Ochratoxin A (OTA) is a mycotoxin. It is a well-known nephrotoxic agent and has been associated with fatal human kidney disease, referred to as Balkan Endemic Nephropathy (BEN). It is also believed to increase the incidence of tumors of the upper urinary tract (JECFA 2001). It is also associated with immunotoxicity and acting as a teratogen which implies it causes serious birth defects.

The International Agency for Research on Cancer (IARC 1993a & b) has classified OTA as possibly a carcinogen (group 2B), based on inadequate evidence for carcinogenicity in humans and sufficient evidence in animals.

Ochratoxin A (OTA) is mainly produced by Aspergillus ochraceus, Aspergillus carbonarius, and Penicillium verrucosum (EFSA 2006).

OTA is often produced in food commodities such as cereal grains and coffee beans when contaminated by these moulds. They are a major cause of concern for these commodities (Batista et al., 2009).

The Situation For Ochratoxin A Formation In Coffee Beans

Coffee is now one of the major beverages throughout the globe. Unfortunately, it is also prone to mould contamination. A. ochraceus is a particularly prevalent mould in coffee beans (Gopinanadhan et al., 2007). The issue occurs because coffee seeds prior to processing are handled poorly, might be dried in unhygienic conditions ore allowed to become wet during transport and storage (Blanc, 2005).

The United Nations Organizations such as the FAO/WHO/UNEP (1999) recommended that coffee is dried to a moisture level below 10%. During low temperature (<20 °C) storage, the water activity is required to be maintained below 0.70 to control fungal infestation (Magan et al., 2003). 

Limits

The maximum limit permitted for OTA is 20, 10, and 5 ppb for green coffee beans, instant coffee, and roasted coffee, respectively (Gopinanadhan et al., 2007).

References

Batista, L.R., Chalfoun, S.M., Silva, C.F., Cirillo, M., Varga, E.A., Schwan, R.F. (2009) Ochratoxin A in coffee beans (Coffea arabica L.) processed by dry and wet methods. Food Control 20 pp. 784–90.

Blanc, M. (2005) Green coffee transport and the risk of mold development. Indian coffee 68 pp. 24–6.

European Food Safety Authority (EFSA). (2006) Opinion of the scientific panel on the contaminants in the food chain on a request from the commission related to ochratoxin A in food. EFSA J. 365 pp. 1–56

FAO/WHO/UNEP. 1999. Mycotoxin prevention and decontamination, HACCP and its mycotoxin control potential: an evaluation of ochratoxin A in coffee production. 3rd Joint FAO/WHO/UNEP international conference on mycotoxins. Available from: ftp://ftp.fao.org/es/esn/food/myco6c.pdf.

Gopinandhan, T.N., Velmourougane, K., Panneerselvam, P., Keshamma, E., Raghuramulu, Y. (2007) Occurrence of ochratoxin-A (OT-A) in green and commercial coffee samples. J. Food Sci. Technol. 44 pp. 247–9.

International Agency for Research on Cancer (IARC) (1993a) Some naturally occurring substances: food items and constituents, heterocyclic aromatic amines and mycotoxins. In: IARC monographs on the evaluation of carcinogenic risks to humans, vol. 56. Lyon, France: IARC Press. p 245–395.

International Agency for Research on Cancer (IARC) (1993b) Evaluation of carcinogenic risks to humans. IARC Monographs.  56 pp. 489–521.

Joint FAO/WHO Expert Committee of Food Additives (JECFA). 2001. In Ochratoxin A, in “Safety evaluations of specific mycotoxins.” In: Prepared by the Fifty-sixth Meeting of the Joint FAO/WHO Expert Committee on Food Additives, February 6–15, Geneva.

Magan, N., Hope, R., Cairns, V., Aldred, D. (2003) Post-harvest fungal ecology: impact of fungal growth and mycotoxin accumulation in stored grain. Eur. J. Plant Pathol. 109 pp. 723–30.