Antimicrobial properties of probiotic bacteria from various sources

Abstract

The probiotic potentials of lactic acid bacteria species isolated from various food sources (nono, ugba, ogiri, kunun-zaki and ogi) were studied. The predominant species among the isolated strains were Lactobacillus bulgaricus, Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus brevis, Streptococcus thermophilus Leuconostoc mesenteroides and Pediococcus cerevisiae. They produced bacteriocins that inhibited the growth of Streptococcus aureus, Escherichia coli and Bacillus cereus. L. bulgaricus and L. plantarum were selected for the fermentation of vegetable substrates-carrot, cucumber and tomatoes and cereals-rice and maize for the purpose of studying the suitability of these raw materials for probiotic juice production. The fermentations were carried out at 30°C for 72 h. The lactic acid bacteria had viability counts of 10⁹ during storage at 4°C. The minimum pH attained during fermentation of samples was 3.9. The best bacteriocin preservative effect of 90% was observed in maize.

Key words: Lactic acid bacteria, tolerance, biotechnological properties, bile, ethanol.