Sodium reduction in cooked meat products without compromising microbiological safety: A predictive microbiology...

Sodium plays a critical role in the microbiological stability of cooked meat products, yet regulatory and consumer pressure to reduce sodium intake creates formulation challenges where safety margins are poorly defined. This study quantified the effect of sodium concentration (196-980 mg/100 g), pH, and water activity on the growth dynamics of lactic acid bacteria (Leuconostoc sp.) and Salmonella enterica serovar Typhimurium in a cooked meat analogue - designed to allow independent control of physicochemical variables - and integrated these relationships into a predictive microbiology framework for reduced‑sodium formulation design. Primary modeling using the Baranyi-Roberts model best described experimental growth curves, and secondary modeling via a modified Norrish equation quantified the effect of environmental factors on maximum specific growth rate (μ_max). Global sensitivity analysis identified μ_max and maximum population density as the dominant sources of variability in model predictions. Increasing sodium concentration significantly reduced μ_max in both organisms, with LAB exhibiting greater tolerance than Salmonella. Multi-criteria optimization identified ~500 mg sodium/100 g as the microbiologically safe optimum - representing a ~ 41% reduction relative to internationally comparable regulatory limits for cooked ham (846 mg/100 g)- while preserving inhibitory conditions against pathogens. Independent validation in cooked ham confirmed model accuracy with deviations below 5% for growth rate and 2% for shelf-life, predicting a shelf-life of ~18 days. This framework provides an organism-specific, quantitative basis for designing reduced‑sodium cooked meat products with defined microbiological safety margins, directly applicable to reformulation strategies in industry and regulatory contexts.