Black soldier fly larvae and T. reesei treatment – exploring the fate of the mycotoxin patulin

Sammanfattning

In order to transition our food system from a linear to a circular one we need more tools to recycle, not only plant nutrients, but proteins and fats from all types of waste streams. Black Solider Fly Larvae (BSFL) composting offers a good solution both as waste management strategy and for replacing other unsustainable protein sources. Mycotoxins are secondary metabolites produced by several molds (fungi) that can cause serious harm to humans and animals. In order to safely rear BSFL on food waste or other type of waste streams it is important that associated risks are investigated. This study was conducted in two parts: a Literature review and an experimental trial. This study begins with literature review to identify the types of mycotoxins previously investigated in the context of BSFL. The experimental trial evaluated three methods for inactivating the mycotoxins patulin. One treatment with T. reesei, one with BSFL composting and one combined treatment. The literature review revealed that either no or only low concentrations of studied mycotoxins have been detected in the larvae. The low concentrations observed in the larvae have been linked to very high concentrations in the input material; yet the concentrations in the larvae have been below EU regulatory limits. The result of the experimental trial showed that larval weight gain where not affected by patulin. Combined treatments showed the highest larval survival and the highest loss of volatile solids (VS). In terms of patulin inactivation, samples were sent to two different commercial laboratories, while a control sample was sent to a third for verification. The results obtained where not reliable enough to draw any conclusions. The key take-away message from the patulin analysis were that the methodology must be further developed to obtain trustworthy results. Trustworthy mycotoxin analyses is a crucial part of getting a safe and circular food system in the future.