Analysis of agricultural commodities and foods for Alternaria mycotoxins

Fungi of the genus Alternaria are parasitic on plants and other organic materials. A. alternata is a frequently occurring species of particular interest because it produces a number of mycotoxins, including alternariol (AOH), alternariol monomethyl ether (AME), altenuene (ALT), altertoxins I, II, and III (ATX-I, -II, and -III), and L-tenuazonic acid (TeA). Cleanup procedures of analytical methods for foods and foodstuffs include solvent partition, generally used for TeA, and solid-phase extraction columns for AOH, AME, and ATX-I. These Alternaria mycotoxins have been determined by TLC, GC, and more usually LC, mainly with ultraviolet detection, although fluorescence and electrochemical detection have also been used for Alternaria toxins other than TeA. A Zn2+ salt is usually added to the LC mobile phase for TeA. Recently, atmospheric pressure chemical ionization and electrospray LC/MS and LC-MS/MS have been applied to the determination and confirmation of AOH and AME in apple juice and other fruit beverages at sub ng/mL levels. Natural occurrences of AOH, AME, and in some cases other Alternaria toxins have been reported in various fruits, including tomatoes, olives, mandarins, melons, peppers, apples, and raspberries. They have been found also in processed fruit products such as apple juice, other fruit beverages and tomato products, wheat and other grains, sunflower seeds, oilseed rape meal, and pecans.