Maximum permitted levels (MPLs) for dioxins and PCBs in animal feeds were introduced in July 2002. These were reviewed in 2004 in the light of new data on dioxins and dioxin-like PCBs in feed materials. The European Commission plans to review the MPLs again no later than December 2006. In anticipation of this, the European Commission has established a collaborative study in which the UK, along with other member states of the European Community (EC), have been requested to analyse a range of animal feeds for dioxin and dioxin-like PCBs.
The University of Reading was contracted to collect the specified number of samples from a range of farms, animal feed merchants and compound feed manufacturers throughout England, Scotland, Wales and Northern Ireland.
A sampling plan was prepared and submitted detailing types of feeding stuffs to be sampled as well as the location, method of collection and data to be recorded. The selection of sources represented a broad spectrum of farms and feed suppliers.
All feed samples were stored in suitable sealed containers, to minimise any risk of subsequent contamination with PCBs and/or dioxins. Dry feeds were stored in cool, dry conditions until delivery to the designated laboratory. Moist feeds (i.e. forages) were stored in sealed containers at -4°C prior to dispatch, and were transported to the designated laboratory in cold-boxes.
In addition to dioxins and PCBs, the European Commission required information on fat and moisture contents of the feed materials. These analyses were undertaken in the laboratory of the Nutritional Science Research Unit according to standard recognised and approved procedures.
Samples were homogenised and aliquots were analysed for the 17 laterally substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and the following PCBs:
-non-ortho-substituted PCBs - International Union of Pure and Applied Chemistry (IUPAC) numbers 77, 81, 126 and 169
-ortho-substituted PCBs - IUPAC numbers 18, 28, 31, 47, 49, 51, 52, 99, 101, 105, 114, 118, 123, 128, 138, 153, 156, 157, 167, 180, 189, 33, 41, 44, 60, 61, 74, 66, 87, 110, 129, 141, 149, 151, 170, 183, 185, 187, 191, 193, 194, 201, 202, 203, 206, 208 and 209.
Blanks and at least one of the following reference materials (results of reference material analysis are reported) were included with every batch of samples: BCR RM 533 (for dioxins), BCR RM 534 (for dioxins) and BCR CRM 350 (for PCBs).
<p>Find more about this project and other FSA food safety-related projects at the <a href="http://www.food.gov.uk/science/research/" target="_blank">Food Standards Agency Research webpage</a>.