Determination of aflatoxin levels in nuts and their products consumed in South Korea

A total of 85 nuts and their products marketed in South Korea were assessed for aflatoxins using a monitoring scheme consisting of enzyme-linked immunosorbent assay (ELISA) for rapid screening, high performance liquid chromatography (HPLC) for quantification and LC-mass spectrometry (MS) for confirmation. Thirty-one out of 85 samples gave ELISA readings above 0.06 and were screened as possible positive samples. Aflatoxin contents of possible positive samples were determined using HPLC with a detection limit of 0.08-1.25 mu g/kg and a quantification limit of 0.15-2.50 mu g/kg. Nine samples including I raw peanut, 4 roasted peanuts, 2 peanut butters, I pistachio and I seasoned assorted nut. were contaminated with aflatoxins (10.6% of incidence), ranging in various levels up to 28.2 mu g/kg. LC-MS analysis on contaminated samples revealed that peaks eluting at 4.4, 5.2, 9.1 and 11.9 min were confirmed as aflatoxin G(1), aflatoxin B-1, aflatoxin G(2) and allatoxin B-2, respectively. (c) 2006 Elsevier Ltd. All rights reserved.