Characterization of Escherichia coli from Edible Insect Species: Detection of Shiga Toxin-Producing Isolate.

Anja Müller,Nils T Grabowski,Birte Ahlfeld,Min Yue,Corinna Kehrenberg,Diana Seinige

doi:10.3390/foods10112552

Abstract

Insects as novel foods are gaining popularity in Europe. Regulation (EU) 2015/2283 laid the framework for the application process to market food insects in member states, but potential hazards are still being evaluated. The aim of this study was to investigate samples of edible insect species for the presence of antimicrobial-resistant and Shiga toxin-producing Escherichia coli (STEC). Twenty-one E. coli isolates, recovered from samples of five different edible insect species, were subjected to antimicrobial susceptibility testing, PCR-based phylotyping, and macrorestriction analysis. The presence of genes associated with antimicrobial resistance or virulence, including stx1, stx2, and eae, was investigated by PCR. All isolates were subjected to genome sequencing, multilocus sequence typing, and serotype prediction. The isolates belonged either to phylogenetic group A, comprising mostly commensal E. coli, or group B1. One O178:H7 isolate, recovered from a Zophobas atratus sample, was identified as a STEC. A single isolate was resistant to tetracyclines and carried the tet(B) gene. Overall, this study shows that STEC can be present in edible insects, representing a potential health hazard. In contrast, the low resistance rate among the isolates indicates a low risk for the transmission of antimicrobial-resistant E. coli to consumers.

Highlights

Edible insects are popular foods in many parts of the world such as Asia and Africa
In the European Union (EU), edible insects are included in the novel food regulation, Regulation (EU) 2015/2283, which lays the legal framework for placing novel foods on the European market
The European Food Safety Authority has already published a scientific opinion regarding the safety of dried yellow mealworm (Tenebrio molitor), which concluded that they are safe for human consumption [3], an important first step towards an approval for this species to be placed on the European market

Summary

Introduction

Edible insects are popular foods in many parts of the world such as Asia and Africa. In Europe, insects are still rarely consumed but are gaining in popularity. The European Food Safety Authority has already published a scientific opinion regarding the safety of dried yellow mealworm (Tenebrio molitor), which concluded that they are safe for human consumption [3], an important first step towards an approval for this species to be placed on the European market. The European commission has released the Commission Implementing Regulation (EU) 2021/882, authorizing the placing on the market of dried yellow mealworms as of 1 June 2021.

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