Microbiological quality assessment of edible insects (Hermetia illucens) and their rearing substrates (Hermetia illucens) et de leurs substrats d'élevage

Abstract:

The microbiological safety of Hermetia illucens larvae, a promising insect for animal and human consumption, is at the heart of this three-year research project. However, the microbiological safety of this new food represents a public health concern. Very little microbiological data is available.  In this study, a systematic review of the literature was carried out, supplemented by experiments carried out on three farms to assess the influence of the use of different rearing substrates on the microbiological quality of larvae. The results show a high level of contamination of the larvae, potentially transmitted by the substrate. The study identifies the main pathogens, notably Bacillus cereus, Clostridium perfringens and Cronobacter spp. and underlines the importance of controlling substrate contamination and providing a microbial inactivation step during larval processing. These results contribute to the definition of control criteria and the optimization of production stages.

Background and challenges :
The growing demand for protein to meet the nutritional requirements of the world's expanding population poses a major challenge for the future. The use of insects as a source of protein is seen as a sustainable and effective alternative. The species Hermetia illucens (black soldier fly) is particularly promising, but its microbiological safety remains a major concern for its introduction.

Results:

The study revealed a high level of microbial contamination of Hermetia illucens larvae, potentially transmitted by the rearing substrate. Several pathogens were identified, including Bacillus cereus, Clostridium perfringens and Cronobacter spp. Results showed that larval contamination can vary according to the type of substrate used.

Outlook:

These results pave the way for safer insect protein production, guiding essential control criteria and identifying further research needs to optimize rearing and processing practices for Hermetia illucens larvae.

Valorisation:

The results of his study were presented in this publication and as an oral communication at the Microbes 2023 conference of the Société Française de Microbiologie (Rennes, October 4-6, 2023) and as a poster at the Microbes 2021 conference in Nantes. This work has advanced our knowledge of the microbiological safety of insect proteins, and is helping to promote the use of these proteins in animal and human nutrition.

Bibliographic references:

• Brulé, L.; Misery, B.; Baudouin, G.; Yan, X.; Guidou, C.; Trespeuch, C.; Foltyn, C.; Anthoine, V.; Moriceau, N.; Federighi, M.; et al. Evaluation of the Microbial Quality of Hermetia illucens Larvae for Animal Feed and Human Consumption: Study of Different Type of Rearing Substrates. Foods 2024, 13, 1587. https://doi.org/10.3390/foods13101587
• Brulé L., Djema R., Yan X., Moriceau N., Anthoine V., Baudouin G., GUIDOU C., Trespeuch C., Federighi M., Misery B. et Boué G. Évaluation de la qualité microbiologique des larves de mouches de Hermetia illucens pour l’alimentation humaine et animale : quel est l’impact du substrat ?, Oral communication presented at Microbes 2023, Rennes, France.
• Brulé L., Foltyn C., Anthoine V., Cariou V., Kooh P., Federighi M. et Boué G. Profil microbiologique de trois espèces d’insectes comestibles : Tenebrio molitor (TM), Acheta domesticus (AD) et Hermetia illucens (HI), Poster presented at Microbes 2021, Nantes, France.