POLYCHLORINATED DIBENZO-PARA-DIOXINS AND DIBENZO-PARA-FURANS IN MILK-FAT IN THE FRG

The classification, intended for preventive reasons, of the PCCD/F ori ginating from the environment considered to be also carcinogenic for m an and the resulting high priority of research required for the food s ector in order to minimize consumer's risks has found its expression i n a main research programme of the Institute for Hygiene of the Federa l Dairy Research Centre. The carry-over research undertaken at the Ins titute for decades has allowed the known transfer of these lipophilic, persistent environmental chemicals from feedingstuffs into milk fat t o be quantified in experiments with animals. As expected, a mixture su ch as PCDD/F does not behave in a homogenous manner, even if biologica l transfer processes are taken into account. The observed carry-over r ates range between < 1 and more than 35 %, the mean value being approx , 20 % for the spectrum of those congeners which contribute mainly to a contamination of milk fat. The carry-over factor established as a re sult of the work performed is approx. 4 al this point of the food chai n, this being attributable to the rather good bioavailability of the s upplemented dioxin- and furan contents. Under field conditions a facto r 2 is likely to be more realistic. The limit values for milk fat and feed dry matter which can be derived from the carry-over trials are in dispensable for establishing realistic limits. The interest of the Fed eral Ministry of Food, Agriculture and Forestry in comparable data rel ating to the dioxin- and furan contamination of all foodstuffs - with emphasis being placed on foods originating from animals - based upon l arger sample collectives (approx. 200) and consumer-oriented monitorin g as a basis for taking potential future decisions regarding limits, - has led to cooperative activities in this area, the Institute for Hyg iene disposing of the high resolution mass spectrometer installed in 1 994 being the partner responsible for analytics of the research instit utes respectively responsible for sample regiment. Monitoring of 204 b utter samples throughout the FRG in March 1995 showed a spectrum (iTE) ranging between 0.28-1.19 pg/g fat, the arithmetic mean being 0.68, p gi g. Accompanying studies using tanker bulk milk (north German area) have shown that there exists a distinct downward trend from 0.8 pg iTE /g (1992) to 0.6 pg iTE/g (1995) for milk fat from this region. These findings, as well as the comparatively low contamination of butter hav e shown that the measures for limiting emissions pushed forward since 1991 have produced an effect. The findings obtained using a few human milk samples (9.8-27.2 pg iTE/g fat) reflect the accumulation in human s and emphasize the importance of all of the measures to be taken for minimizing health hazards also as regards infants.