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United States Department of Agriculture

Agricultural Research Service

Research Project: INTERVENTION TECHNOLOGIES FOR MINIMALLY PROCESSED FOODS

Location: Food Safety and Intervention Technologies

Title: Commercial thermal process for inactivating Salmonella Poona on surfaces of whole fresh cantaloupes

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

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 29, 2012
Publication Date: January 2, 2013
Citation: Annous, B.A., Burke, A.M., Sites, J.E., Phillips, J.G. 2013. Commercial thermal process for inactivating Salmonella Poona on surfaces of whole fresh cantaloupes. Journal of Food Protection. Volume 76(3):420-428.

Interpretive Summary: Cantaloupe melons have been implicated in at least seven outbreaks of Salmonella and one outbreak of Listeria monocytogenes, and resulting in more than 36 deaths since 1990. These outbreaks indicate that cantaloupes are a high risk commodity. Our laboratory has investigated a variety of treatments for sanitizing melons, concluding that aqueous sanitizers were only partially effective at reducing populations of Salmonella, especially when the target bacteria were allowed to reside on the melon surface for more than 24 hours. Recently, our laboratory has focused on the use of hot water as a simple intervention to inactivate surface associated bacteria. The goal of the current research was to demonstrate the efficacy of hot water surface pasteurization at 92 deg C for 90 s for the inactivation of Salmonella and compare to efficacy of various chlorine and experimental sanitizer solutions. Results confirmed that in excess of 99.999% reduction of pathogen populations could be obtained. These results indicate that surface pasteurization will enhance the microbiological safety of this commodity. These findings will assist food industry and regulatory agencies in establishing processing guidelines to guard against pathogens, thereby decreasing the incidence of illness outbreaks.

Technical Abstract: Outbreaks of salmonellosis by Salmonella Poona and listeriosis by Listeria monocytogenes have been associated with the consumption of cantaloupes. Commercial washing processes for cantaloupes are limited in their ability to inactivate and/or remove these human pathogens. Our objective was to develop a commercial-scale surface pasteurization process for enhancing microbiological safety of cantaloupes. Whole cantaloupes, surface inoculated with S. Poona RM 2350 were stored at 32 deg C for 24 h prior to processing. Hot water treatments at 92 deg C for 60 and 90 s inactivated in excess of 5 log reductions in S. Poona. Cantaloupes that were treated and stored at 4 deg C for 9 days retained their firmness-quality and maintained non-detectable levels of S. Poona as compared to the controls. Also, levels of S. Poona on fresh-cut cantaloupe prepared from treated cantaloupes and stored for 9 days at 4 deg C were non-detectable as compared to the controls. Temperature penetration profiles indicated that the surface temperature of the whole cantaloupe was 26-30 deg C below the wash water temperature. These results indicate that surface pasteurization at 92 deg C for 90 s will enhance the microbiological safety of cantaloupes and will extend the shelf life of this commodity as well. The process parameter of 90 s or less falls within the commercial requirements of the whole cantaloupe processors/packers industry.

Last Modified: 9/23/2014
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