Screening and quantification of aflatoxins and ochratoxin A different cereals cultivated in Romania using thin-layer chromatography-densitometry

The main focus of our study was to implement a rapid, inexpensive and reliable method that could be utilized to check the cereals for safety (i.e., screening for total aflatoxins, as well as individual B₁, B₂, G₁, G₂ aflatoxins and ochratoxin A). We developed a protocol by which we were able to isolate mycotoxins from cereals collected from different regions of Romania. After extraction in chloroform, the mycotoxins were separated by thin-layer chromatography (TLC) and quantified using densitometry. Forty-three samples of different cereals (wheat, maize, rye and Triticale) were analyzed. Twenty-five of the 43 samples (58.14% of the total number) were found to be contaminated with different mycotoxins in various concentrations: aflatoxin B₁ (1.6-5.7 μg/kg), aflatoxin B₂ (0.89-4 μg/kg), aflatoxin G₁ (1.2-5.76 μg/kg), aflatoxin G₂ (0.96-3.4 μg/kg) and/or 4.3-30 μg/kg ochratoxin A. The concentration of total aflatoxin contamination ranged from 11.2 to 10.8 μg/kg. Among the different cereals, the highest number of contaminated samples was found to be in the wheat samples (62.5%). The method outlined in this study has been adopted already by our laboratory for current analyses of mycotoxins. The results obtained using this method is in compliance with the strict regulatory guidelines developed both in Romania, as well as in the European Union. Thin-layer chromatography (TLC) is a rapid, inexpensive and convenient method that can be used routinely to screen for mycotoxins. This article describes the detailed procedures for the extraction, purification and quantification of aflatoxins and ochratoxin A, using TLC. Using this method one can identify concomitantly five different mycotoxins and by coupling it with densitometry a quantitative determination is also possible. Therefore, this could become a routine technique in regional laboratories responsible for checking agrifood safety.