Black soldier fly larvae (Hermetia illucens) (BSFL) are a promising protein source for the feed industry. They can be used to convert organic waste into valuable biomass, and due to their chemical composition, they are a valuable ingredient for several industrial sectors. To use BSFL as a feed ingredient, their chemical safety must be guaranteed. The composition of their rearing substrate is one of the crucial factors for safety, since it might introduce safety risks by bioaccumulation of various (in)organic compounds (e.g. toxic metals, mycotoxins, pesticides, etc.) in BSFL. Though several organic waste streams are potential and valuable rearing substrates for BSFL, the European Union currently does not allow their use due to safety knowledge gaps. This has prompted researchers to conduct several exposure experiments by artificially spiking chemicals to the rearing substrate of BSFL to investigate such risks. Here, we present a critical overview of the current body of literature on this topic and discuss the main findings, gaps, and recommendations for future research. Overall, BSFL do not seem to accumulate contaminants above the European feed legislation limits, except for certain metals (i.e. cadmium, lead, and zinc), which can jeopardise the chemical safety of the BSFL. For all compounds explored to date, except for cyromazine and pyriproxyfen, their presence in the substrate has no effect on the larval growth or survival rate. However, the remaining knowledge gaps concerning other potential hazardous chemicals (e.g. plasticisers, flame retardants, etc.) and their degradation pathways in BSFL still warrant an appropriate chemical safety assessment and can be a reason why several organic waste streams are not yet allowed to grow BSFL. The risks induced by the potential presence and accumulation of other chemical compounds requires further research to enable the safe exploitation of BSFL.

Due to the expansion in the global population, there is an increase in animal protein demand and waste generation. Currently, food waste derived from supermarkets, etc., which is used to produce biogas, is collected separately and can contain (micro)plastics deriving from food packaging, imposing potential risks to the environment. A possible solution to address protein, waste and plastic concerns can potentially be achieved by rearing black soldier fly (BSF) larvae on such substrates. In this study, we investigated the effect of polyvinyl chloride (PVC) (micro)plastics on the growth, survival, and bioconversion of BSF larvae. On the other hand, the impact of the larvae on the polymer structure and degradation was also assessed. This was carried out by rearing BSF larvae on artificial food waste spiked with micro-, meso-, and macroplastics, while measuring larval growth, survival, and bioconversion parameters. The remaining plastics were collected and analysed upon changes and degradation of their polymer structure. Generally, BSF larvae were not affected in terms of growth performance (179.9–210.4 mg), survival (77.1–87.3%), and bioconversion (FCR: 4.65–5.53) by the presence of (micro)plastics in the substrates. Furthermore, the larvae were also unable to significantly alter the polymer structure of the used plastic.