Survival of Listeria monocytogenes and Salmonella Typhimurium in Pepperoni With Reduced Salt and Sodium Nitrite Levels, and Sublethal Thermal Treatments

ABSTRACT There is increasing pressure to reduce sodium nitrite and salt levels in processed and fermented meats in response to consumer demands and updated legislation. However, such reductions may impact pathogen control. In this study, the survival of Listeria monocytogenes and Salmonella Typhimurium was evaluated in pepperoni produced with reduced salt and sodium nitrite levels, with or without an enhanced postfermentation thermal treatment. Pepperoni batters with formulations varying in sodium nitrite (50–150 ppm) and salt (1.4%–2.5%), were inoculated with cocktails of L. monocytogenes or S. Typhimurium (~log 10 4–6 CFU g −1 ), subjected to a postfermentation thermal treatment (53.5°C × 61 min; 61°C × 40 min; 64°C × 20 min), and dried to a target water activity of 0.91 or 0.94. Overlay plating was used to enumerate both pathogens, allowing recovery of sublethally injured cells, and residual nitrite was also measured. In the standard formulation reductions of log 10 4.47 CFU g −1 for L. monocytogenes and log 10 4.18 CFU g −1 for S. Typhimurium were observed from prefermentation to endpoint. Formulation 1a, which differed from the standard formulation only in having a lower sodium nitrite level (50 ppm), showed endpoint reductions of log 10 4.21 CFU g −1 for L. monocytogenes and log 10 4.58 CFU g −1 for S. Typhimurium. A similar trend was observed in formulations with reduced sodium nitrite and salt levels. However, formulations subjected to the elevated thermal treatment (61°C × 40 min) showed greater endpoint reductions in both L. monocytogenes and S. Typhimurium compared with formulations processed at 53.5°C × 61 min. Residual nitrite levels at endpoint were well below legal limits across all recipes, reflecting extensive nitrite depletion during fermentation, heating, and drying. These findings demonstrate that pepperoni can be manufactured safely with reduced sodium nitrite and salt when a validated, postfermentation heat treatment is incorporated within a multihurdle system, supporting the feasibility of reformulation under current consumer and regulatory pressures.