Eect of nisin and its combination with sodium chloride on the survival of Listeria monocytogenes added to raw bualo meat mince

Antilisterial activity of nisin (Nisaplin), alone at concentrations of 400 and 800 IU/g and in combination with 2% sodium chloride was incorporated in raw bu€alo meat mince. Samples of the raw meat mince were inoculated with 10 colony forming units (cfu)/g of L. monocytogenes and stored at 4 C for 16 days and at 37 C for 36 h. Initial estimates of pH, extract release volume, mesophilic and psychrophilic counts were found to be 5.74, 48 ml, 3.5 10 and 1.0 10 cfu/g of meat, respectively. The growth of L. monocytogenes in the treated groups was signi®cantly (P<0.05) inhibited compared to the control group. The degree of inhibition increased with increasing concentration of nisin and decreasing storage temperature. Addition of 2% sodium chloride in combination with nisin increased the ecacy of nisin at both storage temperatures. The pH in the treated groups remained signi®cantly lower (P<0.01) than in the control groups at both 4 and 37 C. # 2000 Elsevier Science Ltd. All rights reserved.