Hidden mycotoxins in beer, malt and cereal products
Moulds and their sometimes highly toxic metabolites can be found everywhere in food and can never be avoided completely. A number of analytical methods have already been developed for their detection. In some cases however, precisely these analysis methods can lead to erroneous results and low measured concentrations. As has been shown at the BAM Federal Institute for Materials Research and Testing, deoxynivalenol, a widespread mould toxin, becomes masked during certain processing steps. This mycotoxin particularly affects food products that contain malted grain and beer. "In these products, many of the established analytical methods only provide values for the unmasked poison and 'overlook' the equally important masked substances", BAM food chemist Ronald Maul says.
Toxic metabolites of moulds may seriously damage health when grain products such as mouldy bread are consumed. In animal breeding, they cause feed refusal or reduced growth. It can be assumed that, in addition to mycotoxins, the masked toxins which have been neglected up to now may react similarly. In chemical terms, masking often means the coupling of a sugar molecule to the toxin originally produced by the mould. This results in many analytical methods failing to correctly recognise masked mycotoxins.
Take an example: barley is used for beer brewing. During the brewing process, the mycotoxin content apparently decreases because the masked poison is not detected by the analysis. Nevertheless, the masked mycotoxin still has a toxic effect because it becomes unmasked again in the intestinal tract; that is, it is released. This is what BAM's cooperation partner, the Austrian Department for Agrobiotechnology IFA-Tulln, has found. The body can then absorb it in the unmasked form. "The poison is still there, it just looks different", is how BAM food chemist Maul explains the problem with masked mycotoxins.