Ochratoxin A in corn and wheat: geographical association with endemic nephropathy.

Aim. To determine whether the wheat and corn from the Slavonski Brod surroundings, an area of endemic nephropathy related by some investigators to ochratoxin, contained an inceased amount of ochratoxin A. Methods. The presence and amount of ochratoxin A were determined in 92 wheat samples and 51 corn samples from the surroundings of Osijek and Slavonski Brod, Hrvatsko Zagorje, Istria, and Celje surroundings (Republic of Slovenia). Upon sample treatment with organic solvents, identification and quantification of the samples were performed by the method of thin-layer chromatography, whereas high-pressure liquid chromatography was used as a confirmation method. Results. Ochratoxin A was present in 74 of 92 (75.81%) wheat samples and in 17 of 51 (33.33%) corn samples. The results obtained for wheat ranged from 0.019 to 160.00 ug/kg, and for corn from 0.019 to 40.00 ug/kg. The highest mean level of ochratoxin A in wheat was recorded in the samples from the Slavonski Brod surroundings (38, 78+-27, 15 ug/kg), followed by Osijek (8, 713+-8, 28 ug/kg), while the mean ochratoxin A level found in the wheat from Hrvatsko Zagorje was only 2, 07+-1, 47 in Slovenia (1, 33+-2, 56 and 0, 18+-0, 53 ug/kg, respectively). A statistically significant difference was observed between wheat samples from Slavonski Brod and all other groups of samples (p=0.000517, 0.00333 and 0.00018). The surroundings (20, 00+-14, 83 ug/kg), while the levels found in corn from Osijek, Celje, Hrvatsko Zagorje and Istria were considerably lower (0, 81+-1, 35, 0, 70+-1, 93, 0, 42+-0, 41 and 0.40+-0.79 ug/kg, respectively). A statistically significant difference was also observed between the Slavonski Brod samples and all other groups of corn samples (p=0.000506, 0.013278, 0.026374 and 0.000233), however, no statistically significant difference was found between the latter sample groups. Conclusion. By far highest levels of ochratoxin A were recorded in the cereals from the Slavonski Brod surroundings, a known area of endemic nephropathy. The levels of ochratoxin A found in the cereals from the Osijek surroundings, known for the occasional occurrence of endemic nephropathy, were lower, however, they still exceeded (statistically significantly in case of wheat samples) the levels found in the samples collected in other areas where endemic nephropathy had nevr been recorded. Additional studies are needed, and our results suggest the possible association between the genesis of endemic nephropathy and ochratoxin A in cereals. Irrespective of the real association between ochratoxin A and endemic nephropathy, the demonstrated toxicity of ochratoxin A appears to fully justify all efforts towards legal control of its maximal allowed amount in human food.