Surveys of rice sold in Canada for aflatoxins, ochratoxin A and fumonisins.

Approximately 200 samples of rice (including white, brown, red, black, basmati and jasmine, as well as wild rice) from several different countries, including the United States, Canada, Pakistan, India and Thailand, were analysed for aflatoxins, ochratoxin A (OTA) and fumonisins by separate liquid chromatographic methods in two different years. The mean concentrations for aflatoxin B(1) (AFB(1)) were 0.19 and 0.17 ng g(-1) with respective positive incidences of 56% and 43% (≥ the limit of detection (LOD) of 0.002 ng g(-1)). Twenty-three samples analysed in the second year also contained aflatoxin B(2) (AFB(2)) at levels ≥LOD of 0.002 ng g(-1). The five most contaminated samples in each year contained 1.44-7.14 ng AFB(1) g(-1) (year 1) and 1.45-3.48 ng AFB(1) g(-1) (year 2); they were mostly basmati rice from India and Pakistan and black and red rice from Thailand. The average concentrations of ochratoxin A (OTA) were 0.05 and 0.005 ng g(-1) in year 1 and year 2, respectively; incidences of samples containing ≥LOD of 0.05 ng g(-1) were 43% and 1%, respectively, in the 2 years. All positive OTA results were confirmed by LC-MS/MS. For fumonisins, concentrations of fumonisin B(1) (FB(1)) averaged 4.5 ng g(-1) in 15 positive samples (≥0.7 ng g(-1)) from year 1 (n = 99); fumonisin B(2) (FB(2)) and fumonisin B(3) (FB(3)) were also present (≥1 ng g(-1)). In the second year there was only one positive sample (14 ng g(-1) FB(1)) out of 100 analysed. All positive FB(1) results were confirmed by LC-MS/MS.

Survey of aflatoxins in beer sold in Canada.

Between March 1998 and March 2002, 304 samples of domestic (Canadian) and imported beers from 36 countries were picked up for the determination of aflatoxins B1, B2, G1 and G2. Twelve samples were positive with aflatoxins greater than the limit of quantitation (LOQ) (aflatoxin B1, 4.4 ng l(-1); aflatoxin B2, 3.4 ng l(-1); aflatoxin G1, 11.2 ng l(-1); and aflatoxin G2, 6.2 ng l(-1)). Five samples from Mexico, two samples from Spain and one from Portugal contained aflatoxin B1. Four samples from India contained aflatoxins B1 and B2. The remaining samples contained less than the LOQ for aflatoxins B1, B2, G1 and G2. The analytical method for this survey was based on that of Scott and Lawrence (Scott PM, Lawrence GA. 1997. Determination of aflatoxins in beer. Journal of AOAC International 80:1229-1234.). Aflatoxins B1, B2, G1 and G2 were determined at parts per trillion (ng l(-1)) levels in beer by immunoaffinity column cleanup followed by derivatization with trifluoroacetic acid and reversed-phase liquid chromatography with fluorescence detection.