La contamination des produits alimentaires par les microplastiques

Microplastics are present in all environment compartments: air, water and soil, and have even been detected in human body, with food consumption being one of the routes of exposure. However, there is still a few studies and not all food matrices are targeted.The main objective of this thesis work is to develop research on the contamination of various foods by microplastics, in order to supplement current data. In order to meet this objective, the assessment of contamination in various beverages and meat products was a central focus of this thesis. The study on beverages focused on bottled water, non-alcoholic soft drinks (cola, iced tea, and lemonade), and alcoholic beverages (beer and wine) contained in various food packaging materials (plastic, glass, carton, box, can). The results showed contamination in all beverages and packaging, with higher levels of microplastic contamination in glass bottles. The external paint on the capsules was suspected to be the main source of contamination, as the majority of the isolated particles were identical to the color of this paint and shared the same chemical composition. The study on meat products focused on various meats (steak, ground beef, pork stir-fry, roast pork, chicken breast) from supermarket shelves and a supermarket butcher shop. Heterogeneous contamination results were observed, with meat from supermarket butchers proving to be more contaminated. The black and red polyester and cotton fibers found in these samples suggest that the contamination may have come from personal protective equipment for employees. At the same time, a unified methodology for analyzing microplastics in certain food categories (dairy products, fruits, vegetables, legumes, cereals and cereal products, sweet products) has also been developed and implemented, with the aim of harmonizing protocols and ensuring the comparability of results. Various digestion reagents such as KOH, H2O2, HNO3, and HClO4 were applied to these matrices. The impact of the protocols on the integrity of a set of polymers (nylon, polyethylene, polyester, polyvinyl chloride, and polystyrene) was then evaluated using positive controls.