Nickel in foods sampled on the Belgian market: identification of potential contamination sources

Nickel can occur in plant-based, animal-based foods and drinks. It can either naturally occur in plants or it could originate from contamination. The natural occurrence of nickel arises from the fact that the element plays an essential role in the functioning of enzymes involved in the nitrogen fixation process. Besides, contamination can occur at any stage of the production, processing or packing of the foods. More specifically, nickel can leach from contact materials to foods or drinks before their consumption by humans. In recent years, the European Food Safety Authority expressed concern regarding the chronic and acute exposure of the European population to nickel. This study aimed to screen foods available on the Belgian market for their nickel content and to identify potential sources of the contamination. In total, 708 samples were collected from three different main categories of foods, including plant-based products, animal-based products and drinks. Elevated nickel concentrations were found in plant-based products such as chocolate, legumes, nuts, figs, peanut butter, chocolate spreads and breakfast cereals. The nickel concentrations in the animal-based products and drinks were significantly lower compared to the plant-based products. In the beer samples, no correlation between the alcohol percentage and nickel concentration was found. Higher nickel concentrations were found in the tea drinks in comparison to other drinks. Furthermore, the effect of packaging, e.g. storage in cans, on the final nickel concentration of the foods was investigated. No effect of the packaging was found, demonstrating that leaching of nickel from packaging materials is not significantly contributing to the nickel content in foods. The results demonstrate high concentrations of nickel in some plant-based food products and further exposure assessment studies are needed to evaluate the risk due to intake of nickel-enriched food products.