Adsorption efficiency of sodium & calcium bentonite for ochratoxin A in some Egyptian cheeses: an innovative fortification model, in vitro and in vivo experiments

The incidence of the mycotoxin ochratoxin A (OTA) in cheeses constitutes a significant economic and health concern for producers and consumers alike. Recently, detoxification approaches using food additives to counteract mycotoxins have been widely recommended in the food industry. This study aimed to quantify OTA levels in some Egyptian cheese types, and experimentally determine the detoxification effect of bentonite both in vitro and in vivo. The examined Roomy and Karish cheese showed higher OTA levels (4.138 and 3.399 mu g/kg, respectively) than other cheeses. Calcium bentonite presented higher adsorption efficiency than sodium bentonite at all concentrations, both in phosphate buffered saline (PBS) and feta cheese, and at the whole pH range. Calcium bentonite concentrations (60 and 100 mg/ml) had much higher sequestering activity on OTA both in PBS and feta cheese, while the adsorption efficiency was higher at pH 6.8 than at pH 3. All enzymatic activities were near the control levels in rats treated both with OTA and bentonite compared with rats treated with OTA alone. The IC50 of calcium bentonite was 107.75 mu g/ml, which was less cytotoxic than sodium bentonite (52.96 mu g/ml). Bentonites were categorised by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) as excellent binders of OTA. The innovative calcium bentonite-fortified feta cheese showed the most superior sensorial properties; hence it can be predicted as a novel food-grade adsorbent for OTA sequestration.