Biomarkers of human exposure to ochratoxin A

Low blood serum/plasma concentrations of ochratoxin A (OTA) have been reported for healthy persons in more than 20 countries. Epidemiology studies in Bulgaria, Romania, Spain, the Czech Republic, Turkey, Italy, Egypt, Algeria and Tunisia have found significantly higher serum or plasma levels of OTA in patients with certain kidney disorders compared to healthy people, although the association may not be a causal one. Regional variations within one country, seasonal differences and variation within one person were found in some studies. Correlations with age and gender have not usually been detected. Detection limits using liquid chromatographic methods are about 0.02-0.1 ng ml(-1) plasma/serum so that incidences of positives often are 50-100%, reflecting widespread and continuous exposure of humans to OTA. In a study in the UK, OTA in urine was found to be a better indicator of OTA consumption than OTA in plasma. Nevertheless, blood plasma concentrations have been widely used to estimate dietary intake of OTA, using equations relating it with plasma concentration, plasma clearance and bioavailability. A further source of human exposure is airborne dust. OTA has been detected in human milk in several countries and comparisons with serum/blood levels have been made in Germany and Sweden.