Determination of heavy metals and health risk assessment of cheese products consumed in Greece

Contamination of dairy products with heavy metals is a major concern on a global scale and human exposure to related food products, especially cheese, is of rising concern. The aim of this study was the determination of several heavy metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se and Zn) in 15 cheese samples consumed in Greece, during March 2016. An analytical method was optimized and applied, using microwave digestion followed by atomic absorption spectrometry. The optimized method produced good performance characteristics, including low LODs, good linearity (R-2 > 0.997) and high recovery (77-114%). Results revealed the presence of low heavy metal concentrations in samples. Two distinct elemental groups were identified using clustering analysis. The first elemental group (Cu, Mn, Zn, Cd, Pb and Se) presented higher contents in hard and salty cheese types, while the second elemental group consisted of Cr, Fe and Ni and exhibited significantly higher concentrations in soft cheeses (water content > 60%). HMs in cheese samples presented low risk to human health. Estimated Daily Intake (EDI) values for Pb, Hg and Cd revealed a minimum exposure of the population to those heavy metals through cheese product consumption. In all cases, THQ values were <1, suggesting that the cheese products under investigation do not present a potential health risk through their consumption. The daily intake (DI) for Zn in cheese products represented 0.50-14.25% of the Recommended Dietary Allowances (RDA) for adults, while for Cu the DI contributed 0.33-10.67% of the RDA values.