Hygienic Characteristics and Detection of Antibiotic Resistance Genes in Crickets (Acheta domesticus) Breed for Flour Production

Abstract

During the last ten years, the worldwide interest in using insects as food and feed has surged. Edible insects fall within the category of novel foods, i.e., the category of food not consumed in significant amounts in the European Union before 15 May 1997 (the date of entry into force of Regulation (EC) No. 258/1997, later repealed by Regulation (EU) No. 2283/2015). One of the most promising insect species to be raised for food is the house cricket (Acheta domesticus). In this study, the rearing of a stock of house crickets was studied over a period of four months. The microbiological quality of the farm was studied using swabs on the surface of the rearing boxes to analyze the trend over time of different populations of microorganisms (total aerobic mesophilic microbiota, Lactobacillus spp., enterococci, Staphylococcus spp., Enterobacteriaceae, total coliforms, Pseudomonas spp. and molds). The presence of four antimicrobial resistance genes (aph, blaZ, sul1, and tetM) was investigated by polymerase chain reaction. A production scheme was also developed in order to obtain a cricket-based flour, which was analyzed for its microbiological and chemical-centesimal profile. The results obtained in this study demonstrate that the contamination increases with time and that a proper management of the farming system for insects is of the utmost importance, as it is for conventional farm animals such as ungulates, poultry, and rabbits. The old-fashioned adage “all full, all empty” for the farming system summarizes the need for proper cleaning and disinfection of the structures at the end of each production cycle.

Effects of Temperature and Density on House Cricket Survival and Growth and on the Prevalence of Acheta Domesticus Densovirus

“…With increasing rearing densities, the occurrence of cannibalism should also be monitored. In our density experiments, we did not record if cannibalism occurred, but insect rearing often has to deal with losses caused by cannibalism when the rearing densities are high [31,52,53], and crickets are known to be highly cannibalistic [54]. Cannibalism can also make the insects more vulnerable to opportunistic pathogens since the cuticle, the natural barrier preventing the entry of the pathogens, is penetrated.…”

Color, pH, microbiological, and sensory quality of crickets (Gryllus bimaculatus) flour preserved with ginger and garlic extracts

“…This was attributed to the heat treatment (drying at 105°C for 2 h), which was sufficient to destroy the fecal coliforms during the flour preparation, coupled with hygienic preparation processes. Live crickets are associated with a variety of pathogenic organisms, including fecal coliforms and E. coli (Grispoldi et al, 2021 ). Therefore, their absence from a food product is indicative of quality and safety (Woh et al, 2017 ).…”

“…The main issues reducing the shelf life of flour are microbiological growth, color change, and oxidative rancidity. Previous research suggests that crickets are contaminated with both harmful and spoilage micro‐organisms (Fröhling et al, 2020 ; Grispoldi et al, 2021 ). Furthermore, the sensory acceptability of a traditionally processed meat‐based product was marginally lowered after storage for 12 weeks (Mgbemere et al, 2011 ).…”

Viral and fungal pathogens in house cricket rearing : Effects of temperature, density and co-infection

“…With increasing rearing densities, the occurrence of cannibalism should also be monitored. In our density experiments, we did not record if cannibalism occurred, but insect rearing often has to deal with losses caused by cannibalism when the rearing densities are high [81,98,99], and crickets are known to be highly cannibalistic [100]. Cannibalism can also make the insects more vulnerable to opportunistic pathogens since the cuticle, the natural barrier preventing the entry of the pathogens, is penetrated.…”

“…At the highest rearing densities, the detrimental effect of the EPFs on cricket survival was stronger, indicating the importance to assess the possible stressors in combination. High rearing densities may also come with other challenges for cricket producers, such as increased risk of disease transmission and cannibalism, which is known to occur in house cricket rearing [100]. The occurrence of cannibalism in crickets can also in part explain the decreased survival at higher densities.…”