Recently attention has been drawn on the presence of polychloro dibenzo-p-dioxins (PCDDs) and polychlorodibenzo furanes (PCDFs) in dairy products. Trade has been hampered because of the suspected presence of higher contents of such contaminants in milk powder, cheese, etc. In some countries incineration plants have been closed because of the presence of dioxins in milk from cows grassing in the surroundings.
The determination of dioxins in food products necessitates sophisticated equipment such as High Resolution Mass Spectrometry (HRMS) and High Resolution Gas Chromatography (HRGC). Sensitivities of 0.1 pg/g have to be achieved in order to accurately determine levels of 6 pg TEC/g fat in milk (TEC = toxic equivalent concentration). This latter content is the maximum tolerable limit for the milk in certain countries (e.g. NL). The extremely low levels to be determined often result in disagreement of the results of the analyses. Therefore doubt has been raised on the validity of the results of the determination of PCDDs and PCDFs and on the quality of the monitored dairy products within the E.C. The necessity has been demonstrated to set up a network of well trained laboratories involved in dioxin determinations in food and feed. This network should possibly cover all Member States.
Some laboratories acting upon request of their national authorities have proposed to the Commission to start a project, within the framework of the BCR programme, on the determination of PCDDs and PCDFs in milk. This project should establish the state of the art of such determinations and should help laboratories to improve the quality of their measurements. A first intercomparison on PCDDs and PCDFs will establish the state of the art of the determination of such compounds in milk. Three batches of freeze-dried milk powder will be prepared - one natural milk powder (approx. 2 pg TEC/g fat of dioxins) - two PCDDs and PCDFs enriched samples (approx. 6 pg TEC and 20 pg TEC/g fat). According to the results of the intercomparison, additional exercises will be envisaged to increase the quality of the measurements. Possibly a milk powder, whenever necessary, will be certified for the PCDD and PCDF content.
1st intercomparison concluded
Funding SchemeCSC - Cost-sharing contracts
2600 JA Delft
NR4 7UQ Norwich
3720 BA Bilthoven
1018 WV Amsterdam