Mechanistic insight into ochratoxin A adsorption onto the cell wall of Lacticaseibacillus rhamnosus Bm01 and its impact on grape juice quality

The contamination of food products with ochratoxin A (OTA) is a significant and pervasive food safety concern. In this regard, the novel use of lactic acid bacteria (LAB) to eliminate OTA from food has shown strong potential. The adsorption of OTA to the Lacticaseibacillus rhamnosus Bm01 (Bm01) cell walls has been demonstrated to eliminate OTA from grape juice effectively. The present study investigated the specific components of the Bm01 cell wall on OTA adsorption and evaluated the effect of Bm01 on grape juice quality using high-performance liquid chromatography. The results showed that the treatment of methanol and formaldehyde caused cell membrane perforation and enhanced OTA adsorption of Bm01, which reduced 98.35% and 95.13% of OAT, respectively. The involvement of cell wall proteins in the adsorption of OTA was demonstrated because only 5.23% of OTA was removed by Bm01 without cell wall proteins. Lactic (from 0 to 1.69 mg/mL) and acetic acid levels (from 0.14 to 1.45 mg/mL) were increased, malic acid (from1.24 to 0.81 mg/mL), glucose (from 8.8 to 6.91 mg/mL), and fructose (from 12.73 to 7.47 mg/mL) levels were reduced after treatment with Bm01. The addition of Bm01 shows little negative impact on color and light transmission. Overall, the effect of the addition of Bm01 on the quality of grape juice was found to be minimal. These results indicate that Bm01 has the potential to be a viable biological solution for mitigating OTA contamination in beverages, thereby offering a practical and effective method for food safety.