Insect detection in foods through an SSR-based approach

Insects are a valuable source of essential peptides and amino acids that are beneficial to human health. They represent also an efficient alternative to animal and vegetable proteins also in terms of space and water. In 2019, the EU approved four insect species as novel foods safe for human consumption on the European market: Tenebrio molitor larva (yellow mealworm), Locusta migratoria (migratory locust) Acheta domesticus (domestic cricket) and Alphitobius diaperinus. This has opened the way to new protein sources alternative to meat but also hides a potential risk of fraud. Currently, there are no analytical approaches available to track the presence and quantities of insects authorized for food production. This work aims to identify analytical approaches that are useful both for the identification of insect species present in foods and for possible fraudulent activities during the production process. In particular, we used a molecular approach based on molecular SSR markers, as they are easy to use, inexpensive and capable of analysing highly degraded DNA. This approach was used for the detection of the four authorised insect species. To evaluate the accuracy of the proposed approach, we also analysed 4 homemade mixtures with increasing amounts of an insect-specific contaminant, which allowed the estimation of the detection limit of 5% (w/w). Finally, we demonstrated the feasibility of the proposed method and its effectiveness in detecting undeclared insects when they are present at a percentage of 5% or more.