Ganzheitliche Untersuchungsmethoden zur Erfassung und Prüfung ...

Summary
The growing market of organic food products demands for product oriented quality control. One
major concern is the differentation of organically grown from conventionally grown food. Therefore
the aims of the project were:
1. to validate certain holistic methods according to ISO 17025 (documentation and
characterisation of each single method) and
2. to test which method can differentiate products from different farming systems statistically.
Both aims could be achieved. Based on documented and tested laboratory procedures samples from
different farming systems (defined field trials, e.g. DOC-trial at FIBL/CH) could be successfully
discriminated by several methods.
The project was coordinated by the Department of Organic Food Quality and Food Culture at the
University of Kassel, whose assigment also was to validate the copperchloride-crystallisation
technique and to measure phenolic compounds. The private research company KWALIS GmbH at
Dipperz was responsible for the validation of the fluorescence excitation spectroscopy and the
physiological aminoacid status, whereas the second private company EQC GmbH at Weidenbach
validated the electrochemical measurements. The validation expert Dr. Kromidas, Saarbrücken,
gave advice on the validation procedures.
All methods were tested with coded samples for their capability to wether they can differentiate
food samples from different farming systems as well as food samples from variety trials. The
samples have been coded and sent around at the same time from a third independend institution
(OEL-FAL, Trenthorst). Therefore the results achieved from different methods could be compared.
The methods “copperchloride-crystallisation”, “fluorescence excitation spectroscopy” and
“physiological aminoacid status” were able to discriminate and group all samples. In addition with
the methods “fluorescence excitation spectroscopy” and “physiological aminoacid status” it was
even possible to identify correctly which sample was from which agricultural system. Future
projects will show, if these methods are also able to differentiate food products from organic versus
conventional farming system when samples are collected from the market rather than being under
controlled conditions.