Nisinogenic LAB strains seeded in the matrix Antibacterial Activity in the 20h pasteurized neutralized cell-free culture supernatants for the different matrix (AU/ml) MRS MS MSSM Lactococcuslactis subsp. lactis CWBI-B1410 80 ± 00 0 40 ± 00 Lactococcuslactis subsp. lactis CWBI-B1426 60 ± 28 0 40 ± 00

a (MRS): Man, Rogosa and Sharpe broth used as reference b(MS): Millet flour and salt (NaCl) in distilled water at the ratio [(2 + 0.5): 100 (w/v)] c(MSSM): Millet flour and salt (NaCl) in distilled water at the ratio [(2+ 0.5): 100 (w/v)] followed by supplementation of the sterilized resulting solution with pasteurized skimmed milk at the ratio 1:9 (v/v) *Nisin is a heat stable antibacterial peptide produced by some Lactococcus lactis strains (10, 25, 26), and the antibacterial activity was assessed by critical dilution in using a Listeria monocytogenes strain as indicator bacterium “0” means lack of inhibitory action of the neutralized culture supernatant.

Table 3: Anti-Listeria monocytogenes activity in the heated neutralized cell -free supernatants of 20h at 30°C incubated standard mediuma and millet based substratesb,c seeded with revitalized nisinogenic* Lactococcus lactis subsp. lactis CWBI_B1410 or Lactococcus lactis subsp. lactis CWBI_B1426. The data are the mean ± standard deviation from duplicate trials performed on different samples at different times.