Control of Food-Borne Pathogens in Pre- and Post-Harvest Environments

NON-TECHNICAL SUMMARY: Contamination of poultry, meat and fresh produce with pathogenic bacteria is a significant concern for consumers and food service operators. While good agricultural practices and food safety measures can reduce the likelihood of foodborne pathogens entering the food supply, steps taken in food processing environments represent the final opportunity to mitigate risk prior to products entering the market. Studies will be targeted towards novel and natural strategies to control or eliminate foodborne bacterial pathogens in foods and food processing environments. Various antimicrobial systems and sanitizing agents designed to kill bacterial pathogens will be investigated and validated for treatment of food or food contact surfaces. Efforts will be made to develop and validate natural antimicrobial treatments which cause significant log-reductions of bacterial pathogens without imparting a significant change in the organoleptic properties of foods treated. Efficacy and feasibility of these treatments for food service operations to ensure food safety will also be evaluated. Physiological and genetic response of pathogens will be measured and compared in efforts to understand the mechanisms of action of antimicrobials and the potential for bacteria to resist treatments.<P>APPROACH: Foodborne bacterial pathogens such as Salmonella spp. and Listeria monocytogenes have unique abilities to persist in foods and food processing environments. Salmonella employs various genetic responses to stress that permit survival in conditions of extreme acid, alkali, heat, dessication, and sanitizer. L. monocytogenes is physiologically adapted to grow in cold environments and therefore grows in refrigerated food processing environments and on refrigerated foods. Both pathogens can be controlled through various hurdle technologies and are sensitive to various antimicrobial compounds and sanitizing agents if used optimally. Due to food matrices, food processing environmental conditions, or other factors, antimicrobial treatments are not always optimally applied. Studies are needed to validate the efficacy of existing antimicrobials and sanitizers against persistent strains of these pathogens. Genetic responses of these and other microorganisms to existing interventions will be studied in order to better understand mechanisms of action and strategies employed by bacteria that can provide resistance. Novel and natural antimicrobial and sanitizing technologies need development in order to provide other approaches to controlling these and other pathogens in foods and food processing environments. Naturally occurring plant, animal, and microbial antimicrobial compounds will be combined with various food-grade, GRAS chemicals in attempts to develop novel systems for use in food. Inoculated poultry, fresh produce and other food products will be treated with those novel and natural antimicrobial and sanitizing technologies at various treatment conditions to determine their efficacy to ensure food safety. Modeling of chilling and cooking of poultry and other food products will also be conducted to predict the lethality of selected pathogens at various processing conditions.