The content of 20 trace and minor elements in soy and dairy yogurts consumed in Spain has been determined
using inductively coupled plasma-mass spectrometry (ICP-MS) after microwave digestion. This work presents
two goals: a) to determine the nutritional value in terms of minor elements content, using recommended
daily allowance data; b) to determine the levels of trace toxic elements and compare them with the acceptable
daily intake values. The developed analytical method was validated by using both milk certified reference
materials and recovery experiments over different yogurt samples, obtaining satisfactory results in all cases. In
addition, a comparison between the levels of minor elements found in soy and dairy yogurts was performed.
Much higher concentrations of Cu and Mn were found in soybean products (up to 30-fold higher) and
minor differences were observed in the content of Fe and Zn. Other minor element found at higher concentrations
in soy yogurts was Ni (effect usually observed in plant-origin foods), which was determined at
levels up to 450 ng g−1 in some samples. Finally, the levels of toxic elements were very low, even below
the detection limit in some cases.