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

Non-Technical Summary: Historically, surrogate and indicator microorganisms have been used to study and predict the presence or fate of pathogenic microorganisms in the environment. Polystyrene microspheres may also be useful in studies of the transmission, movement, attachment, and detachment of pathogenic microorganisms to or from foods and food-contact surfaces. Since a population of microspheres cannot change biologically, they could be advantageous in studies that have a goal of determining the fate of microorganisms in a food process or for quantitative analyses. The purpose of this study is to evaluate the use (fluorescent) microspheres as surrogates for Salmonella Typhimurium in recovery studies from a food-contact surface such as stainless steel. <P> Approach: A. Determine the optimum recovery method for inoculated Salmonella Typhimurium, from stainless steel, using a rinse, non-contact sonication, and a one-ply composite tissue swab method. 1. Acquisition and preparation of a fluorescent labeled S. Typhimurium-GFP culture 2. Preparation and inoculation of stainless steel coupons 3. Quantify S. Typhimurium from steel coupons using three different recovery methods. 4. Quantify S. Typhimurium attached to steel coupons by confocal microscopy B. Determine the optimum recovery method of fluorescent microspheres, from stainless steel, using a rinse, non-contact sonication, and a one-ply composite tissue swab method. 1. Determine fluorescent microspheres for study 2. Determine enumeration procedures for microspheres from solution 3. Preparation and inoculation of stainless steel coupons 4. Quantify microspheres from steel coupons using three different recovery methods. 5. Quantify microspheres attached to steel coupons by confocal microscopy C. Compare both the quantitative recovery of Salmonella Typhimurium and fluorescent microspheres from, and quantitative attachment to, stainless steel.