Unreported Aflatoxins and Hydroxylate Metabolites in Artisanal Oaxaca Cheese from Veracruz, Mexico

Abstract

Aflatoxins (AFs) are toxic secondary metabolites of the fungi Aspergillus flavus, A. parasiticus and A. nomius. The fungi produce these AFs in cereals, oilseeds and spices. AFs have damaging effects on all organisms, including humans, and their symptoms can be classified as acute (vomiting, hemorrhage and death) or chronic (immunodepression, Reye syndrome, Kwashiorkor, teratogenesis, hepatitis, cirrhosis, and various cancers). The common AFs (AFB1, AFB2, AFG1, AFG2) are metabolized in the liver or by microbes that produce hydroxylates (AFM1, AFM2, AFP1) and aflatoxicol (AFL), which makes them soluble in water. This means that AFs can be excreted in fluids such as milk or urine, and AFs are not destroyed in the process of making cheese. Other AFs can also be excreted in milk, but they have not been reported until now. The purpose of this study was to identify and quantify the AFs present in 30 samples of artisanal Oaxaca-type cheese sold in the City of Veracruz. The average concentrations of AFs detected in the 30 samples of artisanal cheese were AFB1 (11.2 ng g-1) in 77% (23/30); AFL (19.1 ng g-1) in 70% (21/30); AFG2 (0.2 ng g-1) in 63% (19/30); AFM1 (3.0 ng g-1) in 53% (16/30); AFP1 (0.1 ng g-1) in 50% (15/30); AFM2 (0.2 ng g-1) in 20% (6/30); AFG1 (0.03 ng g-1) in 13% (4/30); and a trace amount of AFB2 (