In this collaborative study between the International Institute of Tropical Agriculture (IITA) Benin and Kretsloppsteknik, published in the Journal of Insects as Food and Feed, we investigated the risks of rearing black soldier fly larvae (BSFL) on biowaste streams available in Benin.
We found that most biowaste streams were contaminated with copper, chromium, cadmium, lead, and zinc, but the concentrations were below the standard limit values for animal feed. Fresh BSFL reared on these biowastes were contaminated with salmonella, which contrasts with our previous research findings, where the BSFL process typically results in a large reduction in salmonella. We believe this difference was due to the high moisture content of the substrates, which made the BSFL process less efficient. Interestingly, no salmonella was detected in larvae reared on tigernut, a substrate with more optimal moisture content, which also led to a more efficient BSFL conversion process. After blanching, salmonella levels in all larvae samples were below the detection limit.
We also found that cabbage waste contained high levels of the insecticide emamectin, but the levels in the larval biomass and the frass were below the detection limit.
This study highlights the importance of tailored management strategies for specific waste streams in circular waste management for feed production to ensure that the resulting products are safe from chemical and biological contaminants. While risks exist, they can often be managed to ensure safety, unlocking the full potential of biowaste streams and driving a sustainable circular future.
We are happy to share our new publication “Advances in substrate source composition for rearing black soldier fly larvae as a protein source“, published as a chapter of the book “Insects as alternative sources of protein for food and feed”, published by Burleigh Dodds Science Publishing
In this chapter, Cecilia and Ivã discuss some of the challenges faced by the BSF industry in relation to the feed substrates available for rearing this amazing insect species. Bioconvesion is affected by many variables and it is not easy to always have good predictability of the process and product composition combined with environmental sustainability.
We strongly believe that the real value of BSF larvae can only be extracted when waste streams are used as feed substrate (especially post-consumer waste) and when the larvae end up as feed for livestock. This, in our view, is the real path to sustainability!