Impact of nitrite reduction in cooked turkey ham: preliminary studies on safety issues

Sodium nitrite is a preservative widely used in the meat industry to ensure product quality and safety by inhibiting the growth of pathogenic microorganisms and preventing spoilage. Cooked turkey ham commonly contains nitrite; however concerns regarding its potential health effects have prompted regulatory changes in Europe, reducing the maximum permitted level from 150 mg/kg to 80 mg/kg (expressed in nitrite ions, corresponding to 119 mg/kg of sodium nitrite) in meat products. This study aimed to evaluate the impact of nitrite reduction on the microbiological safety and organoleptic characteristics of cooked turkey ham.

Total viable counts (TVC), lactic acid bacteria (LAB), Enterobacteriaceae, Escherichia coli, and Staphylococcus aureus as well as pathogenic bacteria, including Listeria monocytogenes, Salmonella spp., and sulphite-reducing Clostridium spores, were determined according to ISO standards in cooked turkey ham produced with different nitrite concentrations throughout its shelf life. Physico-chemical analysis, including colour, water activity (a_w) and pH were evaluated at 0, 17, and 35 days of storage. Challenge testing was performed with both L. monocytogenes and C. sporogenes (as a surrogate for C. botulinum), during 35 and 264 days, respectively, under refrigerated storage (4 ºC) and abuse storage temperature (8 ºC).

Microbiological analyses demonstrated that the reduced-nitrite product showed trends in TVC and LAB growth similar to those of the standard product, with counts remaining below 1.0 x 10⁷ CFU/g throughout 28 days of storage at 4 °C and no detection of pathogenic bacteria, in line with microbiological safety criteria. Overall, no significant differences were observed in physico-chemical properties during the shelf life of the product. Challenge testing results indicate that the reduced-nitrite formulation limited the growth of L. monocytogenes remaining below the 0.5 log CFU/g threshold at 4 °C but showing an increase above this threshold at 8 °C, and prevented vegetative outgrowth of C. sporogenes under the tested conditions.

These findings suggest that nitrite reduction does not adversely affect the safety or quality of cooked turkey ham under the conditions studied. Nevertheless, additional research is required to further confirm the long-term safety of reduced-nitrite formulations.