Growth and Survival of Enterotoxigenic Escherichia coli (ETEC) Isolated from Tuna Loins Produced in Côte D’ivoire

Aims: The aim of this study was to study the growth of pathogenic strains of Escherichia coli (ETEC) in Tuna loins.

Study Design: Bacteriological study.

Place and Duration of Study: Laboratory of Microbiology of the Central Laboratory of Food hygiene and Agro-business (LCHAI), Abidjan, Côte d’Ivoire between September 2014 and December 2014.

Methodology: Three strains of E. coli (enterotoxigenic strain of E. coli (ETEC), possessing both "elt" and "est" virulence genes resistant to amoxicillin from Tuna loins; E. coli reference strain (ATCC 25992); strain of E. coli (KO 13) from water with the virulence gene "elt") were inoculated in brain heart infusion broth (BHI) and in tuna loins for 120 hours. pH and bacterial loads of E. coli were measured to 0; 3; 6; 12; 24; 48; 72; 96 and 120 hours respectively.

Results: The results showed that the three strains of E. coli used in this work survived in liquid medium (BHI) and in Tuna loins even after 5 days (120 hours). The growth curves of these three strains evolved in the same way in liquid medium and in Tuna loins. However, the growth rate of strains of E. coli inoculated in liquid media (BHI) was higher than that of strains inoculated in Tuna loins.

Conclusion: Pathogenic strains of E. coli isolated from Tuna loins are a hazard to be considered in the microbiological risk assessment of the consumption of these Tuna products.