Comprehensive investigation of undesired substances and microbial contamination in plant-based drinks

Abstract

There is a growing market relevance of non-dairy alternatives mainly driven by issues concerning an increasing prevalence of vegetarianism, awareness of animal welfare and ecological impact of food production. Among the most popular plant-based drinks (PBDs) are almond-, oat- and soy-based products. As the likeliness of contamination of PBDs varies markedly depending on their plant origin, in a survey of selected most common organic-products from the German market mycotoxins, residues of plant protection products, heavy metals, and microbial contamination have been monitored. The results showed that, with one exception, all products were commercially sterile, free of pathogenic microorganisms and contained at most trace amounts of plant protection agent residues. For nickel especially, soy-based drinks showed elevated levels of up to 315 μg/kg and these products also had the highest cadmium levels of up to 7.2 μg/kg. Oat and almond based drinks contained up to 159 and 54 μg/kg Ni and 1.4 and 0.6 μg/kg Cd respectively. By contrast, for mycotoxins, the soy-based drinks showed almost no detectable contamination, while up to 2.1 μg/L T2+HT2-toxin and 5.5 μg/L deoxynivalenol were quantified in oat-based drinks and up to 130 ng/L aflatoxin B1 (AFB1) were found in almond-based drinks. Additionally, oat- as well as almond-based drinks frequently contained up to 263 ng/L and 70 ng/L of the emerging mycotoxin and AFB1 precursor sterigmatocystin.In particular, the mycotoxins in oat- and almond-based drinks and heavy metals in soy-based drinks should be further investigated and minimized, as PBDs represent a novel and additional source of the overall human exposure to these contaminants.