The Department of Agriculture confirmed last night it had traced contaminated eggs from recent salmonella outbreaks to three farms in Northern Ireland.
A Department spokesman said: "We have been able to move quickly and pinpoint the source of infected eggs responsible for food poisoning in Donegal and Wicklow. Our investigations show that egg producers and packers in the South were not involved."
Having found the source, he said it was now a matter for the appropriate authorities in the North to deal with the matter and put in place measures which might be necessary to protect the public.
As two more people were hospitalised due to salmonella in Co Wicklow, the Food Safety Authority (FSA) has warned the Irish egg industry, egg suppliers and supermarkets that they must ensure sufficient safeguards were in place to minimise the risk to consumers.
The Eastern Health Board confirmed that five people were now in hospital due to gastroenteritis linked to a Chinese restaurant which has closed voluntarily in Bray, Co Wicklow. Their condition was described as serious but "not life-threatening".
Dr Pat Wall, the FSA chief executive, said a picture was emerging from the four recent outbreaks which had affected more than 100 people, including 13 who were hospitalised. This suggested that the infection was arising from contaminated eggs being used mainly in restaurants and hotels, rather than in homes.
While Irish poultry meat and egg producers were market leaders in Europe, he suggested that sufficient safeguards might not be in place to eliminate "a small subset of inferior eggs" getting on to the Irish market.
He said outbreaks were likely in the event of undercooking salmonella-infected eggs or using them raw. Poor hygiene could also be a factor "but eggs should not be contaminated in the first place".
The FSA believed that consumers had been adequately alerted to the risk if such eggs were not cooked thoroughly. "The onus is on the egg industry, including suppliers, retailers and those in the catering business, to show everything is in order. Responsibility rests with them. They should know where they are getting their poultry, and be getting eggs from flocks screened for salmonella."
He said supermarkets, which have huge buying power in Irish food retailing, should be specifying when ordering that they want eggs from salmonella-free sources.
It was not always easy to trace eggs as in some cases all that was identified on products was egg packagers, not the flock from which they came. Yet some suppliers stamped their eggs individually, a sign of the high standard which was being achieved in the Republic.
Mr Liam Butler, of the Irish Egg Association, which represents egg-packing interests, said most of its members had special measures in place to ensure product was coming from salmonella-free stocks.
He said after close consultation with the food body, An Bord Bia, the association was on the point of finalising a quality assurance scheme. This would make high standards obligatory for those who wished to be registered in it and ensure salmonella control and product traceability.
He added that the recent slaughter of hens on a Co Monaghan farm was completely unrelated. This was the result of a routine test by the Department because there was a very high health status. The eggs were sent for pasteurisation and there was no risk to consumers.
Mr Butler said at the moment there were voluntary controls but in September a quality assurance scheme would be introduced for table eggs.
Meanwhile, the Eastern Health Board has said the total number of people affected by the Co Wicklow outbreak had risen to 66.
