A study of bacteriocinogenic Lactobacillus sakei 268 antimicrobial activity in the presence of NaCl and NaNO2

ALVAREZ O.; C. HERMAN; CAYRÉ, M.E.; CASTRO M.; GARRO, O.A.; VIGNOLO G.M.

Foz do Iguazú

Congreso; XVI World Congress of Food Science and Technology; 2012

IUFOST

Food preservation using in situ bacteriocin production requires an adequate knowledge of the relationship between cell growth and bacteriocin production as a function of the intrinsic and extrinsic factors that prevail in the food matrix. The aim of this work was to evaluate the combine effect of NaCl and NaNO2, under refrigeration, on the antimicrobial activity of Lactobacillus sakei 268, a strain that showed good properties as a bioprotective culture in cooked meat products. A central composite design (22 + star) was applied, being the independent variables: NaCl concentration (0.2, 1, 3, 5 and 5.8 % w/v) and NaNO2 concentration (6, 35, 105, 175 and 204 mg/L). Cell growth was tested on MRS broth supplemented with the aforementioned additives. Antimicrobial activity against Staphylococcus aureus was carried out by means of the agar well diffusion assay (AU/ml). Time needed to reach the highest antimicrobial activity was used as response variable. Analysis of results indicated that the linear effect of NaCl and the quadratic effects of NaCl and NaNO2 had a significant effect on response variable. Among the latter effects, the influence of NaNO2 resulted less pronounced when compared to NaCl. The interaction effect between NaCl and NaNO2 was significant indicating that high NaCl concentrations together with high NaNO2 concentrations have a greater impact on time than with low NaNO2 concentrations. The results suggest that the effectiveness of Lb. sakei 268 as a protective culture for cooked meat products could be affected by NaCl and NaNO2 concentrations inherent in these products.