Production of cyclopiazonic acid has been found in cultures of Aspergillus flavus, A. oryzae, Penicillium camemberti, P. commune, P. dipodomyicola, P gri- seofulvum, and P. palitans (Frisvad et al., 2004; Samson et al., 2010). The toxin is uncommon in brewing cereals and malt but has been detected in maize after infection with P commune, A. flavus and A. orzyzae as a co-contaminant, together with aflatoxins (Gqaleni et al., 1996). No published reports on the compound as a contaminant of beer are available. Owing to structural similarities, symptoms of toxicity encountered in laboratory animals after administration of cyclopiazonic acid were very similar to aflatoxin toxicosis, i.e. hepa- totoxic, nephrotoxic, neurotoxic and carcinogenic effects. So far no legal limits have been adopted for cyclopiazonic acid.
Ochratoxin A (OTA)
Ochratoxin A is produced in cultures of Petromyces alliaceus, Aspergillus carbonarius, A. niger group species, A. ochraceus, A. steynii, A. westerdijkeae, P nordicum and P verrucosum (Samson et al., 2010). P. verrucosum has been identified as the major producer of the toxin in brewing barley where it mostly co-occurs together with the structurally related iso- coumarine mycotoxin citrinin (see above) (Krogh et al., 1973; Hokby et al., 1979; Vrabcheva et al., 2000). Contamination of maize kernels is regularly due to infection with A. carbonarius, A. niger, and A. ochraceus, depending on the origin of the tested materials (Magnoli et al., 2006, 2007). The toxin has been detected in various food products such as cereal products, nuts, coffee, cocoa, wine, grape juice, vegetables, dried fruits and spices. It has been demonstrated to contaminate a high percentage of beer samples although in low concentrations (Visconti et al., 2000; Tangni et al., 2002; Medina et al., 2005; Varga et al., 2005; Bellver Soto et al., 2014). Concentration of the compound has been shown to decrease considerably during mashing and during the brewing process so that 2% to 25% of the original OTA amounts were recovered from the final beer (Krogh et al., 1974; Chu et al., 1975). Ochratoxin A is nephrotoxic, cytotoxic, immuno- toxic, teratogenic and genotoxic (Petzinger and Ziegler, 2000) and has been classified a B2 cancer compound by the IARC (1993). Classification into the group of probably carcinogenic compounds (2A) has been proposed (Kuiper-Goodman, 1996). While the induction of cancer is not proven in humans there are clear indications of a connection to BEN (Vrabcheva et al., 2000). Legal limits for the contamination of food and food raw materials with OTA are in effect in many countries, including the EU, with maximum values ranging from 2.0 to 20 pg/kg in different food sources (van Egmond, 2007). A limit of 0.2 pg/kg has been set up for beer by the European Commission.