A case study on microbiological properties of cooked turkey ham with nitrite reduction

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Cooked turkey ham is a widely consumed ready-to-eat meat product in which nitrite plays an important role in safety and quality. However, growing health concerns and regulatory constraints have driven efforts to reduce nitrite use. This study evaluated the effect of reducing nitrite levels from 150 to 119 ppm on the microbiological safety and physicochemical stability of cooked turkey ham during refrigerated storage. Microbiological quality was monitored at 7-day intervals, including total viable counts (TVC), lactic acid bacteria (LAB), Enterobacteriaceae , Staphylococcus aureus , and Escherichia coli . TVC and LAB remained below 10 7 CFU/g until day 28 but reached unsatisfactory results on day 35 (10 8 CFU/g), whereas the remaining microbial groups remained below the detection limit throughout storage, thus supporting a commercial shelf life of 28 days. Sulphite-reducing Clostridium spores, Salmonella spp., and Listeria monocytogenes were not detected in any samples. Challenge tests with Listeria monocytogenes and Clostridium sporogenes were conducted under refrigerated storage and temperature abuse conditions (8 °C) for up to 35 and 264 days, respectively. The reduced-nitrite formulation limited the growth of L. monocytogenes , remaining below the 0.5 log CFU/g threshold at 4 °C but showing a transient increase above this threshold at 8 °C, and prevented detectable vegetative outgrowth of C. sporogenes under the tested conditions. Colour parameters showed no significant differences between the standard and reduced-nitrite formulations (P > 0.05). Physicochemical parameters showed small changes during storage time but remained within the acceptable ranges, with pH values ranging from 6.0 to 6.3, water activity (a w ) ranging from 0.94 to 0.96. Overall, the results indicate that reducing sodium nitrite to 119 ppm in the tested cooked turkey ham formulation is feasible without compromising microbiological safety or technological functionality during the defined 28-day commercial shelf life under the conditions evaluated.