Multi-mycotoxin method applicable for the safety assessment of waste-fed black soldier fly (Hermetia illuscens) larvae on the way to circular bioeconomics

The ability of Black Soldier Fly (H. illuscens, BSFL) larvae to feed on substrates containing mycotoxins can make them key components for waste revalorisation in circular bioeconomic approaches. However, safety aspects concerning derived larval products are currently hindering the full exploitation of their potential since the established maximum levels for mycotoxins in feed also apply to insects. A regulation change would require experimental data confirming that BSFL do not accumulate mycotoxins after dietary exposure at levels that can be present in waste materials. A prerequisite is the availability of reliable analytical methods suitable for mycotoxin quantification in BSFL matrix. For this purpose, we have developed and validated a multi-mycotoxin ultra-performance liquid chromatography high-resolution mass spectrometry (UPLC-HRMS) analysis including an effective extraction procedure. The new method was applied to determine deoxynivalenol (DON) in larvae, feed and frass from a BSFL exposure study using 29 mg DON/kg. Notably, larval growth remained unaffected at this substantial mycotoxin level. Only low DON concentrations were measured in the BSFL at study end, whereas their frass was highly contaminated. We concluded that the larvae did not contain the mycotoxin after uptake and would be valuable assets for bioeconomic purposes. In contrast, subsequent use of the frass appeared to be contraindicated.