Aflatoxin B1 accumulation in Tenebrio molitor: a preliminary assessment

With the population growth rate, there are some concerns that food production will not be able to keep up with this growth. Edible insects seem to present a sustainable solution. Farming these insects presents an opportunity to drain the production of the by-products by reusing them as bio-feedstocks and reintroducing these components into the food value chain. However, these products can present several contaminations, including mycotoxins, which can be accumulated in insects after exposure to the contaminant, and be detected at the end of the food chain. The ENTOSAFE project aims to address these concerns and evaluate the potential risk for the consumer. The principal aim of this study was to evaluate the mycotoxin aflatoxin B1 (AFB1) accumulation in Tenebrio molitor (yellow Mealworm, YMW) exposed to a spiked AFB1 feed subtract at maximum levels in cereals and products derived from cereals (2 µg/kg) and ten times higher (20 µg/kg). AFB1 contents were quantified in both feed substrate and T. molitor samples, before and after a 14-days of exposure and mycotoxins (aflatoxins and ochratoxin A, OTA), detected by HPLC-FD detection. Results concerning non-contaminated feed substrate revealed absence of AFB1 and presence of OTA, the latter (0,8 µg/kg) presenting values below the legislated value of 3 µg/kg, for cereals and products derived from cereals (European Commission, 2023). AFB1 spiked feed substrates revealed values slightly higher (4 and 23 µg/kg) than the theoretical contamination levels of 2 and 20 µg/kg. OTA values remain close to the previously reported. No changes occurred in contamination levels at beginning and 14-days AFB1 exposure assays. Results concerning T. molitor larvae, revealed absence of OTA along exposure assays and different AFB1 contamination levels. AFB1 contents in low (0.011 µg/kg) and high (0.022 µg/kg) AFB1 contamination levels were close, and below the 2 µg/kg legislated level for cereals and products derived from cereals (European Commission, 2023), after the 14-days exposure. The reported results are preliminary, so several aspects need to be improved as mycotoxin analytical method validation, mycotoxin contamination procedure and a higher number of samples to get representative results on AFB1 accumulation in insect larvae.This study was supported by the project ENTOSAFE (PTDC/CTA-AMB/0730/2021), financially supported by national funds (OE), through FCT/MCTES, as well as for financial support to CESAM by FCT/MCTES (UIDP/50017/2020 + UIDB/50017/2020 + LA/P/0094/2020), through national funds. D. Cardoso was hired under the Scientific Employment Stimulus – Individual Call (CEECIND/01190/2018).