A 4-year study of plasma ochratoxin A in a selected population in Tokyo by immunoassay and immunoaffinity column-linked HPLC.

Employing a competitive ELISA (cELISA) based on monoclonal antibody and a novel immunoaffinity-column (IAC)-linked HPLC-fluorometry, ochratoxin A (OTA) levels in the plasma of 184 healthy volunteers (130 males, 54 females) were surveyed in Tokyo during the 4 years from 1992 to 1996. It was found that 85% of the cases were positive for OTA except 38% in 1994, and an average value in the positives was estimated as 68 pg/ml. This suggests that the population in Tokyo is exposed to OTA at high frequency, although the level in plasma is far less than that reported in Europe and Canada. A partial contribution of fermented dietary foodstuffs, coffee and wine is suspected as the source of the OTA observed in the human plasma.