Addition of 2.5% lactate and 0.25% acetate controls growth of Listeria monocytogenes in vacuum-packed, sensory-acceptable servelat sausage and cooked ham stored at 4°C

A study of the inhibitory effects of propylparaben and of a combination of lactate and acetate against growth of Listeria monocytogenes in inoculated liquid medium, sliced servelat sausage and cooked ham, were performed using rifampicin resistant Listeria strains in inoculation experiments. A consumer acceptance test of products produced with and without the compounds was also performed. Propylparaben was found to be effective in a model liquid non-fat medium, but was without effect in the actual products. This illustrates the potential pitfalls in translating results from studies in liquid media to fat-containing food products. The combined inhibitory and sensory results showed that a mixture of 2.5% lactate and 0.25% acetate (w/w, calculated on the water phase), could be used to increase the margins of safety for sliced and spreadable vacuum-packed ready-to-eat cooked meat products stored for 4–6 weeks. In addition, strict control of temperature during production and storage is very important.