Effect of Lactic Acid on Inactivation of Enterotoxigenic Escherichia Coli (ETEC) Isolated from Tuna Loins Produced in Côte D’Ivoire

Abstract

Aims: The aim of this work was to study the effect of lactic acid on the growth of pathogenic strains of Escherichia coli (ETEC) isolated from tuna loins. Study Design: Bacteriological study. Place and Duration of Study: Laboratory of Microbiology of the Central Laboratory of Food hygiene and Agrobusiness (LCHAI), Abidjan, Côte d’Ivoire between September 2014 and December 2014. Methodology: Enterotoxigenic Escherichia coli (ETEC) strains were isolated from tuna loins. Lactic acid (LA) 1%, 2% and 3% were tested in pathogenic strains in liquid medium (brain heart infusion broth, BHI) and in tuna loins. Results: At lactic acid 1%, the bacterial loads decreased during the first two days and then stabilized. E. coli strains in tuna loins were higher (1.25 to 0.9 log CFU/g) than E. coli in liquid medium (0.69 to 0.3 log CFU/g). No bacterial growth was observed in the tuna loins and in BHI for concentrations of 2% and 3% of lactic acid. Conclusion: Lactic acid has an inhibitory effect at 1% and bactericidal effect at 2% and 3% on the growth of E. coli. The use of lactic acid as a preservative could be a solution for the preservation of these products.