Investigation of the Possibility of Listeria monocytogenes Growth in Alternatively Cured Cooked Sausages—A Case Study

The aim of this study was to investigate the possibility of Listeria monocytogenes growth in cooked sausages produced in the same meat processing plant without or with a direct nitrite addition (alternatively cured, AC, and nitrite cured, control). The AC and control sausages were inoculated with a mix of three L. monocytogenes strains. Products (n = 24 sausages for each product type) were vacuum-packed and stored for 10 days at 6 °C. Residual nitrite and salt contents, water activity and the number of L. monocytogenes were determined in products. A higher nitrite content was found in the control (44.9 mg/kg) compared with AC (12.1 mg/kg). Significantly higher L. monocytogenes counts at the 6th and the 8th day were noted in AC sausages, however at the 10th day they did not differ significantly between the treatments (2.96 and 3.27 log10 CFU/g in the control and AC, respectively). AC sausages showed a growth potential value of 0.64, which indicates the possibility of L. monocytogenes growth on the surface of alternatively cured products. In contrast, a growth potential value of 0.21 was found in control sausages, which indicates that nitrite cured sausages did not support the pathogen growth at 6 °C.