Natural occurrence of alternariol and alternariol methyl ether in Spanish apple juice concentrates.

A limited survey of 32 samples of apple juice concentrates, destined for the production of commercial juices, was carried out in order to evaluate the natural occurrence of the Alternaria metabolites alternariol and alternariol methyl ether. A high-performance liquid chromatographic method based on solid-phase extraction columns for extraction and purification of the toxins was used. Both mycotoxins were found as natural contaminants in 50% of the samples analyzed. Levels of alternariol were in the range 1.35-5.42 ng/ml. Alternariol methyl ether was present in most cases only at trace levels, and the highest amount detected was 1.71 ng/ml in one sample.