Effect of dietary acids on the formation of aflatoxin B2a as a means to detoxify aflatoxin B1

Aflatoxin B-1 (AFB(1)) is a class 1 carcinogen and a common food contaminant worldwide with widely uncontrolled human exposure. The ability of organic acids to transform AFB(1) into a known detoxified form, aflatoxin B-2a (AFB(2a)), was investigated using high performance liquid chromatography-electrospray ionisation-time of flight mass spectrometry (HPLC/ESI/TOF/MS). The identity of the transformation product was confirmed by accurate mass measurement, chromatographic separation from other aflatoxins, H-1-nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. Of the weak acids tested, citric acid was found to be the most effective for AFB(2a) formation. At room temperature, 1M citric acid was able to convert >97% of AFB(1) to AFB(2a) over 96h of treatment. Up to 98% transformation was achieved by boiling AFB(1) in the presence of citric acid for 20min. AFB(1) hydration after ingestion was explored by spiking AFB(1) into simulated gastric fluid containing citric acid. Under these conditions, > 71% of AFB(1) was hydrated to AFB(2a) and did not show any reversion to the parent compound after being transferred to a neutral solution. These results provide a basis for a practical and effective method for detoxification of AFB(1) in contaminated foods.