The release of absorbed cadmium and lead by probiotic bacteria during in vitro gastrointestinal digestion: a matrix-dependent process.

The potential release of absorbed metals by probiotics during gastrointestinal digestion has not been thoroughly investigated. Therefore, the current study aimed to investigate the release rate and bioaccessibility of absorbed cadmium (Cd) and lead (Pb) by Bacillus coagulans and Lactobacillus acidophilus (single strain, living, and heat-inactivated combination) in fruit juice, doogh (fizzy yogurt drink), and mineral water during in vitro digestion model. The results showed that Pb and Cd metals could be released from all strains and matrices under the in vitro digestion model. On day 1, the highest Cd release was in mineral water (19.86 mg/kg, FBC), followed by doogh (5.32 mg/kg) and orange juice (3.9 mg/kg). After 7 days, Cd release in mineral water increased to 30.65 mg/kg. Pb release peaked in mineral water (35.08 mg/kg, FLABC- on day 1). Bioaccessibility reached 25.8% (Cd, FBC) and 31.8% (Pb, FLABC-) in mineral water. Generally, the release of metals was dependent on the type of matrix, the presence of competing ions, pH of the matrix, and the biological state of the adsorbent (alive or inactivated), mechanism of bacterial strains in the release of Pb and Cd, and the storage time. This study highlights the need to evaluate the stability of probiotic-based biosorbents throughout digestion to assess their safety and efficacy for mitigating heavy metal contamination in food.