Levels of ochratoxin A in blood from Norwegian and Swedish blood donors and their possible correlation with food consumption.

Blood levels of ochratoxin A were determined in 406 Scandinavian blood donors (206 from Oslo, Norway, and 200 from Visby on the island of Gotland, Sweden), using an HPLC method. In connection with the blood collection, the subjects were asked to fill in a food questionnaire to obtain individual dietary information relevant to ochratoxin A exposure. The mean plasma level of ochratoxin A was 0.18 ng/ml in Oslo and slightly higher, 0.21 ng/ml (P=0.046) in Visby. There was no correlation between plasma levels of ochratoxin A and the estimated total dietary intake of ochratoxin A based on consumption data and levels in food (retrieved from the literature), neither was the plasma level of ochratoxin A correlated with the total amount of food consumed. However, consumption of several foods, including cereal products, wine, beer and pork, were to some minor degree related to high plasma levels of ochratoxin A. The strongest correlations (correlation coefficient r>0.4; P<0.001) were observed for women in relation to the consumption of beer or medium brown bread. Correlation analysis of combinations of two or more food categories did not result in any statistically significant correlation.

Ochratoxin A in rice cultivars after inoculation of Penicillium verrucosum.

The natural occurrence of ochratoxin A in grain samples of 23 rice cultivars was in the range 0.01-1.0 ng g(-1) rice. Samples from the same cultivars were surface sterilized with NaClO, dried to 19% water content and equilibrated at water activity (a(w)) 0.75 and 20 degrees C for 8 days. Varietal differences in equilibrium w/w water content (p < 0.0001) were found, reflected by differences in amylose and protein contents. Samples were then inoculated with an isolate of Penicillium verrucosum with 1 ml spore suspension to each 50 g rice sample; and incubated at a(w) 0.75 and 20 degrees C for 23 weeks. During incubation, ochratoxin A was accumulated in all cultivars. Significant varietal differences in ochratoxin A accumulation were observed (p < 0.0001). Grain samples with less than 19.5% equilibrium water content accumulated less ochratoxin A (p < 0.005). In a multiple regression analysis accumulated ochratoxin A content was expressed as a function of natural occurrence of ochratoxin A (p < 0.05), equilibrium water content at time of inoculation (p < 0.005), 1000-grain weight (p < 0.1), and chalkiness of endosperm (p < 0.05), with p < 0.0001 for the full function. Naturally occurring ochratoxin A was the strongest independent variable with p < 0.0005 for the slope coefficient in single regression. Rice cultivars IR8, IR24, IR620030-18-2-2 and R91-1081-1 had exceptionally low accumulation of ochratoxin A.

Intermediates in the penicillic acid biosynthesis in Penicillium cyclopium.

Feeding experiments using 14C-labelled precurosrs demonstrate the following sequence of the biological formation of penicillic acid in Penicillium cyclopium: orsellinic acid leads to 2-O-methylorsellinic acid leads to 1,4-dihydroxy-6-methoxy-2-methylbenzene leads 6-methoxy-2-methyl-benzoquinone(1,4)leads to penicillic acid.