Microplastics in Commercial Milk for Human Consumption: Evidence From a Systematic Review and Meta-Analysis

The global increase in plastics production and consumption has heightened human exposure to microplastics (MPs), raising widespread concern. Food represents a major route of human exposure. Since milk is a vital component of the human diet throughout life, its contamination warrants close attention. The current study is the first meta-analysis focusing on MP contamination in commercial milk. Three databases (PubMed, Embase, Scholar, and Web of Science) were searched up to June 2023, following the PRISMA guideline. Four relevant studies were included based on specific inclusion and exclusion criteria. The risk of bias (RoB) was assessed using the Office of Health Assessment and Translation (NTP/OHAT) tool. Four low-RoB studies were included in the meta-analysis. The results indicated that MP concentrations in the analyzed studies ranged from 16 to 10040 particles per sample. Given that milk contamination can occur at all stages (from farm to consumer), future studies should investigate how processing and packaging contribute to the presence and diversity of MPs in milk and their potential health effects. Additionally, standardized sampling and detection protocols should be developed to accurately detect and minimize MP contamination in milk. Preventive strategies are needed to limit the release of MPs into the environment and, consequently, the human body.