Growth and biogenic amine (histamine and tyramine) potential of probiotic Lactobacillus casei in skim milk.

摘要

The growth and biogenic amines (histamine and tyramine) potential of decarboxylase positive probiotic Lactobacillus casei (TISTR 389) was studied in skim milk. Fermentation was followed for 48 h at 37 degrees C and samples were analysed for pH, log CFU mL-1, percentage titratable acidity, proteolytic activity and histamine and tyramine. The maximum viable cell count 9.18 log CFU mL-1 was observed after 24 h of incubation. The past reduction of pH was observed with concomitant increased in acid production during the fermentation. Proteolytic activity was fairly constant between 18-24 h and showed increase after 48 h of incubation. Histamine to a level of 6.87+or-0.091 mg L-1 was detected after 24 h while tyramine level of 6.08+or-0.042 mg L-1 was detected after 48 h of incubation. Our study reveals that careful screening for amino acid decarboxylase activity is essential before selecting lactic acid bacteria as appropriate starter or probitic strains in dairy industry.