Microbiological safety of industrially reared insects for food: Identification of bacterial endospores and targeted detection of foodborne viruses

Abstract

25Edible insects are characterised by high microbial numbers of which the bacterial endospores 26 fraction can survive thermal processing. It is unknown, however, which bacterial species occur 27 as endospore in edible insects and what impact they have on food safety. Additionally, edible 28 insects have never been explored for the presence of foodborne viruses so far. In this study, we 29 found that the bacterial endospore fraction in a collection of mealworm and cricket samples 30 obtained from commercial insect producers can comprise a large amount of Bacillus cereus 31 group members that can pose insect or human health risks. Monitoring and effective mitigation 32 of these risks are urged. By contrast, none of the foodborne viruses hepatitis A virus, hepatitis 33 E virus and norovirus genogroup II were detected in the sample collection. Therefore, food 34 safety risks originating from these viral pathogens can be concluded to be low. 35 Introduction 36 As from 2014, edible insects and insect-derived food products started to enter the 37 European markets. According to the International Platform of Insects for Food and Feed 38 (IPIFF), 6,000 tonnes of insect proteins were produced by its European members in 2019. The 39 organisation estimates production to be around 3 mio tonnes in 2030. Due to the expansion of 40 the insect sector risk assessments and food safety research regarding insects as a new food 41 matrix were initiated, e.g. by EFSA 1 . In the past five years, many basic microbiological food 42 safety questions were formulated and investigated, as reviewed by Garofalo et al. (2019) 2 . In 43 summary, freshly reared insects may be highly contaminated with diverse microorganisms. 44 Even though insects are not likely to be consumed in a raw status, it is important to know which 45 organisms should be targeted by heat and other processing treatments. It was demonstrated both 46 for fungi and bacteria for yellow mealworms (Tenebrio molitor) 3 , lesser mealworms 47 (Alphitobius diaperinus) 4 and tropical house crickets (Gryllodes sigillatus) 5 that high numbers 48 of these microorganisms can easily be reduced, e.g. by applying a mild heat treatment.. 49 However, it was repeatedly observed that a fraction of the bacteria, i.e. the endospores, can 50 survive those mild heat treatments 3,6 . Bacillus and Clostridium are two relevant bacterial genera 51 that are able to produce endospores. Since several members of these genera are food pathogens 52 (e.g. B. cereus, C. perfringens, C. botulinum), the survival of endospores in the insect matrix 53 may pose food safety risks. DNA-based studies have already identified, among others, the 54 spore-forming genera Bacillus, Brevibacillus, Clostridium, Lysinibacillus and Paenibacillus in 55 edible insects and insect products produced in Europe 7-12 . Yet, it is generally not clear which 56 specific species were found and whether or not they were present in spore form. Consequently, 57 the first goal of this research (experiment 1) was to iden...

Unlocking the Potential of Insect-Based Proteins: Sustainable Solutions for Global Food Security and Nutrition

“…Vandeweyer and co-workers [186] assessed the microbial quality of mealworms and house crickets reared for human consumption, finding that proper processing significantly reduces microbial counts. Wynants and co-workers [174] demonstrated that blanching can effectively reduce microbial load in lesser mealworms, though some spores remain.…”

Tenebrio molitoras a source of interesting natural compounds, their recovery processes, biological effects, and safety aspects

“…As foodborne pathogens, Vandeweyer et al. (2020) evaluated the presence of foodborne viruses in edible insects and did not detect hepatitis A virus, hepatitis E virus, and genogroup II norovirus. Limited to these viruses, therefore, they can declare a low food risk.…”