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.

Heavy metal and metalloid poisoning in the environment and food has piqued the public’s interest since it poses significant hazards to the ecological system and human health. In food, several metals, including cadmium (Cd), lead (Pb), mercury (Hg), tin (Sn), manganese (Mn), and aluminium (Al), and metalloids, including arsenic (As), antimony (Sb), and selenium (Se), pose a severe threat to human health. It is of utmost importance to detect even minute quantities of these toxic elements and this must be efficiently determined to understand their risk. Several traditional and advanced technologies, including atomic absorption spectrometry (AAS), spectrofluorimetry, inductively coupled plasma spectrometry, e-tongues, electrochemical aptasensors, Raman spectroscopy, and fluorescence sensors, among other techniques, have proven highly beneficial in quantifying even the minute concentrations of heavy metals and metalloids in food and dietary supplements. Hence, this review aims to understand the toxicity of these metals and metalloids in food and to shed light on the emerging technologies for their detection.

Seaweeds are being consumed more often worldwide and are a source of essential minerals, fiber, vitamins, amino acids, and various bioactive compounds that have many beneficial effects on human health. However, marine pollution and the high capacity of seaweed to absorb metals may mean this food can also be dangerous to human health. The concentrations of some trace elements (B, Ba, Fe, Ni, Li, and V) and toxic metals (Al, Cd, and Pb) were determined in various species of wild seaweeds in the Phaeophyta group of brown algae from the Atlantic Ocean. Inductively coupled plasma atomic emission spectrometry revealed high concentrations of Al (256 mg/kg dry weight), Pb (3.92 mg/kg dry weight), and Cd (0.20 mg/kg dry weight) in Padina pavonica. Pb contributed the most to the tolerable daily intake (TDI) of toxic metals in these samples; 57.2 and 45.3% of the TDI for Pb was found in 5 g of dehydrated P. pavonica and Halopteris scoparia, respectively. This percent contribution is half of the recommended ...