Survivability of pathogenic Listeria monocytogenes against nisin and its combination with sodium chloride in raw buffalo meat mince

A study was conducted to examine the anti-Listeria monocytogenes activity of nisin (Ambicin N) alone at concentrations of 400, 800 and 1200 IU/g and in combination with 2 % sodium chloride incorporated in raw buffalo meat mince stored at 4 degreesC for 16 days and 37 degreesC for 36 h. Initial microbial analysis of meat mince revealed pH, extract release volume, mesophiles and psychrophiles count as 5.76, 49 ml, 33 x 10(4) and 15 x 10(4) cfu/g of meat, respectively. All the combinations of preservatives inhibited the count of L. monocytogenes significantly (P<0.05) at both the storage temperatures when compared to the control. Addition of 2 % sodium chloride increased the efficacy of nisin against L. monocytogenes in all the three combinations. The degree of inhibition was more at higher concentration of nisin and lower temperature, pH in treatment groups remained significantly lower than the control groups at 4<degrees>C (P<0.01) and 37<degrees>C (P<0.05). Results indicated that the combination of food grade preservatives could be an effective listeriostatic in minced meat.