Controlling Listeria Monocytogenes in Further Processed Meat

APPROACH: Commonly used marinade ingredients will be applied alone and in combination as additions to raw product formulation or as post cook dip. Marinade treatments for formulation will include: a) 1. 5% sodium chloride and 0.45% sodium tripolyphosphate, b) 2% sodium lactate, c) 2% potassium lactate, d) 0.75% sodium citrate and e) 2% sodium lactate with 0. 25% sodium diacetate. Marinades will be added to product during simulated commercial formulation and production. Sectioned product will be inoculated with a cocktail of L. monocytogenes strains. Product will be held at a refrigerated temperature or an abuse temperature; samples will be collected periodically and quantitatively cultured for L. monocytogenes. Paired uninoculated samples will be used for consumer acceptability measurements including color, moisture pickup, pH, cook loss, texture and sensory evaluation. A similar plan will be followed for the post cook application with the following treatments: a) 3.6% sodium lactate, b) 3.6% potassium lactate, c) 0.75% sodium citrate, d) 3.6% sodium lactate with 0.25% sodium diacetate and e) 3.6% sodium lactate, 3. 6% potassium lactate and 0.25% sodium diacetate as a dip. In this study, treatments will be applied after inoculation and samples will be quantitatively cultured for L. monocytogenes during refrigerated storage. <P>PROGRESS: 2005/10 TO 2006/09<BR>
Progress Report 4d Progress report. This is a subordinate project to Project Number: 6612-41420-015-00D, Microbial Ecology of Human Pathogens Relative to Poultry Processing. Listeria monocytogenes is a pathogen that can have serious consequences on the health of an infected person. The pathogen is commonly passed to humans by food. L. monocytogenes can contaminate poultry and beef further processing plants. This can result in accidental contamination of fully cooked ready-to-eat meat products. Some commonly used marinade ingredients can inhibit bacterial growth or even lower numbers of bacteria. We are undertaking a project whereby such ingredients including sodium tripolyphoshate, sodium lactate, sodium diacetate and sodium citrate are being included into product formulations in an effort to control the growth of L. monocytogenes. For this project a marked strain of L. monocytogenes will be used to experimentally inoculate product and counts of the bacteria will be made that do not include any background flora. Antibiotic resistant marked presumptive cultures of L. monocytogenes were obtained. Upon close examination these were found to not be L. monocytogenes. New L. monocytogenes cultures were obtained and are now being selected for an antibiotic resistant marker. Formulations have been calculated for beef frankfurters, turkey deli loaf and ham deli loaf that include all combinations of marinade ingredients. It is expected that the inoculated studies will begin very shortly. If treatment of foods with these products inhibits Listeria then they can provide a very practical and economic intervention method.