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Over a period of 8 years (2000-2007), wheat (n = 407) and rye (n = 510) samples of integrated and organic cultivation in the Federal State of Brandenburg were analyzed by HPLC for the Fusarium toxins deoxynivalenol (DON) and zearalenone (ZEA). In the years 2002 and 2007, the overall contamination level was higher than in the other years. The percentage of DON-positives (>50 µg/kg) varied from 5 to 86%, the median and maximum levels varied from 50 to 380 µg/kg and from 50  to 10,400 µg/kg, respectively. The percentage of ZEA-positives (>3 µg/kg) varied from 2 to 41%, the median and maximum levels varied from 8 to 84 µg/kg and from 10 to 451 µg/kg. In the 8 years of testing, frequency and levels of DON and ZEA were significantly lower in cereals of organic cultivation compared with cereals of integrated cultivation.

The extraction of naturally contaminated maize-based products using methanol / water (3+1) or methanol / 0.1 M hydrochloric acid (3+1) produced varying results. Compared with methanol / water extraction tested in IUPAC/AOAC intercomparison studies, as a rule acid extraction achieves a higher fumonisin content. Strong anion exchange columns are very effective for the analysis of untreated maize, such as maize grits or maize meal. This method guarantees satisfactory extract purification. In products with a high fat content (such as maize based snack products) or cornflakes, SAX columns were not particularly effective. For there immunoaffinity columns provide a highly selective extract purification and achieve a very pure chromatogram. Immunoaffinity columns were also used on cornflakes as they achieved better results than the SAX columns.

Bearing in mind the high toxicity of T-2 and HT-2 toxins which occur in cereals (mainly in oats) EU plans legal limits for these mycotoxins. The occurrence data are insufficient because reliable and sensitive analysis methods are not available.A sensitive HPLC gradient method was developed which is applicable with common HPLC equipment (HPLC with fluorescence detection). After extraction of the toxins from sample matrix with methanol/water the diluted extracts were cleaned-up using immunoaffinity columns and then derivatized with 1-anthroylnitrile/DMAP. The T-2 and HT-2 toxins were separated from peaks of the cereal matrix and derivatization reagent by means of a relatively complex HPLC gradient method. The method was validated for oats, wheat, rye, barley, and maize. The recovery rates were in the range of 70-99%, the precision (RSDR) of 3-8%. The limits of detection of T-2 and HT-2 toxins were 1 μg/kg. A total of 119 samples of cereals and cereal products was analyzed according to the optimized method. The analyses of 54 samples of dehulled oats and of 11 samples of processed oat products from food industry had a contamination frequency of 100%. The contents (sum of T-2 and HT-2 toxins) amounted to 3 to 174 μg/kg for the dehulled oats and to 4 to 48 μg/kg for the processed oat products. 29 samples of maize and maize products had a contamination frequency of 80% (2-106 μg/kg in the sum of T-2 and HT-2 toxins). In the samples of wheat and barley the toxins were detected only occasionally (contents: 1-10 μg/kg), in rye not at all.

To avoid fat deterioration in grain products during storage the cereal inherent enzymes lipase, lipoxygenase and peroxidase have to be inactivated. Known methods for the determination of the enzymes activity are tested and their applicability evaluated. Own optimized methods are presented. In laboratory and semiindustrial extrusion tests (laboratory single screw extruder, twin screw extruder, short screw extruder) the degree of enzyme inactivation of wheat bran, rye and maize bran, and oat bran is determined in dependence on the extrusion parameters. The enzymes mentioned already had been inactivated at mild extrusion conditions (temperature < 120 degrees C, moisture 20%, low mechanical stress). Only in brans of high fat content (10-14%) or high moisture (> 25%) minor residual activities of peroxidase and lipase were observed.

A new method for citrinin was developed and validated, which is based on solid phase extraction with polyamide columns and HPLC with fluorescence detection. Sufficient skill with the method given, precise results, i.e. variation coefficients <10%, will be achieved. The mean recovery rates were in the range 74 - 90%. The detection limits of the method determined according to DIN 32645, at good precision, were 1 µg/kg for wheat, rye, barley, maize, and oats. The analysis of several samples containing ochratoxin A (OTA) showed that citrinin is present in brans, wheatings and shorts containing a higher ratio of the outer layers of the grain kernel; both OTA and citrinin were found in in cocoa shells and raisins. Citrinin was detected in 14 OTA-containing samples (1-8 µg/kg). Furthermore, it was demonstrated that citrinin also can be determined in red mold rice according to the new method.