log CFU/cm2 reductions in S. Poona and E. coli populations. Cantaloupes that were surface pasteurized and stored at 4 degree C for 21 days retained their firmness qualities and had no visible mold growth, as compared to the controls that became soft and moldy. These results indicate that surface pasteurization will enhance the microbiological safety of cantaloupes and will extend the shelf life of this commodity as well. Storage of untreated inoculated cantaloupes at RT for 24 to 72 h post inoculation caused a significant (p<0.05) increase in S. Poona and E. coli populations as compared to storage at 4 degree C. This indicates that cantaloupes should be refrigerated as soon as possible following harvesting to suppress the growth of any possible contaminant on the rind.

Last Modified: 9/1/2014
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