Chemical safety of black soldier fly larvae (Hermetia illucens), knowledge gaps and recommendations for future research: a critical review

Abstract

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.

Preliminary Data on Essential and Non-Essential Elements Occurrence in Processed Animal Proteins from Insects

“…Instead, larvae fed with plant or broilerbased substrate showed higher content of Cr, Cu and Se [23,43]. Low concentration of Ni and Zn were found both in substrate and in larvae [43], and concentrations of As, Cd and Pb were found comparable to literature data [23,[43][44][45][46].…”

“…Since larvae could be farmed on different substrates, it has been demonstrated that in speci c conditions or growth stages, H. illucens could bioaccumulate Cr, Cu, Fe, Se, Sn, Zn, Cd and Pb while no accumulation happens for Al and As [23,43]. The similarity of cadmium to calcium makes it easily bioavailable in larvae, where it can cumulate in the exoskeleton, as it happens for chromium [44]. Non-essential elements could be found in different concentrations in feed according to its origin, for example seaweed is a source of As which is well known as contaminant [46].…”

Valorisation Potential of Using Organic Side Streams as Feed for Tenebrio molitor, Acheta domesticus and Locusta migratoria

“…Although not discussed in this review, food safety must be considered when using insects for certain applications (e.g., food and feed), especially when they are produced on side streams. The insects’ feed might introduce safety risks by microbial contamination and accumulation of several compounds in the insects, such as toxic metals, mycotoxins and pesticides [ 132 , 133 ], etc. Although research has been conducted regarding this topic, knowledge gaps are still present, which is mainly the reason why the European Union currently does not allow the use of several side streams as insects substrate.…”

Occurrence of Clostridium perfringens vegetative cells and spores throughout an industrial production process of black soldier fly larvae (Hermetia illucens)

“…As the demand for animal feed sources rises, insects are increasingly considered as a sustainable protein rich feed source (Stamer, 2015;Vandeweyer et al, 2021;Wang and Shelomi, 2017). Black soldier fly larvae (Hermetia illucens L., Diptera: Stratiomyidae) are known for their interesting nutritional value for animals, growth potential on various organic waste streams, high bioconversion ratio and low environmental impact (Diener et al, 2009;Joosten et al, 2020;Lievens et al, 2021;Makkar et al, 2014;Oonincx et al, 2015). While in Europe, Regulation (EC) No 2017/893 (EC, 2017) allows the use of black soldier fly larvae (BSFL) in aquafeed, the use of processed larvae in ruminants and monogastric animals is still prohibited at this moment by the EU feed ban or Regulation (EC) No 999/2001 (EC, 2001).…”