Ochratoxin A

Ochratoxin A (OTA) is a mycotoxin produced by strains of Aspergillus like A. ochraceus, A. niger, and more rarely by A. carbonarius. Penicillium verrucosum and P. nordicum have been reported to produce OTA as well.1, 3, 4 There is not much information regarding the conditions under which these fungi produce the toxin but it is believed that OTA is produced under storage conditions that would favor mold growth.5 The general appearance of OTA producing fungi may vary from yellow-orange (Aspergillus) to blue-green (Penicillium).4 Chemically OTA consist of a para-chlorophenolic moiety containing a dihydroisocoumarin group that is amide-linked to L–phenylalanine.1 OTA is only slightly soluble in water, but it dissolves in ethanol, methanol and acetone.1 OTA like other relevant mycotoxins contaminates a broad variety of feed matrices, like corn, beans, peanuts, oats, barley, wheat and rye.1, 6 OTA is a known contaminant of various foodstuffs like olives, beans, beer, wine, cocoa, coffee, etc.3, 4

Toxicity

OTA is a carcinogenic mycotoxin and was included in group 2B by the IARC in 1993 (substances that are probably carcinogenic to humans).5 This mycotoxin exhibits nephrotoxic (kidney) effects like the degeneration of the convoluted tubule of nephron, renal interstitial fibrosis, decrease in thickness of basal membrane and glomerular hyalinization, anemia, proteinuria, uraemia.1, 2, 5 OTA displays teratogenic, genotoxic and carcinogenic effects (i.e. multifocal hemorrhages in several organs, fibrin thrombi in spleen, brain, liver, kidney and heart).1, 2, 5, 6 OTA is a potent immunosuppressor and immunomodulatory, giving rise to effects like the size reduction of thymus, spleen and lymph nodes, depression of antibody response, changes in immune cells number and function.1, 2, 3 OTA is toxic for embryos (placental translocation has been observed in animals) and it leaves residues in several tissues and animal products (livers, kidneys, spleen).1, 2, 3, 5

Regulation

No regulation exists in the USA. In EU OTA is regulated in food and feed material.7

Table 1. EU legislation regarding OTA in feed material.7
Products intended for animal feedGuidance value in mg/kg (ppm) relative to a feedingstuff with a moisture content of 12 %
Cereals and cereal products0.25
Complementary and complete feedingstuffs for pigs0.05
Complementary and complete feedingstuffs for poultry0.1
References
  1. Frantisek M., Ostry V., Pfohl-Leszkowicz A., Malir J., Toman J. (2016). Ochratoxin A: 50 Years of Research. Toxins (8) 191.
  2. Grenier B., Applegate T.J., (2013). Modulation of Intestinal Function Following Mycotoxin Ingestion: Meta-Analysis of Published Experiments in Animals. Toxins (5) 396-430.http://www.fao.org/docrep/X5036E/x5036E1e.htm
  3. Keblys M., Bernhoft A., Höfer C.C., Morrison E., Jørgen H., Larsen S., Flåøyen A. (2004). The effects of the Penicillium mycotoxins citrinin, cyclopiazonic acid, ochratoxin A, patulin, penicillic acid, and roquefortine C on in vitro proliferation of porcine lymphocytes. Mycopathologia (158) 317–324.
  4. Krska R., Nährer K., Richard J. L., Rodrigues I., Schuhmacher R., Slate A. B., Whitaker T. B., (2012). Guide to Mycotoxins featuring Mycotoxin Risk Management in Animal Production. BIOMIN edition 2012
  5. Marin S., Ramos A.J., Cano-Sancho G., Sanchis V., (2013). Mycotoxins: Occurrence, toxicology, and exposure assessment. Food and Chemical Toxicology (60) 218-237.
  6. Richard J.L., (2007). Some major mycotoxins and their mycotoxicoses - an overview. International Journal of Food Microbiology (119) 3-10.
  7. Commission regulation (EC) No 1881/2006. Communities, The commission of the European (2006).