Study of human exposure to ochratoxin A and assessment of possible sources.

The first study carried out in the CSFR covered 644 samples of blood sera from the district of Uherské Hradistĕ (about 1,000 km2 and 150,000 population) during March-May 1990. The samples from the selected persons (over 18 years of age) were collected within 4 sampling weeks. Ochratoxin A (OA) was established densitometrically after the minicolumn separation with HPTLC. The detection limit was about 0.5 microgram OA/l, recovery about 95%. The maximum established value was 12 micrograms OA/l. The value 1 microgram OA/l was exceeded by 12.4% of samples. Seventy-eight per cent of samples were under the detection limit. After stratification of the experimental group (according to sex and age) higher numbers of findings above 1 microgram OA/l were found in the stratum of 30-40 years (males and females) and in the age group over 60 (females). The differences were statistically insignificant (contingency table analysis, alpha > 0.10). The high statistical significance (contingency table analysis) of difference (alpha < 0.01) showed the findings over 1 microgram OA/l, and the date of the sampling week. The graphic analysis (localisation of the results in the map of the area) did not support the hypothesis of the dependence of the results over 1 microgram OA/l on the place of residence. The results do not support the hypothesis on the sites with a higher level of OA contamination in the studied district. We assume the OA hazard sources originating from both the individual and communal food supply.