In‐package Pasteurization Combined with Biocide‐impregnated Films to Inhibit Listeria monocytogenes and Salmonella Typhimurium in Turkey Bologna

The inhibitory effects of in‐package pasteurization (3–5D, decimal reduction times) combined with a nisin (7%, w/w) containing wheat gluten film were tested over an 8‐wk storage period against Listeria monocytogenes and Salmonella Typhimurium populations inoculated on refrigerated bologna. Bologna slices subjected to the in‐package pasteurization process reducedL. monocytogenes populations 3.8‐ to 7.0‐log colony‐forming units (CFU)/g, and the remaining population fluctuated between 1.2‐ and 38‐log CFU/g over the 2‐mo storage period. S . Typhimurium was reduced 5.7‐ to 7.3‐log CFU/g, and the remaining population progressively declined from 100 to <10 CFU/g over 2 mo of storage. The wheat gluten film containing nisin was effective in reducing the population of L. monocytogenes (2.75‐log reduction with pasteurization; 1‐log reduction without pasteurization), but was not effective against S . Typhimurium (<1‐log reduction). Combining both treatments significantly reduced the L. monocytogenes populations and prevented outgrowth over the 2‐mo storage period but provided no added inhibitory effect against S . Typhimurium compared with only pasteurization.