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<OL> <LI> To determine the parameters for the application of ultraviolet light and ozone in combination with either dimethyl dicarbonate, hydrogen peroxide or citric acid necessary to reduce populations of Listeria monocytogenes in recycled chill brines. <LI> To determine the parameters for the application of chemical treatments (lactic acid, chitosan, and casein hydrolysates) and physical interventions (steam and hot water pasteurization), as well as combinations of chemical and physical treatments necessary to reduce populations of Listeria monocytogenes on frankfurters. <LI> To develop course modules that convey research findings to students in graduate level advanced food microbiology courses, and to contribute to the graduate education of those students involved in the performing research activities related to the project. <LI> To integrate research observations with training approaches to enhance practices among meat processors with the goal of increasing product safety.
NON-TECHNICAL SUMMARY: Ready-to-eat (RTE) meats have been associated with outbreaks of foodborne illness caused by Listeria monocytogenes. Contamination RTE products often occurs after processing but prior to packaging. This project seeks to determine appropriate measures for the control of Listeria monocytogenes in chill brines and on frankfurters.
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APPROACH: Objective 1: Chill brines will be inoculated with Listeria monocyotgenes and then exposed to ultraviolet light alone or in combination with ozone in a recycling treatment system. Chemical preservatives (dimethyl dicarbonate, hydrogen peroxide, and citric acid) will be added to chill brines in conjunction with UV and ozone treatment. The preservatives will be added to chill brines prior to and after UV/ozone treatment to determine the combined effect on the survival of L. monocytogenes. At appropriate times, portions of the test brine will be analyzed for surviving populations of L. monocytogenes using a modification of USDA protocol. <P>
Objective 2: Frankfurters obtained from a commercial processor will be surface inoculated with Listeria monocytogenes and treated with lactic acid, chitosan and casein hydrolysates. Treated frankfurters will be vacuum packaged and stored under refrigeration. At appropriate times, samples will be analyzed for L. monocytogenes as noted above. Inoculated, packaged frankfurters will be submerged in a hot water bath or placed into a steam tunnel and heated to a core temperature of 80 to 90 degrees celsius. Combination treatments of antimicrobial agents (lactic acid, chitosan, and casein hydrolysates) and hot water or steam treatment will be performed as well. The investigators will develop course modules that convey research findings to students in graduate level advanced food microbiology courses, and contribute to the graduate education of those students involved in the performing research activities related to the project. Finally, the invesitgators will interpret and provide research observations to meat processors and regualtory agencies through workshops, extension publications and roundtable discussions.