Exposure to microplastics from food: Comparative analysis of food types and quantification techniques

Microplastics (MPs) are a widespread environmental pollutant and their presence in food is reported. However, abundance and characteristics of MPs, such as polymeric identity and size distributions, have not yet been comprehensively scrutinized in the dietary context. In this work, we collected a dataset of MP concentrations in food extracted from 193 papers (number-based concentrations) and 12 papers (mass-based concentrations). We reviewed present data on MPs with respect to 13 food and drink categories (meat, grains, fruit and vegetables, fish, crustaceans, mollusks, tap water, bottled water, beer, milk, sugar and honey, salt, other beverages). We found that the number of papers does not reflect dietary habits, with papers on seafood being overrepresented. This is presumably due to filter-feeding marine animals being expected to accumulate higher MP numbers. Although most works so far have focused on seafood as a probable major source of MPs in our diet, we point out the relevance of fruit and vegetables and grains, which yield the highest estimated daily intake. The summed total daily intake of MPs was estimated to range between 7.7 × 10-3 and 3.8 × 108, with the median value of 721 #MPs/kg of bw/day. The polymeric identity of MPs in food roughly follows production proportions, with PE, PET and PP being the most popular. The influence of the chosen analytical technique on the results was pronounced in some food categories (fruit and vegetables, tap and bottled water). Finally, we provide a set of recommendations for future research on MP exposure from food.