Dioxin contamination has led to recall of Irish pork products. Authorities found dioxin level in pig meat on a number of farms to be between 80 and 200 times more than the recognised safety limit.
The Food Safety Authority of Ireland (FSAI) has called for the destruction of all pig products already bought by consumers.
The recall involves retailers, the hospitality sector and the Irish pig processing sector and the FSAI advised people "as a precautionary measure not to consume Irish pork and bacon products at this time".
It said updates the extent of the risk from human consumption would also be made available.
Dioxins are complex organic compounds released into the atmosphere from fires and other forms of combustion. They are naturally occurring and accumulate in the fat of animal or in plant tissue.
They are mostly found in insignificant levels but a small number are highly toxic and can cause a range of ailments from cancer to skin diseases and damage to the reproductive and immune systems.
Consumption of dioxins above safe levels over a lifetime may result in an increased risk of cancer. The World Health Organisation and the European Unions' Scientific Committee for Food have determined the levels of exposure to dioxins which are safe.
The FSAI recall affects all products produced since September 1st and will have very severe repercussions for the State's pork industry which is worth close to half a billion euro annually. It comes at one of the sectors busiest times of the year and was dubbed "an absolute disaster" by farming groups.
The announcement was made at a joint press briefing held by the FSAI and the Departments of Health and Agriculture last night following a day of negotiations and discussions at the highest level.
The contamination first came to light last Monday but was only confirmed by Government officials yesterday afternoon.
Agriculture Minister Brendan Smith said an "intensive investigation" had been underway this week. He said 47 farms, including 38 beef farms, had been restricted because they were identified as having received possibly contaminated animal feed. There was only one feed supplier involved, he said.
"Full prohibition of animal movement from these herds is in place. We've outlined the actions that we're taking on recall of pork and bacon following the receipt of the laboratory results ealier [yesterday] evening.
"The issue of beef involvement is very different. Our assessment on the basis of advice from the Food Safety Authority of Ireland is that no further action at this stage other than what we have done in prohibiting movement off the farms is required.
"Testing is however taking place on a precautionary basis in line with our overall approach to this problem."
Earlier this week restrictions were placed on a number of pig farms after organic pollutants known as polychlorinated biphenyls (PCBs) which are linked to dioxins were detected in pork fat during routine monitoring.
Rod Evans, a spokesman for the FSAI told irishtimes.com that the health risks were likely to be "very small" and said a short period "of higher level exposure to the dioxins is unlikely to have any health consequences".
The Minister for Health, Mary Harney, said she and Ministers Smith, Sargent and Wallace had spent the day in discussions with experts.
"I think we've acted in a timely fashion given that the confirmation happened at 3.40 this afternoon from the laboratories in York in the UK," she said.
"From now on those products will be withdrawn from the market obviously here and internationally. We hope very quickly that non-contaminated pork products can be back on the market. We hope that that can happen as quickly as possible provided they operate to the highest possible standards as far as public health is concerned."
The president of the Irish Farmers' Aassociation Padraig Walshe said the recall was "an absolute disaster" at an "important time of the year for the pig sector".
Speaking on RTE television he said he expected "perfectly safe" pork from Irish producers to be on sale again by the middle of next week.
In recent years, there have been a number of dioxin contamination incidents of food worldwide.
In 1998 dioxin-contaminated citrus pulp from Brazil was used in feed for dairy animals in France and resulted in contaminated milk.
A year later in Belgium dioxin laden machine oil contaminated animal feed affecting poultry, eggs, red meat and milk which caused a major food crisis.
The pig farming industry is the fourth biggest sector in Irish agriculture and some 400 pigs farmers are operating in the sector.