The Irish government said Saturday it was recalling all pork products made in the Republic of Ireland after the discovery of a toxic substance in slaughtered pigs.
The Food Safety Authority of Ireland (FSAI) advised consumers not to eat Irish pork and bacon products until it knew the extent of the contamination by dioxins, which have been linked to cancer.
It was not yet clear which countries would be affected beyond Ireland, but official figures for 2006 showed Britain was the biggest importer of Irish pigmeat, followed by Japan, Germany, Russia, France and the United States.
"The government today announced that laboratory results of animal feed and pork fat samples obtained this afternoon by the Food Safety Authority of Ireland confirmed the presence of dioxins," a government statement said.
"Consequently, the FSAI is requiring the food industry to recall from the market all Irish pork products produced from pigs slaughtered in Ireland."
FSAI spokesman Alan O'Reilly said the level of the dioxins found was 80 to 200 times the safe level.
Exposure to very high levels, such as during an industrial accident, has been associated with increased incidence of cancer, but officials said the risk to consumers posed by the current contamination was "extremely low".
The contamination is thought to have come from a feed mixture, and was identified at the end of November following routine testing. All pork products produced since September 1 have been recalled.
O'Reilly said a range of foods including sausages, bacon and pizza toppings should be destroyed, adding: "The whole idea is to try and limit the exposure of consumers to this form of chemical."
Dioxins are persistent chemical contaminants in the environment. They can be formed naturally, such as in forest fires, but are usually by-products of certain industrial combustion and chemical processes.
The recall is likely to hit Ireland's pig industry hard, at a time when the economy as a whole is in recession. About 5,000 people work in the sector, which is worth about 400 million euros (500 million dollars).
Padraig Walshe, president of the Irish Farmers' Association, said the situation was "an absolute disaster" for the country's pork producers.
"The Christmas market is the most important time of the year for the pig sector with a lot of people contemplating buying hams along with turkey for the Christmas market," he told the RTE state broadcaster.
But he said he supported the government's action, adding that he expected Irish pork products to be back on the market as early as next week.
Ireland's food minister Trevor Sargent said he was working to ensure this happened as soon as possible but said ministers had no choice but to act.
"Food safety and the consumer's interest have been the main priority behind this government action," he said.
Britain's Food Standards Agency said it was monitoring the situation, but said there was no cause for alarm.
"From the information that we have at this time we do not believe there will be a significant risk to UK consumers," a spokesman said.