"Doping" in the shed more difficult now
In the European Union the use of hormones in animal fattening is prohibited. Nevertheless, they are still administered illegally to food-producing animals because of their muscle-building and growth-enhancing properties. Both exogenous and endogenous hormones, which are manufactured synthetically, are administered. Whereas the control authorities have been able to detect exogenous hormones for some time now, this was not the case when it came to the administration of synthetically manufactured, endogenous steroids. They could not be distinguished from the chemically identical hormones that occur in the body. In order to close this gap, a method to detect the illegal use of these "natural" steroids in livestock was developed in a European research project lead-managed by BfR. "Now that the detection gap has been closed the ban on hormones can take effect and be successfully monitored", says BfR President Professor Dr. Dr. Andreas Hensel.
Hormones play an important role in nature: They occur in plants, animals and human beings, steer metabolic processes and already have an impact at low doses. Overly high doses have a negative effect on the target organs and may also increase the risk of tumours. This also applies to the group of steroids which includes the female and male sexual hormones - estradiol and testosterone. Consequently, the use of all hormones is banned in food-producing animals in the European Union. This applies equally to exogenous and synthetically manufactured endogenous substances.
Steroid hormones build muscles and promote growth. That is why they are still repeatedly being used illegally in animal fattening despite the ban. Whereas the exogenous hormones could already be detected for some time now by food control, the illegal use of synthetically produced, endogenous hormones went largely undetected. Up to now they could not be distinguished from the steroids that occur naturally in the body of animals because they are identical to them in chemical terms.
The EU research project ISOSTER aimed at closing this gap. It was initiated and co-ordinated by BfR over a period of four years and has now been concluded. Nine partners from France, the United Kingdom, the Netherlands and Germany took part in the project. They came from food and doping control. The project was financed from funds of the European Union and from the project participants’ own resources.
Within the framework of ISOSTER a detection method has been developed further which is based on IRMS (isotope ratio mass spectrometry). This method is used in sports doping and is now to be made available to food control authorities, too. Isotope ratio mass spectrometry draws on the fact that carbon consists of the two stable isotopes, 12C and 13C. The proportion of the 12C isotope in carbon is approximately 98.89% and that of the 13C isotope only 1.11%. The exact percentage ratio between the two isotopes in the molecules of an organism is influenced by various factors, for instance nutrition. Within an organism, however, it is roughly the same.
As a consequence of the manufacturing process, a synthetically produced hormone, for instance testosterone, contains less 13C than testosterone formed by the body. If an animal is given synthetically manufactured testosterone, it mixes with its endogenous testosterone. This leads to a change in the isotope composition of the testosterone. What we now have is a mixture of the synthetic testosterone and the testosterone formed in the body. This means that the percentage proportion of the 13C isotope determined by isotope ratio mass spectrometry is smaller. The other molecules maintain their original composition. If differences are observed when comparing these values, then the hormone ban has probably been infringed.
The hormone isotope can be detected in the urine of cattle. This means it is possible to undertake controls of animals in the animal sheds. However, this new method is relatively complicated because the concentrations of the hormones in the organism and the proportion of the 13C isotope in the molecule are very low. Furthermore, the hormone to be examined must be separated from all interfering accompanying substances. The method has been successfully tested using samples of treated and untreated cattle in various European laboratories. Only the future will reveal whether this complicated method is suitable for routine use in food control.