Endocrine disruptors in milk and dairy products – occurrence, levels and risk assessment

Background: The use of plastics in food industry (production, processing, packaging) is related with a risk of migration of some undesirable chemicals into a product. The majority of these migrants are classified as endocrine-disrupting chemicals (EDCs) that can interfere with the endocrine system, thereby contributing to a range of health complications in humans. Milk and dairy products are especially subjected to this threat because of its popularity, high consumption among consumers. Therefore, the aim of this study was to evaluate the presence of 37 ED contaminants in 97 dairy products (yoghurts, buttermilks, kefirs, creams, condensed milks) available on the retail market. Basic procedures: The samples were prepared using a modified QuEChERS technique, followed by gas chromatography coupled to mass spectrometry (GC–MS). Composition of dairy products were also tested. Main findings: The most frequently identified compounds were diethyl phthalate (DEP), isobutyl phthalate (DIBP), dicyclohexyl phthalate (DCHP), 2,4-ditert-butylphenol (2,4-DtBP), benzophenone, bisphenol AF (BPAF) and acetyltributyl citrate (ATBC). Bisphenols A, E, G, M and S, as well as certain phthalates including DEHP, were not detected. Only four samples contained bisphenol A at levels from 1.73 to 20.4 μg/kg. The highest levels of the compounds were found for 2,4-DtBP (42.6–3580 μg/kg) and BPAF (9.2–254 μg/kg). The obtained values did not exceed the specific migration limits (SMLs) established by European Union. Fermented products and those with a high fat content exhibited significantly higher levels of EDCs as well as the use of polystyrene packaging. In health risk assessment, the highest values were obtained for milk, kefir and condensed milk, which posed a potential health risk, particularly to infants and young children. Principal conclusions: Although the consumption of dairy products is highly recommended, it is important to select packaging that minimises the migration of endocrine-disrupting chemicals (EDCs) and to avoid including processed products in children's diets, such as condensed milk, as well as products that have been fermented or that contain high levels of fat. We showed for the first time that dairy products may contain high levels of 2,4-DtBP and ATBC, the substances previously considered harmless and currently being reconsidered in the context of their negative impact on health. The results also indicate that for certain compounds, such as BPAF, there is a strong need to establish TDI values that could provide a more accurate estimation of the health risks to consumers.