From Waste to Resource: Performance of Black Soldier Fly Larvae Reared on Restaurant Food Waste at an Industrial Scale

Food waste poses significant environmental, economic and public health challenges. The black soldier fly (Hermetia illucens) larvae (BSFL) represent a promising solution for organic waste valorisation, converting substrates into protein-rich biomass for animal feed and organic fertiliser. However, the use of food waste as an insect substrate remains prohibited in the European Union due to regulatory and safety concerns. This study evaluated the suitability of heterogeneous food waste for BSFL rearing under industrial conditions by comparing larval performance on a standard Gainesville diet (control) and a blend derived from local restaurant waste (test). The 14-day bioconversion assay assessed bioconversion rate (BCR), feed conversion ratio (FCR), survival rate, average growth rate, and nutritional composition. Compared with the control, the test group showed significantly improved (p < 0.001) BCR (18.34% vs. 11.02%), FCR (5.48 vs. 9.09 kg/kg), survival (69.29% vs. 51.30%), and growth (8.38 vs. 6.59 mg/day). Larvae reared on food waste also exhibited significantly higher protein (19.70% vs. 16.80%), fat (13.70% vs. 7.20%), ash (6.97% vs. 3.51%), carbohydrates (7.00% vs. 3.60%), and fibre (5.20% vs. 2.90%). Overall, heterogeneous food waste is a suitable substrate for BSFL, supporting agrifood sustainability; however, future research should focus on standardisation of these substrates.