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Wheat is an important cereal but it is often contaminated with mycotoxins. The natural occurrence of aflatoxin B 1 (AFB 1 ) and sterigmatocystin (STC) was determined in 178 food samples (32 wheat samples and 146 wheat products) purchased from Chinese supermarkets. The methodology was validated, the wheat and wheat products samples were treated with a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). From these samples 18.8% of wheat and 8.2% of cracker samples were contaminated with AFB 1 . Mean levels were 0.06 µg/kg and 0.05µg/kg, respectively. There was no AFB 1 contamination in white bread or whole meal bread. Meanwhile 53.1% of wheat, 59.2% of crackers, 20.8% of white bread and 16% of whole meal bread samples were contaminated with STC. The mean levels were 0.07, 0.79, 0.12 and 0.12 µg/kg respectively. Although the levels were low, this demonstrates the need for more comprehensive surveys for these two mycotoxins in wheat and wheat products from China.

In this study, a simple, fast, sensitive and reliable method was developed for the simultaneous determination of aflatoxin B 1 (AFB 1 ) and sterigmatocystin (STC) in rice, wheat, maize, oat, rye and barley grains based on a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method and liquid chromatography-tandem mass spectrometry (LC-MS/MS). AFB 1 and STC were extracted using 95% acetonitrile in water and cleaned up using N-Propylethane-1,2-diamine (PSA). The method was validated according to the SANCO/12571/2013 regulation of the European Union (EU). Recoveries at three spiked levels of 0.5, 2.5 and 5.0μg/kg ranged from 77.7% to 119.7% and the relative standard deviations (RSDs) were between 1.3% and 12.8%. Limits of detection (LOD) were 0.03 and 0.02μg/kg for AFB 1 and STC, respectively. The limit of quantification (LOQ) was 0.5μg/kg for both AFB 1 and STC. The proposed method was successfully applied to determine AFB 1 and STC levels in ten non-processed rice samples from Guangdong province in China., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

A total of 101 samples of beer from the Chinese market were analysed for the presence of aflatoxin B 1 (AFB 1 ) and sterigmatocystin (STC), using methods based on liquid chromatography-tandem mass spectrometry. The limit of quantification and the limit of detection in beer were 0.1 and 0.03 µg/kg, respectively. Recoveries of AFB 1 and STC from spiked beer samples were 97.8-103.6% and 92.7-102.1%, respectively. None of the beer purchased samples were contaminated with AFB 1 or STC.