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Development and use recommendations of selected methods for distinguishing between organic and conventional products
Project
Project code: 2808OE023
Contract period: 01.02.2009
- 31.08.2012
Budget: 140,527 Euro
Purpose of research: Applied research
The aim of the study was to evaluate different methods for determining whether a product was produced under conventional or organic conditions. Evaluation was done by defined criteria like reliability of the results for quality assurance and the usability in a control system by inspection bodies and control authorities. For the evaluation three different methods have been chosen:
isotope ratio mass spectrometry (IRMS), Fluorescence activated spectroscopy (FAS) and a profiling technique.
Isotope ratio mass spectrometry (IRMS) is based on the examination of the natural layout of stable isotopes of bio-elements in a product. For example, the ratio of nitrogen isotopes reflects the fertilization and the isotopes of tissue water show the regional and country-specific conditions. Other isotopes like carbon can also be useful to determine where a product originates from. The determination is done by comparing the isotope layout of the product with results from a reference database. Four out of nine products have been used to build up the reference database (wheat, carrots, potatoes and eggs). In this project 816 product samples have been analyzed and compared with 329 blind samples. The results of the sampling show, that a significant differentiation of the products between organic and conventional production could be possible, especially if the results of the different bio-elements were used in combination. A main advantage of this method is that the results can be shown in a probability on how likely it is that the product was produced under organic or conventional conditions.
The FAS method has been used to investigate samples of eggs and wheat. The method is based on a defined process, where light emission is time-dependant measured. In the project 82 samples of eggs and 130 samples of wheat have been tested whether the products have been produced under organic or conventional conditions. Using this method, 90 % of the egg samples and 80 % of the wheat samples could be determined correctly. Wheat samples that have been stored for one year at -26 °C were used for a reproduction of the test results and the ability to germinate has been tested. The results of the tests show, that further investigations are necessary to improve the discriminatory power of the results and the reduction of time needed per sample.
Profiling methods are used to analyze whole types of substances in a product. To analyze the metabolites of organic and conventional wheat samples a gas chromatography-mass spectrometry was used. The metabolite profiling showed a differentiation between the farming system (organic and conventional) as well as a differentiation between year of cultivation and variety. A clear determination between the two farming systems was difficult due to fluctuations in the metabolites resulted in different varieties and growing periods. The fluctuating protein contents of the samples, which are affected by the growing period during a year, are responsible for the heterogenic results.
The evaluation shows that the results of the two methods IMRS and FAS are only reliable if enough reference data for comparison are available. The IMRS method seems to be the best method to determine if a product originates from only one producer, a group of producer or from a defined region. To develop the IMRS method as a reliable instrument to assure product quality it is necessary to standardize the sample taking, the sample preparation and sample analysis as well as the development of a general shared reference database. These needed steps are further investigated in the project 'Wasserzeichen'.
Section overview
Subjects
- Organic Farming
Collaborative Project
Framework programme
Federal Organic Farming Scheme and other forms of sustainable agriculture (BÖLN)
