Combined effect of lactic acid bacteria and citric acid on Escherichia coli O157:H7 and Salmonella Typhimurium

Abstract

Lactic acid-producing bacteria (LAB) and organic acids can inhibit the growth of pathogenic bacteria and spoilage organisms. Here, synergistic effect of LAB and citric acid was examined. Escherichia coli O157:H7 or Salmonella Typhimurium were treated with a 1% citric acid, 2% citric acid, LAB mixture, LAB mixture+1% citric acid, and LAB mixture+2% citric acid for 10, 20, 30, and 60 min, respectively. While LAB only, the addition of 1 or 2% citric acid caused 0.28-0.57 log reductions of E. coli O157:H7 or S. Typhimurium within 60 min, the treatment of LAB mixture+2% citric acid showed 1.96 and 6.24 log reductions of E. coli O157:H7 and S. Typhimurium, respectively. In conclusion, LAB and citric acid act synergistically and the combination showed its potential of an effective hurdle for the inactivation of foodborne pathogens.