Microplastics as Emerging Food Contaminants: A Challenge for Food Safety

Abstract

Microplastics (MPs) have been identified as emerging environmental pollutants classified as primary or secondary based on their source. Composition, shape, size, and colour, among other characteristics, are associated with their capacity to access the food chain and their risks. While the environmental impact of MPs has received much attention, the risks for humans derived from their dietary exposure have not been yet assessed. Several institutions and researchers support that the current knowledge does not supply solid data to complete a solid risk characterization of dietary MPs. The aim of this paper is to review the current knowledge about MPs in foods and to discuss the challenges and gaps for a risk analysis. The presence of MPs in food and beverages has been worldwide observed, but most authors considered the current data to be not only insufficient but of questionable quality mainly because of the outstanding lack of consensus about a standardized quantifying method and a unified nomenclature. Drinking water, crustaceans/molluscs, fish, and salt have been identified as relevant dietary sources of MPs for humans by most published studies. The hazard characterization presents several gaps concerning the knowledge of the toxicokinetic, toxicodynamic, and toxicity of MPs in humans that impede the estimation of food safety standards based on risk. This review provides a tentative exposure assessment based on the levels of MPs published for drinking water, crustaceans and molluscs, fish, and salt and using the mean European dietary consumption estimates. The intake of 2 L/day of water, 70.68 g/day of crustaceans/molluscs, 70.68 g/day of fish, and 9.4 g/day of salt would generate a maximum exposure to 33,626, 212.04, 409.94 and 6.40 particles of MPs/day, respectively. The inexistence of reference values to evaluate the MPs dietary intake prevents the dietary MPs risk characterization and therefore the management of this risk. Scientists and Food Safety Authorities face several challenges but also opportunities associated to the occurrence of MPs in foods. More research on the MPs characterization and exposure is needed bearing in mind that any future risk assessment report should involve a total diet perspective.

Microplastic profusion in food and drinking water: are microplastics becoming a macroproblem?

“…[145][146][147][148] Recently, a study ascertained the average microplastic concentration as follows; tap water ¼ 4. 149 The probable route for contamination was assigned to the water source used during the production processes and/or the process of beverage packaging. 78 Similarly, the occurrence of microsized thermoplastic sulphone polymers (overall average 6.5 AE 2.3 particles per L) in milk samples was ascribed to the peeling off of damaged ltration membranes during milk processing.…”

“…The level of microplastic contamination of identified particles, including polyamide, poly(ester amide), acrylonitrile butadiene styrene and poly(ethylene terephthalate) followed the order of beer (152 ± 50.97 particles per L) > soft drinks (40 ± 24.53 particles per L) > energy drinks (14 ± 5.79 particles per L) > cold drinks (11 ± 5.26 particles per L). 149 The probable route for contamination was assigned to the water source used during the production processes and/or the process of beverage packaging. 78 Similarly, the occurrence of micro-sized thermoplastic sulphone polymers (overall average 6.5 ± 2.3 particles per L) in milk samples was ascribed to the peeling off of damaged filtration membranes during milk processing.…”

“…Moreover, they feature the dependence of the immunological response on the compound organization of the plastic, with PET being more toxic in comparison to PE in the respiratory and gastrointestinal tract. 149 In the gastrointestinal tract, the foreseen cellular effect of microplastics will probably be because of adjuvant movement, for example, the upgrade of a currently resistant reaction to surface-adsorbed biomolecules. For instance, in a recent study, when macrophages were given antigens and poisons attached to a microparticle, upgraded T cell expansion was seen in contrast with their dissolvable reciprocals; 96 similarly, the fiery reaction of fringe cells to the endotoxin lipopolysaccharide (LPS) was attributed to TiO 2 nanoparticles.…”

Health risks of environmental exposure to microplastics

“…To date, much attention has been paid to the environmental impact of microplastics, while the health risks of human oral exposure have not yet been sufficiently studied. Several researchers have expressed the view that current knowledge does not provide solid data to reliably characterize the health risks from oral exposure to microplastics [26].…”

The forgotten tonsils—does the immune active organ absorb nanoplastics?

“…Humans are exposed to micro-and nanoplastics through multiple pathways probably mainly through air inhalation (Prata, 2018) and ingestion (Rubio-Armendáriz et al, 2022). Microplastics are commonly defined as plastic pieces with a size <5 mm (Frias and Nash, 2019) and the smallest microplastics are referred to as nanoplastics.…”