Optimizing food safety and nutritional quality in edible insects: diet–fasting interactions shape microbiological safety and elemental composition of Tenebrio molitor larvae

Abstract

The growth of edible insects as a sustainable protein source requires robust strategies to ensure their safety and nutritional quality. However, the combined eOects of diet composition and fasting on the microbiological safety, elemental composition, and nutritional quality of Tenebrio molitor larvae remain insuOiciently characterized. This study systematically evaluated the eOects of vegetable-based diets and fasting periods on fresh T. molitor larvae by assessing microbial enumeration with potential pathogen identification using MALDI-TOF MS and elemental profiling by ICP-OES. Diet significantly influenced the microbiological profile of 4-week-old larvae, representing an active growth stage, whereas eOects related to diOerent batches were more pronounced at 6 weeks, when fasting was applied, indicating stage-dependent variability. In contrast, elemental composition was consistently aOected by diet and fasting duration, with no significant batch influence. Larvae reared on mixed vegetable or carrot-based diets with 24 h fasting exhibited the best balance between reduced microbial load and stable elemental composition. These findings demonstrate that both diet composition and fasting duration influence the microbiological safety and nutritionally relevant elemental composition of T. molitor larvae under controlled rearing conditions. This study improves the understanding of how rearing and handling practices aOect edible insect quality and provides evidence to support the optimization of sustainable insect production systems.