Lab tests on cattle at four Irish farms have found dioxin levels 100-400 times higher than legal limits, way higher than initially thought, according to the Food Safety Authority of Ireland on Thursday (Dec 18).

The result is a sharp contrast from the initial announcement that contamination levels in beef were two to three times above legal limits. Despite the new results, officials stressed that it is of no risk to public health.

The agency's toxicologist Rob Evans said the initial announcement represented the level of 'indicator' PCBs found in the meat samples, not the dioxin itself.

Evans said several factors - including the lower level of fat in beef than in pork, consumers' preference for pork, and the better ability to track beef products to specific farms - indicate that people consumed far fewer dioxins from the beef than the pork before the problem was uncovered.

The joint Food Safety-Agriculture statement also said that the number of beef farms affected stood at 21, compared with a total of 120,000 cattle farms in Ireland.

The figure did not distinguish between beef farms from dairy farms, though the Irish food promotion agency Bord Bia said Ireland has 69,000 beef farms.