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United States Department of Agriculture

Agricultural Research Service

Title: Thermal Inactivation of Salmonella on Cantaloupe Using Hot Water

Authors
item Solomon, Ethan
item Sites, Joseph
item Huang, Lihan
item Annous, Bassam

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 10, 2005
Publication Date: July 15, 2005
Citation: Solomon, E.B., Sites, J.E., Huang, L., Annous, B.A. 2005. Thermal inactivation of salmonella on cantaloupe using hot water (abstract). Institute of Food Technologists. Available:http://ift.confex.com/ift/2005/techprogram/paper_30545.htm

Technical Abstract: Cantaloupes have been implicated in six outbreaks of salmonellosis in the U.S. since 1990. In response to three recent outbreaks, the FDA issued an import alert detaining all cantaloupes originating in Mexico. Numerous sanitizing treatments for cantaloupe have been investigated, but have shown limited efficacy. Surface-pasteurization of cantaloupes has been demonstrated to be a viable alternative to chemical sanitizers. Previous work in our laboratory has shown that specific time/temperature combinations are capable of reducing levels of Salmonella on inoculated cantaloupes. Our objective was to use a newly fabricated processing vessel to validate the effects of hot water treatments on levels of Salmonella on cantaloupes. Cantaloupes were inoculated (ca. 105 log CFU/cm2) and held at 4 degree C overnight to allow for strong bacterial attachment. Melons were submerged into water within the processing vessel (heated to 65, 75, or 85 degree C) for 10, 30, 60, and 90 seconds. Melons were then removed, placed on ice, and peeled for microbiological analysis. Levels of Salmonella were determined by surface plating on TSA, followed by overlaying with XLT-4. Our results indicated that at 65 degree C, a treatment time of 90 seconds was required to reduce the population of Salmonella by approximately one log. Ninety second treatments eliminated 3.3 log CFU/cm2 at 75 degree C, and 4.5 log CFU/cm2 at 85 degree C. None of the treatments had any apparent effect on the texture of the melon. Heat penetration analysis indicated that the flesh of the melon remained relatively cool throughout the thermal process. These results underscore the viability of surface pasteurization as a method to inactivate Salmonella on the surface of cantaloupe. This process could be adapted for the treatment of melons prior to preparation of fresh-cut pieces. Computer simulation will be used to determine the minimum heating requirements for pasteurizing melons using this technology.

Last Modified: 10/23/2014
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