Sustainability is the buzzword of the decade. In an effort to reduce the staggering statistic that 40% of food produced globally goes uneaten, the food industry is pivoting toward a “Circular Economy” (CE). The goal is noble: minimize waste by keeping resources in use for as long as possible. This has given rise to “upcycled” foods—turning waste streams (like spent grain from brewing or vegetable peels) into novel foods and animal feeds. But as we rush to close the loop, are we inadvertently introducing new risks to our diet?
When Waste Becomes Food: The circular economy encourages using by-products and “former food products” (FFPs) as ingredients for new foods or livestock feed. While this reduces landfill use, it challenges the traditional definition of food safety. The core issue is that waste streams were not originally designed to be food ingredients.
For example, using recycled paper packaging in a circular model can lead to contamination. Residues from inks or printing materials in recycled paper can migrate into food, introducing mineral oil hydrocarbons (MOSH/MOAH) into the diet. Similarly, reusing wastewater for urban agriculture—a key pillar of sustainable farming—risks introducing antibiotic-resistant genes and pathogens into fresh produce if the water is not treated with expensive, advanced filtration technologies.
The Buzz About Insects: Perhaps the most discussed aspect of the circular economy is the use of insects, such as yellow mealworms and black soldier flies, as a sustainable protein source. Insects are masters of “upcycling,” capable of turning low-grade organic waste into high-quality protein. However, the safety of the insect is entirely dependent on what it eats.
Research shows that risks to human and animal health from insects are strongly correlated to their rearing substrate (the waste they are fed). Insects can bioaccumulate contaminants. For instance, studies have shown that insect larvae can accumulate heavy metals like cadmium and nickel from their diet,. If insects are fed waste containing these metals, and we then eat the insects (or animals fed on them), we ingest those concentrated toxins.
Furthermore, biological hazards persist. Insects reared on certain waste streams have been found to carry antibiotic-resistant genes in their gut and “frass” (waste), which poses a risk of spreading resistance into the environment. There is also the issue of allergens; insects reared on substrates containing gluten can retain that gluten, posing a risk to those with celiac disease unless the insects are specifically “fasted” and washed before processing.
The Safety Gap: The enthusiasm for upcycled food often outpaces the safety data. While safety standards in the EU are high, effectively minimizing physical hazards like plastic packaging in former food products, there are still significant data gaps regarding chemical and microbiological risks.
Processing technologies like freeze-drying and sterilization can mitigate some bacterial risks in novel foods, but they are energy-intensive, which ironically can increase the Global Warming Potential (GWP) of these “sustainable” foods compared to conventional options.
The transition to a circular economy is essential for the planet, but it requires a “safe-by-design” approach. We must ensure that in our rush to save the planet, we do not turn our food supply into a repository for concentrated contaminants.
