Antimicrobially active lactobacilli from goats’ milk that do not produce biogenic amines

Strains of lactobacilli isolated from goats’ milk, namely, Lactobacillus casei 21L10, Lactobacillus johnsonii KB2-1 and Lactobacillus plantarum 25/1L, were tested for antimicrobial activity and production of biogenic amines. Lb. johnsonii KB2-1 accumulated hydrogen peroxide (6.29 mg•ml-1). No strain produced acetic acid. Strains Lb. casei 21L10 and Lb. johnsonii KB2-1 converted glucose into lactic acid at highest levels (19.84 g•l-1 and 19.89 g•l-1, respectively) after 48 h of cultivation, but specific production rates were the highest for Lb. johnsonii KB2-1 (1.42 g•l-1•h-1) and Lb. plantarum 25/1L (1.50 g•l-1•h-1). Lb. johnsonii KB2-1 and Lb. plantarum 25/1L were more efficient producers of phenyllactic acid (116.63 mg•ml-1 and 108.40 mg•ml-1, respectively) than Lb. casei 21L10 (66.43 mg•ml-1) after 72 h of cultivation. All strains considerably inhibited undesirable moulds, and Lb. casei 21L10 and Lb. plantarum 25/1L even more significantly inhibited undesirable and pathogenic bacteria. None of the strains produced putrescine, tyramine or histamine, while cadaverine was produced only by Lb. johnsonii KB2-1 on a low level (8.47 mg•l-1). Antimicrobial effects of these lactobacilli, which produce low amounts of biogenic amines, may prevent formation of biogenic amines by contaminating microorganisms in milk processing.