Ochratoxin A from a toxicological perspective

Abstract

Ochratoxin A (OTA) is a widespread mycotoxin which is produced mainly by the mould fungi Aspergillus ochraceus and Penicillum verrucosum during the storage of cereals, cereal products and other plant-derived products such as herbs, spices, grapes, etc. By carry over from mouldy fodder, ochratoxin A is also found in pork meat, offal and sausages containing pork blood. When ingested as a food contaminant, OTA is very persistent in human beings with a blood half-life of 35 days after a single oral dosage due to unfavourable elimination toxicokinetics. This renders the toxin among the most frequent mycotoxin contaminants in human blood in the EU, the US, Canada, and elsewhere, where it has been investigated. OTA is neither stored nor deposited in the body, but heterogeneous body distribution may impose serious damage to the kidneys. The toxin was classified a 2B cancer compound, being possibly carcinogenic for humans. It was among the strongest carcinogenic compounds in rats and mice. As the toxicological profile also includes teratogenesis, nephrotoxicity, and immunotoxicity, legislation authorities are currently discussing maximal residue levels (MRL) for OTA in various foodstuffs. In the present article arguments are presented which suggest an acceptable daily intake (ADI) of 1.5 ng OTA/kg body weight and a much lower MRL than 5 microgram OTA/kg cereals and cereal products as has been postulated by the EU commission.

Ochratoxin A contamination of cereal grains and coffee in Hungary in the year 2001

“…Humans may take up OTA by consuming foods made from ochratoxincontaminated cereals and other products such as coffee, beer, wine and foods of animal origin (Kuiper-Goodman, 1991;Jorgensen et al, 1996;Petzinger and Ziegler, 2000). Studies surveying the OTA content of human blood samples have been performed in numerous countries of the world including Hungary, and such surveys have invariably detected a high rate of positivity (BreitholtzEmanuelsson et al, 1993;Kovács et al, 1995;Solti et al, 1997;Scott et al, 1998;Özcelik et al, 2001).…”

“…In addition to the OTA contamination of human blood samples, the occurrence of ochratoxin in human colostrum has also been reported (Breitholtz-Emanuelsson et al, 1993;Kovács et al, 1995). The high rate of contamination found in blood samples was attributed to the common occurrence and unique k inetics of ochratoxin (Petzinger and Ziegler, 2000). StuderRohr et al (2000) found that orally administered OTA doses had a half-life of 840 hours in humans, which is much longer than the half-lives found in any other species.…”

“…StuderRohr et al (2000) found that orally administered OTA doses had a half-life of 840 hours in humans, which is much longer than the half-lives found in any other species. OTA could be detected in the blood even 240 days after a single intake of a high dose (Studer-Rohr et al, 2000;Petzinger and Ziegler, 2000). This unique kinetics of OTA may lead to increased accumulation of this mycotoxin in the human organism.…”

Removal of ochratoxin A by wine Saccharomyces cerevisiae strains

“…Ochratoxin A is very widely detected in raw material and food products such as cereals, bread, coffee, dried wine fruits, as well as in beverages, for example beer, grape juice, and wine [1][2][3][4][5][6][7]. This toxin is produced by numerous fungal species belonging to the genera Aspergillus and Penicillium.…”

Ochratoxin A induces apoptosis in neuronal cells

“…The kidney is the main target tissue of OTA toxicity [10,19]. In addition to its nephrotoxic effects, hepato-, terato-and immunotoxic activities of OTA have also been reported [18,24]. OTA has been classified as a putative human carcinogen by the International Agency for Research on Cancer (IARC [14]).…”