Circular Economyin Swiss Food Sidestreams: A CO₂ Footprint Analysis

In this study, we surveyed and analyzed 27 Swiss food companies to assess their generation and valorization of six specific sidestreams: whey, soy whey and okara, potato peelings, bovine blood, poultry feathers, and rapeseed and sunflower cake. These residual materials are consistently produced in large quantities during food processing. Our data reveal that most sidestreams are currently used for biogas and animal feed, with human nutrition primarily limited to whey from cheese production. We assessed the CO₂ footprint of four valorization scenarios using data from existing literature, e.g., landfilling, animal feed, bioplastics, and biogas production within the food waste hierarchy. Landfilling and bioplastics had the highest emissions, at 252 and 228 kg CO₂ per ton of sidestream, while animal feed and biogas had the lowest at 87 and 13 kg CO₂. However, bioplastics provide environmental benefits by replacing conventional plastics and reducing reliance on fossil fuels, offering additional CO₂ savings. Discussions with companies revealed growing interest in sidestream valorization but also highlighted challenges such as perishability and production structures, underscoring the need for improved management, valorization pathways, and economic considerations. Overall, this work paves the way for more circular practices in the food industry, reducing waste and fostering eco-friendly innovations.