Special issue: Masked mycotoxins

Abstract

In 1990, Gareis et al. referred to a zearalenone-glycoside as a ‘masked mycotoxin’ to emphasise the fact that this mycotoxin conjugate was not detected by routine analysis of food or feed, but probably contributed to the total mycotoxin content and subsequent effects. Indeed, pigs fed with mixed feed, artificially contaminated with synthesised zearalenone-4-ß-D-glucopyranoside, excreted zearalenone (ZEA) and α-zearalenol in their faeces and urine, demonstrating release of the aglucone during digestion. Earlier, in 1988, Engelhardt et al. demonstrated that wheat and maize cell cultures were able to transform ZEA to the ß-D-glucopyranoside-conjugate as part of their plant metabolism. It is generally known that plants can reduce the toxicity of phytotoxic compounds by chemical modification. This plant detoxification process includes the conjugation of mycotoxins to polar substances such as sugars, amino acids and sulphate, and subsequent storage of the conjugates in cell vacuoles. In 2002, Schneweis et al. described the natural occurrence of zearalenone-4-glucoside in wheat, while in 2005, Berthiller et al. published the first report on the natural occurrence of deoxynivalenol-3-glucoside (DON-3G) in maize and wheat samples. Since then, research on masked mycotoxins has grown exponentially. Besides plant metabolism, food technological processes also have an impact on the masking mechanism, specifically in cereal-based products in the case of fumonisins (Humpf and Voss, 2004; Dall’Asta et al., 2008) and deoxynivalenol (DON) (Lancova et al., 2008).