Inhibition of Staphylococcus Aureus in Buffer, Culture Media and Foods by Lacidin A, a Bacteriocin Produced by Lactobacillus Acidophilus Osu133

Thirty seven strains of lactobacilli and leuconostocs were screened for bacteriocin production. A bacteriocin‐like substance (designated lacidin A) was detected in culture filtrate of Lactobacillus acidophilus OSU133. Lacidin A inhibited Enterococcus faecalis, L. acidophilus, Lactobacillus delbrueckii subsp. lactis, and Staphylococcus aureus. The bacteriocinogenic nature of lacidin A was confirmed by eliminating the inhibitory effects of acid, hydrogen peroxide and phage and by loss of activity upon hydrolysis with proteolytic enzymes. The bacteriocin is relatively heat‐stable and has considerable bactericidal action against S. aureus in phosphate buffer. Lacidin A also demonstrated bacteriostatic action against S. aureus in brain heart infusion and heat‐treated milk and liquid whole egg.