Objective:  The effects of ingredients and other technological factors, e.g. salt, nitrite, water activity and fat, on the functionality of Lactobacillus sakei Lb 706 were investigated in order to evaluate bacteriocin bioavailability during sausage processing.
Methodology and results: A series of in vitro fermentation experiments were performed with varying concentrations of NaCl, NaNO2, glycerol and meat fat particles.NaCl and NaNO2 interfered with bacterial cell growth and bacteriocin activity. The growth of L. sakei Lb 706 was enhanced in the presence of low concentrations of NaCl (≤ 0.5%), though inconsistently, while high concentration (≥ 4%) of NaCl consistently inhibited growth.  NaNO2 had an insignificant effect on bacteriocin activity. At higher sodium nitrite concentration, sakacin A diminished accompanied with lower cell masses
Conclusions and application of findings: The use of L. sakei Lb 706 as a bacteriocin-producing culture during sausage processing is promising and can be used as a bioprotective culture against Listeria spp. The concentration of NaNO2 and NaCl may vary from 20 to 200 ppm and 2.5 to 3%, respectively, depending on the type of sausage and on regulatory requirements. The restrictive and inhibitory effects of nitrite, salt and fat on the growth of bacteria investigated were not very marked, and there were no significant differences between the separate or combined action of salt and nitrite. Although all experiments were conducted in a model system, these findings will aid in industrial implementation of efficient bacteriocin-producing protective cultures of L. sakei in meat production. These bacteriocinogenic protective cultures will contribute to meat products that are safer and of more consistent quality.

Key words

Lactobacillus sakei, sakacin A, cell activity, Sodium chloride, Sodium nitrite

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