Stored-product moths as potential pests of insect-based products

Acheta domesticus (Orthoptera: Gryllidae) is one of the species included in the "novel food" list of the European Union, which has authorized the use of insects as an alternative protein source for food and feed (EU 2035/5 - 3/01/2023). The use of this species, both whole and in powder form, has been authorized as an ingredient in the preparation of foods such as bread, crackers, biscuits, and protein bars. European consumers appear to be more likely to consume products containing processed insects than whole insects. Like other products, foods containing insects may be subject to infestation by stored product pests. The following Lepidoptera species Plodia interpunctella, Corcyra cephalonica, and Ephestia kuehniella (Lepidoptera: Pyralidae) were considered, and their ability to complete development on cricket powder and on biscuits containing different percentages of cricket powder was evaluated. In addition, the fertility of moth females emerged from the tested substrates was examined. For this purpose, cricket powder and three types of biscuits formulated with different inclusion percentages of cricket powder and/or hazelnut were infested with 100 eggs of each lepidopteran species. Five replicates for each species and treatment were set up, and these were checked three times a week until the emergence of adults. A standard diet was used as a control for the cricket powder trials and a biscuit prepared with only wheat flour for the biscuit trials. The new emerged adults were then counted, sexed and, to assess fertility, couples were created. Among the species tested, only E. kuehniella did not grow on cricket powder or any type of biscuit, while the other species developed on cricket powder until adult emergence, with different survival rates and development times. When considering the fertility of females emerging from standard diets and cricket powder, the average number of new larvae was significantly higher on the standard diet for C. cephalonica and P. interpunctella. Regarding the biscuits, damage such as silk, exuviae, or larval excrement was always observed, but only few individuals were able to complete development. The highest survival rates were observed for P. interpunctella on biscuits containing 10% of cricket powder (1.6%), while in all other cases, the emergence rate was below 1%. The results showed that these moths are able to infest both cricket powder as such or used as an ingredient. Pest management is essential in this context, especially as a significant increase in insect-based products is expected in the coming years. Further research is therefore needed to determine the susceptibility of these products to attack also by other stored product pests. Research funded under the European Union project "ON Foods - Research and Innovation Network on Food and Nutrition Sustainability, Safety, and Security - Working ON Foods"(NRRP, No. 1550)