Deoxynivalenol Contents in Foodstuffs of Organical and Conventional Production

Organic foodstuffs are defined to be produced under controlled cultivation conditions according to the provisions of the regulation on organic farming of the European community. Grain based foodstuffs of organical and conventional production differ in the cultivation of the basing grain as well as in food processing due to a renunciation of additives in organic products.

Several studies compare the deoxynivalenol (DON) contamination of organical and conventional grown wheat and rye with inconsistent results. Little is known about the situation in foodstuffs.

Therefore occurrence and contents of the trichothecenes nivalenol (NIV), DON, fusarenon-X (FUS-X), 15-acetyldeoxynivalenol (15-ADON), 3-acetyldeoxynivalenol (3-ADON), HT-2 toxin (HT-2) und T-2 toxin (Y-2) in foodstuffs of organic and conventional production were analysed.

Deoxynivalenol CAS 51481-10-8

Materials and Methods

Food samples were collected from food stores in an area within 50 km around the city of Stuttgart. Samples of wheat flour (60 samples) were taken in the first six month of 1999, samples of bread (141 samples) and noodles (67 samples) in the first six month of 1998 and 1999, samples of other products were collected between 1998 and 2001. Samples were milled if necessary; bread samples were dried at 40 ℃ prior to milling. Loss of weight resulting from drying was recorded and toxin contents were calculated based on the original material. Extraction and clean up for trichothecene analysis was carried out as described in detail previously. In brief, extraction was performed with a mixture of acetonitrile and water followed by liquid/liquid extraction with hexane. Clean up was by solid phase extraction using a florisil and a cation exchange cartridge. Derivatization was carried out with trifluoroaceticanhydride and measurement was by GC-MS using a Magnum Ion Trap system in the chemical ionisation mode with isobutane as reactant gas. Detection limits ranged between 2 and 12 μg per kg of food.

Results and Discussion

Based on incidence and levels, DON was the predominant toxin for all groups of foodstuffs with the exception of oats and its products. In this group HT-2 was found in 78% of the samples, DON in 52%.

In organically produced foodstuffs the number of samples positive for DON tended to be lower than in samples of conventional production with the exception of oats and its products as well as rice.

Concerning incidence and levels there were no differences with regard to NIV, FUSX, 3- and 15-ADON, HT-2 and T-2 Toxin between the two production methods.

In wheat flour, bread and noodels the median DON-contents where lower in ecological than in conventional products with significant differences for wheat flour and bread. Corn based products showed similiar tendencies, no differences where

found in oats and products, in rice the DON levels in conventional products were lower than in ecological ones. For foodstuffs based on rice, corn and oats no statistical calculation was carried out because of the limited number of samples.To estimate toxin uptake of the consumer Eriksen and Alexander propose the use of a corrected mean corresponding to SCOOP principle. To calculate this corrected mean negative samples are included using the value of half of the detection limit (4 μg DON/kg in this case). For wheat flour and bread the corrected mean of DON concentration was lower for ecological than for conventional products. For noodles the value for ecological products was higher. This is caused by two samples with high DON levels (> 3000 μg/kg) out of the group of noodles of ecological production.

Differences between conventional and organical products may be due to different cultivation methods of the basing grain on the one and to differences in production method on the other hand. For example yeast can not be used to produce “organic” wholemeal wheat or rye bread varieties and must be substituted by sourdough, leading to changes in bakery processing. Different DON contents in the basing grain may be explained by differing cultivation methods: organic products of plant origin are grown without the aid of chemically synthetic pesticides and largely without the use of readily soluble fertilisers within a diverse range of crop rotation with small share of corn and extensive soil tillage and

the use of resistent sorts. With bread being the main foodstuff based on grain, DON contents in this product are the decisive factor for the contamination of the consumer. In this study the corrected mean for ecological bread was approximately one third of that of conventionally produced bread. Further studies to evaluate the human DON exposition out of organically or conventionally produced foodstuffs are urgently needed.

Reference:

1. Schollenberger*, H. – M. MiJller, W. Drochner. Mycotoxin Research,Vol. 19 (2003)

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