Developing Methods to Detect Microplastic Contamination in Livestock Feed: Implications for Sustainable Animal Husbandry

Microplastics, defined as plastic particles smaller than 5 mm, are increasingly detected in components of agroecosystems, including livestock feed. Their presence in animal feeding systems raises critical concerns related to food safety, animal health, and environmental impact. The aim of this study was to develop a method for the detection of microplastics in livestock feed as part of the IPA INTERREG Croatia–Serbia project “Pioneering ecosystem-based microplastics contamination reduction and climate change resilience in the cross-border region” (Eco(Re)Act).For this purpose, various combinations of procedures based on Fenton reactions and potassium hydroxide (KOH) digestion were evaluated. The final protocol, achieving extraction efficiencies of up to 85% for all tested microplastic types and feed matrices, consists of KOH digestion at moderate temperature (60 °C for 24 hours), followed by two to three cycles of Fenton oxidation. Microplastic detection was performed using the Bruker Lumos II system. The efficiency of the proposed method allows for the omission of additional density separation steps, significantly reducing processing time compared to existing protocols developed for other complex matrices (e.g., soil). Future methodological development will focus on the standardization of monitoring protocols and strategies for reducing microplastic exposure in livestock feed. This will help safeguard animal health and support environmental protection within the framework of integrated agroecological practices, while also contributing to a better understanding of the actual impact of microplastic contamination on livestock production.