In Vitro and In-Model Evaluation of the Antimicrobial Activity of Lactic Acid Bacteria Protective Cultures to Replace Nitrite in Dry Fermented Sausages

When investigating substitutes for nitrate and nitrite in meat products, it is essential to assess whether these alternatives have the same antimicrobial effect as the curing salts to be fully or partially replaced. Challenge tests on real products require a considerable amount of time and expense, and it is necessary to have precise information on the activity and viability of the compounds/ingredients to be investigated to carry out those tests. Here we describe the protocol for conducting in vitro (using agar diffusion test) and meat model studies with bacteriocin-producing lactic acid bacteria cultures to replace nitrite in fermented sausages, before proceeding to in-product challenge tests. We describe the protocol to investigate antilisterial activity, but it can be applied to other non-spore-forming meat pathogens. With some modifications, this protocol could also be adapted to test antimicrobial ingredients other than bacteriocin-producing cultures.