Investigation of Escherichia coli O157:H7 Survival and Interaction with Meal Components during Gastrointestinal Digestion.

Diane De La Pomelie,Véronique Santé-Lhoutellier,Régine Talon,Sabine Leroy,Philippe Gatellier,Philippe Ruiz

doi:10.3390/foods10102415

Abstract

Escherichia coli O157:H7 is responsible for foodborne poisoning, incriminating contaminated animal food and especially beef meat. This species can survive in the digestive tract, but, up to now, very few studies have considered its survival during the gastrointestinal digestion of meat. The present study aimed to investigate the survival of the pathogenic strain E. coli O157:H7 CM454 during the gastrointestinal digestion of ground beef meat and its interactions with meal components using a semidynamic digestive model. The CM454 strain in meat survived throughout digestion despite acidic pH (pH 2) and the presence of bile salts. The addition of nitrite and ascorbate in the digestion medium led to a decrease in strain survival. During digestion, a release of free iron was observed, which was accentuated in the presence of the CM454 strain. In addition, the strain modified the Fe2+/Fe3+ ratio, in favor of Fe2+ compared to the noninoculated meat sample. In the presence of nitrite, nitroso compounds such as nitrosamines, nitrosothiols, and nitrosylheme were formed. E. coli O157:H7 CM454 had no impact on N-nitrosation but seemed to decrease S-nitrosation and nitrosylation.

Highlights

Accepted: 8 October 2021Shiga toxin-producing Escherichia coli (STEC) are zoonotic agents that rank third among food-borne pathogens regarding their incidence and dangerousness in the European Union [1]
The meat was inoculated at 9.8 ± 0.2 log CFU/g by the E. coli O157:H7 CM454 strain, and after storage for 3 days at 4 ◦ C and 30 min at 20 ◦ C to reach 12 ◦ C, the enumeration was 8.6 ± 0.4 log CFU/g
The E. coli O157:H7 CM454 strain inoculated in ground meat could survive throughout digestion despite acidic pH

Summary

Introduction

Shiga toxin-producing Escherichia coli (STEC) are zoonotic agents that rank third among food-borne pathogens regarding their incidence and dangerousness in the European Union [1]. They are responsible for foodborne poisoning incriminating contaminated animal food products, vegetables, and watery drinks [1]. The consumption of bovine meat and products thereof accounted for 24% of epidemics caused by STEC in Europe in the period 2012–2017 [1]. According to an Ifop survey published in 2010, ground beef is considered the favorite meat product of children at 59% and can constitute a danger in the event of insufficient cooking (under 70 ◦ C) of contaminated meat [6]

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