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

Aflatoxin B1 (AFB1) is a class 1 carcinogen and a common food contaminant worldwide with widely uncontrolled human exposure. The ability of organic acids to transform AFB1 into a known detoxified form, aflatoxin B2a (AFB2a), 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 AFB2a formation. At room temperature, 1 M citric acid was able to convert > 97% of AFB1 to AFB2a over 96 h of treatment. Up to 98% transformation was achieved by boiling AFB1 in the presence of citric acid for 20 min. AFB1 hydration after ingestion was explored by spiking AFB1 into simulated gastric fluid containing citric acid. Under these conditions, > 71% of AFB1 was hydrated to AFB2a 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 AFB1 in contaminated foods.