Sodium chloride reduction in meat processing: Microbial shifts, spoilage risks, and metagenomic insights

This review evaluated the impact of sodium chloride (NaCl) reduction or substitution on the microbial ecology of meat products, with a focus on how these changes affect shelf life and safety. Reducing NaCl in fresh meat products promotes the growth of psychrotrophic spoilage bacteria, such as Pseudomonas sp., which thrive at low temperatures, and mesophilic pathogens like Escherichia coli and Staphylococcus aureus, particularly under inadequate storage conditions. In cured and fermented meats, such as salami, lowering NaCl levels disrupts the balance of salt-tolerant microorganisms, notably lactic acid bacteria (LAB) and coagulase-negative staphylococci, potentially leading to increased spoilage and pathogen proliferation. In smoked meats, the combination of reduced NaCl and altered microbial ecology, including a shift toward LAB dominance, may weaken the inhibitory effects on spore-forming bacteria like Clostridium botulinum. Additionally, using metagenomics, we explore the shifts in microbial communities observed in studies involving meat, revealing critical insights into the composition and diversity of bacteria in meat products, as well as the gaps in research on the impact of NaCl reduction and/or substitution on the microbiota. This review provides a comprehensive understanding of these microbial shifts, highlighting the distinct responses of psychrotrophic, mesophilic, and LAB groups to NaCl modification and the need to understand the effects of these alternatives on the meat product microbiome, as well as the neglected microorganisms that can affect the quality and safety of these products.