Screening of foods

Impact of weak X-rays on the quality of organic foods

Stones, cherry pits or plastic particles are not wanted in foods. For this reason, X-rays are being increasingly used in food production to check the end products for foreign bodies. The Forschungsring für Biologisch-Dynamische Wirtschaftsweise ("Research Ring for Biodynamic Subsistence Strategy") is investigating whether the irradiation results in a change to or even deterioration in the quality of the products and to what extent the quality of organic foods for people is negatively affected by this technology. With the project the Research Ring wants to set the ball rolling so that the topic of X-ray detection is discussed more extensively in the organic food sector.

The radiation dose for each product that is normally used in practice is roughly equivalent to 10 to 100 dental x-rays (0.1 to 1 milligray). The level permitted by law for product testing is a dose of up to 500 milligray. If people were exposed to this dose, they would already suffer radiation damage. Foods are officially defined as substances, which explains the relatively high doses of radiation which are permitted in the detection of foreign bodies. X-rays are also used during the manufacture of organic and Demeter products, as irradiation is also permitted for measurement and testing purposes. The only procedure which is prohibited is the use of x-rays for conservation purposes, because in this case the radiation doses are significantly higher. Since there is a widespread belief in the field of organic farming and among consumers that foods carry life within them or are alive, methods used in the sphere of living organisms were therefore used in the studies on the effect of radiation.

Since the Research Ring is breaking new scientific ground with this project, a wide range of tests have been used to determine the effect of the x-rays on food. The range of analyses ranged from the examination of seedlings with germination tests, through methods used in eco-toxicology research with algae and duckweed, to cell tests. With an official chemical analysis detection method for food irradiation, products were analysed with respect to changes with several non-living systems. The use of the wide variety of methods was intended to increase the likelihood of being able to detect any potential effects of the x-rays. One particular challenge is the measurement of the indirect effects on humans. This question was approached with a method which is still under development, namely a psychological test for food effects which emerged from a project that was also funded by the MAHLE FOUNDATION.

Most of the methods used were able to demonstrate effects on the foods resulting from treatment with weak X-rays. For example, the irradiation of plant seeds resulted, inter alia, in weight changes in seedlings. With a method that measures light from samples which is reflected back (fluorescence excitation spectroscopy), it was possible to detect differences between treated and untreated plant seeds of wheat, radishes, lettuce and beans. Even if the results so far confirm the effects of legally permitted doses of radiation which are normally used in practice on plants and foods, reliable statements about the effect on product quality are not yet possible. Some of the results have to be confirmed by repeating the tests. Nevertheless, the interest of organic producers and organic retailers in the results is already considerable. Two events for experts have already been held.  


Forschungsring e.V. ("Research Ring Association")

The Research Ring for Biodynamic Subsistence Strategy in Darmstadt is a non-profit institute that conducts research for Organic and Biodynamic Farming. The research ring is one of the pioneering organisations of Organic Agriculture in Germany. There is also close cooperation with the Demeter Registered Association. The main focal points of the research are soil fertility, food quality and specific questions of biodynamic farming.

Who else is involved in the project?

For the processing of this complex issue, the Research Ring was reliant on its partners. Six institutions supported the Research Ring with their expert knowledge and their own methods. The institutions which were involved were the Crystal Lab from the Netherlands, the KWALIS Research Institute from Dipperz, Research and Breeding at the Dottenfelderhof Farming School, the Institute of Complementary Medicine at the University of Bern, the Institute of Biochemical Plant Pathology at the Helmholtz Centre in Munich, and the Institute of Fluid Science from Herrischried in the Black Forest. It was possible for the samples to be treated at the Technical University of Darmstadt.

What are the funds of the MAHLE FOUNDATION specifically used for?

The MAHLE FOUNDATION played a major role in the financing. Much of the research and project organisation was made possible by the Foundation's funds.

Funding period and follow-up project

The MAHLE FOUNDATION has been funding the project since its launch in the autumn of 2013. The results of nine of the ten planned methods are already available. The project will be completed in the first half of 2015.

A follow-up project planned for 2015 will deal with any questions which are still open. In addition to in-depth analyses, surveys of producers and consumers will be processed. The efficiency of X-ray detection is also to be tested. The results will be discussed with experts from the organic food industry and subsequently published. In this way, a better basis for assessing the decisions of manufacturers, dealers and consumers should be created.