This segment recounts the events that brought the problem of OTA contamination of coffee into international focus. This serves to underline how the worlds of academia, national and international food safety regulation, consumer organization and industry can - and often do - work together to resolve food safety problems.

The presence of ochratoxin A (OTA) in green coffee was first reported in 1974 (Levi et al), whereas its presence in the coffee beverage was reported by Tsubouchi in 1988 and Studer-Rohr in 1995. Roasting reportedly destroys between sixty-nine to over ninety percent of OTA present in green coffee under the normal range of commercial roasting [xref] conditions - the residual OTA in roasted coffee is readily extractable in aqueous solution. This situation means that poor hygiene controls in the production of green coffee leading to OTA contamination can have a negative public health impact on the ultimate consumer.

Since 1980, several studies have reported OTA data for raw coffee [xref]. By 1997, data on 625 coffee samples were available, including results of OTA analyses carried out at the Finnish Customs Laboratory for 1996. The distribution of samples origin among the major coffee producing countries shows that in relation to mean export volumes of raw coffee, some producing countries were under-represented whereas others were over-represented. However, grouped into five geographical regions of producing countries, distributions of export volumes and numbers of samples reasonably match.

The overall mean OTA content for the 625 samples of raw coffee was 1.6 ppb; whereas over 85% of the samples were in the lowest category (undetectable up to 2 ppb). The 1-2% most contaminated samples have a large effect on the overall mean value.

Surveillance of green coffee imported into the UK, Finland and Hungary shows that OTA can occur in coffee from most origins and of all major types as washed and unwashed arabicas and robustas, although there seems to be greater occurrence in unwashed or dry-processed coffees.

In the early nineties, EU authorities in Brussels initiated a programme for the harmonization of regulations relating to mycotoxins in foodstuffs - including maximum limits for OTA in foodstuffs such as coffee. At its 23rd session in 1999, the Codex Alimentarius Commission agreed to initiate the development of a code of practice for the reduction of OTA contamination in cereals and maximum levels of OTA in cereals (CCFAC [.pdf]). Within the Codex system, a maximum level for OTA in coffee has not been discussed.