Tenebrio molitor, the first edible insect approved as a novel food in the EU, is a promising candidate for alternative protein sources, implementing circular and sustainable production systems. This study aims to determine the microbiological quality and physicochemical properties of mealworm powders obtained by four different processing pathways. Contents of dry matter, protein, fat, ash, water activity (aw) and a range of microbial counts were measured and analyzed by one-way ANOVA with Tukey’s test. Results showed small differences in the proximate composition of the powder samples (protein 55.62–57.90% and fat 23.63–28.21% of dry matter, DM), except for the one that underwent a defatting step (protein 70.04% and fat 16.84%), p < 0.05. A level of water activity of less than 0.2 was reached for all pathways. Fresh mealworm samples had high total aerobic counts (8.4 log CFU/g) but were free of foodborne pathogens. Heat treatments applied during transformation were sufficient to kill vegetative cells (reduction of 2.8–5.1 log CFU/g) rather than bacterial endospores (reduction of 0.3–1.8 log CFU/g). Results were confirmed by predictive microbiology. This study validated the efficacy of a boiling step as critical control points (CCPs) of insect powder processing, providing primary data for the implementation of HACCP plans.

In the context of climate change and depletion of natural resources, meeting the growing demand for animal feed and human food through sufficient, nutritious, safe, and affordable sources of protein is becoming a priority. The use of Hermetia illucens, the black soldier fly (BSF), has emerged as a strategy to enhance the circularity of the agri-food chain, but its microbiological safety remains a concern. The aim of the present study was to systematically review available data on the microbiological quality of BSF and to investigate the impact of using four different rearing substrates including classic options allowed by the EU regulation (cereals, fruits, vegetables) and options not allowed by EU regulations regarding vegetable agri-food (co-products, food at shelf life, and meat). A total of 13 studies were collected and synthesized, including 910 sample results, while 102 new sample results were collected from the present experiments in three farms. Both datasets combined revealed a high level of contamination of larvae, potentially transmitted through the substrate. The main pathogenic bacteria identified were Bacillus cereus, Clostridium perfringens, Cronobacter spp., Escherichia coli, Salmonella spp., and Staphylococcus aureus coagulase-positive, while Campylobacter spp. and Listeria monocytogenes were not detected. Any of these four substrates were excluded for their use in insect rearing; however, safety concerns were confirmed and must be managed by the operators of the sector using microbial inactivation treatment after the harvest of the larvae in order to propose safe products for the market. The results obtained will guide the definition of the control criteria and optimize the following manufacturing steps.

In Europe, people are increasingly interested in edible insects to meet the growing demand for food diversity and protein supply, and bring expected nutritional and environmental benefits. Among all insect-based foods, insect powder is one of the most promising choices, which presents added advantages in the ability of mixing with versatile ingredients, long shelf-life and higher consumer acceptance (non-recognisable form). As a novel protein source, insects require the well-designed manufacturing process to produce high quality insect powder, while guaranteeing food safety of the final product. This review provides a brief overview of the current consumption patterns and general processing steps of insect powders. With regard to inactivating potential microbial hazards, traditional thermal treatment (e.g. boiling, blanching,) is still the predominant method in insect sector, which shows a desirable microbial reduction but may affects nutritional properties and organoleptic attributes. The use of food preservatives and fermentation have also been incorporated as means for eliminating pathogenic bacteria in some insect products. Recent years, a set of advanced or innovative technologies have been developed for inactivation of microorganisms in various foods while maintaining food quality, such as infrared heating, instant control pressure drop technology, high hydrostatic pressure, and cold plasma. However, except for the initial exploration of very few techniques in the laboratory, most novel technologies have not been attached much importance in insect sector. Eventually, this review highlights the lack of data on the impacts of different processing methods (both conventional and innovative, individual or in combination) for edible insects, encompassing the control of microbial activities, nutritional value, and sensory qualities.

Consumption of edible insects as an alternative protein source has recently gained attention for its potential beneficial impacts on the environment, nutrition, and food security compared to traditional sources. However, despite being a traditional food in some parts of the world, its acceptance is still limited, especially in Europe. The present study aims to examine consumers’ willingness to eat (WTE) different insect-based foods (IBF) and investigate determining factors for acceptance in countries with or without entomophagy traditions. An online cross-cultural survey was conducted in France (n = 515) and China (n = 594) in April 2023. Several explanatory variables were established, and their effects on the acceptance of insect foods was analysed by applying multiple linear regression. The results showed that Chinese respondents had higher willingness to eat insects than French respondents, with a different preference ranking of thirteen IBFs. In both countries, significant predictors of consumers’ willingness to eat insects were the low insect visibility, low food neophobia and disgust level, previous experience of consuming insects and knowledge of insects’ nutritional and environmental benefits. Consequently, the inclusion of insects in the daily diet of French and Chinese consumers requires a transitional phase to familiarize consumers with processed foods containing invisible insects and establish positive perceptions of insect foods.

The increasing demand for sustainable protein sources highlights Hermetia illucens (Black Soldier Fly, BSF) as a promising alternative. However, microbiological safety remains a key concern. This study investigated the microbial diversity of BSF larvae, comparing two processing methods: (1) boiling followed by drying and (2) drying alone. Microbial diversity was assessed via 16S rRNA sequencing, while bacterial loads were quantified using culture-based methods on samples from a French company. A systematic review complemented this analysis by synthesizing the existing knowledge on BSF microbiota. The rearing conditions varied, with substrate pH ranging from 4.1 to 9.0 and ambient temperatures between 24.6 °C and 42.7 °C. Mesophilic bacteria, spores, and lactic acid bacteria reached up to 8.6, 7.7, and 8.5 log CFU/g in the substrates and larvae, while yeasts, molds, and sulfite-reducing bacteria remained below 4.8 log CFU/g. Boiling reduced most loads below detection thresholds, particularly for yeasts, molds, and ASR. Salmonella, Listeria monocytogenes, Cronobacter sp., and coagulase-positive staphylococci were absent, whereas Clostridium perfringens and Escherichia coli were variably detected. Metabarcoding showed shifts in composition, with Proteobacteria, Bacteroidota, Actinobacteriota, and Firmicutes (Bacillota and Clostridiota) dominating. Process 1 more effectively reduced the bacterial loads, though Bacillus and Clostridium remained. Campylobacter sp. detection in powders raises food safety concerns.