Anti-aflatoxigenic effect of Lactobacillus rhamnosus and its synbiotic combination of chitosan/ZnO in milk

Aflatoxin contamination of milk is a serious health concern. When animals ingested food contaminated with aflatoxin B1 (AFB1), it would be converted into aflatoxin M1 (AFM1) and secreted in the milk. This carcinogenic and hepatotoxic toxin could be overcome by biological methods. Therefore, this study aimed to assess the anti-aflatoxigenic effect of the probiotic Lactobacillus rhamnosus (L. rhamnosus) ATCC 7469, as well as its synbiotic combination with chitosan ZnO nanocomposite using ELISA. This is carried out by measuring AFM1 concentration in 90 milk samples, including 73 raw and 27 powdered milk samples. The average AFM1 concentration was 11.22 ± 11.31 and 10.62 ± 8.08 µg/kg, which exceeded the international regulatory limits for raw and powdered milk, respectively. All milk samples were treated with L. rhamnosus ATCC 7469 and a synbiotic combination of chitosan/ZnO nanocomposite and L. rhamnosus ATCC 7469. The results showed that the probiotic L. rhamnosus ATCC 7469, and the synbiotic combination significantly reduced the AFM1 concentration in milk (p value ≤ 0.05). The used probiotic bacteria showed binding to AFM1 from 10 to 83.8%, while the binding range increased to 34-92% after treating milk with the synbiotic combination. In conclusion, the biological treatment of milk using the probiotic, L. rhamnosus ATCC 7469, alone or in combination with chitosan/ZnO nanocomposite, is an efficient method for reducing the AFM1 concentration in milk. This study highlights the use of both metal nanoparticles (as a prebiotic) and probiotics, forming a synbiotic approach to control milk contamination with aflatoxins in the laboratory.