In a review article recently published in the scientific journal Waste Management, ATB scientists outline the possibility of using insects to efficiently and sustainably recycle food waste. This insect-based bioconversion can help to close material cycles in the food value chain.
Food loss and waste threaten the sustainability of our food systems. According to the Food and Agriculture Organisation (FAO), global food losses amount to about 1.3 billion tonnes per year. Losses occur along the entire value chain - from production through trade to the final consumer. In the EU, more than 50% of total food losses occur at consumer level - per capita between 95 and 115 kg/year.
Food that is no longer suitable for human nutrition is currently used - at best - as animal feed, for energy production in biogas plants or for composting.
A promising new way to bring food waste to a sustainable use is the production of insects using food waste as feed. Insects have much more efficient feed conversion rates compared to traditional animal production systems, they require significantly fewer resources such as land, water and feed, and they cause less environmental impact. For example, the production of 1 kg of crickets causes only about 0.3% of greenhouse gas emissions compared to poultry. The animals themselves are suitable both for human and animal nutrition due to their high-quality components, but they can also be used for the production of non-food products such as biofuel, pharmaceuticals or dyes.
Their fast growth enables insects to efficiently recycle large quantities of food waste in a short time. "The success of waste-based insect production depends on the insect species, the rearing conditions and especially on the composition and consistency of the insect food. If the feed composition varies, as is typical for biowaste, this can have a major impact on the growth rates of the animals, their time to maturity and on subsequent processing, which turns robust process control into a challenge," summarises ATB scientist Dr. Shikha Ojha.
Research is needed in particular in the process design for the production of insects and in post-harvest food safety. For example, physical and biological treatments of biowaste used as insect feed, such as homogenisation and fermentation, can improve the digestibility and bioavailability of nutrients for the insects. Post-harvest processing methods such as blanching and drying, but also novel approaches such as the use of plasma, high voltage pulse and ultrasound technology are currently in the focus of research. Studies at ATB have shown, for example, that treating mealworms with plasma application reduced the microbial load while improving the techno-functional properties of the product. The use of novel pretreatments in combination with advanced extraction technologies can improve the recovery of key macromolecules from insect matrices.
Furthermore, there is a need for research to assess the environmental impacts of insect use for food and feed production systems, the authors point out. The ATB scientists have compared the studies on Life Cycle Assessment published to date. Recent studies conclude that the production of insect biomass is twice as sustainable as chicken meat. Even though there is evidence of a lower environmental impact, the ATB experts argue that the recycling of waste streams should be explicitly given greater consideration in the assessment. They concluded that a climate-friendly use of biowaste by insects to generate high-quality products was ideally in line with the concept of a circular economy and could contribute to shaping our food system in a more sustainable way.
Last but not least, the industrial production of insects also generates waste: organic waste from unused feed, discarded skins (exuviae) and excrements can be spread on agricultural fields as fertiliser - in line with the principles of a circular economy.