Microbiological and nutritional aspects of black soldier fly (hermetia illucens) larvae after bioconversion of different food wastes

Anotace: Black soldier fly larvae (BSFL), Hermetia illucens, have shown remarkable potential for food waste bioconversion, contributing to sustainability and waste management efforts. This study evaluated the effects of different food waste compositions (three types of diets: egg pasta in milk, rice with peas, and couscous mixture with egg, spinach, and carrot peels) and their microbial quality (fresh vs. spoiled) on BSFL bioconversion efficiency, microbiology, and nutritional value. Microbiological analyzes of the larvae were performed using the plate dilution method and MALDI-TOF mass spectrometer. All test variants spotted successful bioconversion. However, bioconversion efficiency (BE) and waste reduction rate (WR) were highest for couscous-based diets, with fresh couscous yielding a highest BE of 27.41% and WR of 81.34%. Nutritionally, larvae reared on mixture of couscous, egg, spinach, and carrot peels displayed the highest protein content (up to 35.5%). Microbial analysis indicated increased microbial counts, particularly Enterobacteriaceae and spore-forming bacteria, in larvae fed spoiled diets. Potentially pathogenic microorganisms such as Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Morganella morganii were detected, underscoring the need for microbial safety measures in BSFL-based applications. This study highlights the critical role of feed composition and quality in determining the efficiency and safety of BSFL bioconversion, providing valuable insights for optimizing their use in sustainable food waste management and as a resource in feed or food production.