Circular economy in feed production by fly larvae composting - risks of accumulation of persistent disease agents in the reuse chain

The aim of this project is to assess the risks with a circular economy waste management system in which animal feed is produced from food waste with fly larvae, and to investigate the barriers required for keeping the risks at acceptable levels.

In this project, the fate of prions and anaerobic bacteria (vegetative and spore) in fly larvae composting will be assessed.

In addition, in depth studies on the mechanism responsible for the documented reduction in Salmonella spp. in fly larvae composting will be undertaken.

In order to assess whether the reduction is due to passage through the larvae digestion tract or due to the excretion of antimicrobial substances into the substrate, the larvae will be allowed to consume highly contaminated material (aerobic and anaerobic bacteria) and the concentration of studied bacteria analysed in their excreta.

In another experiment, the treatment residue (frass) will be re-contaminated with pathogenic bacteria upon finalised fly larvae composting and the concentration of selected bacteria monitored over time in frass stored for different amounts of time. In the final part, a risk assessment will be conducted using the data gathered in the project.

The risk for accumulation of prions and spores of anaerobic bacteria in fish and poultry fed food waste reared fly larvae for 50-years of implementation of this circular waste management system, and possible  mechanisms required to keeping the risks at acceptable levels, will be modelled.