Irish food authorities have expressed concern over reports that some French companies mixed sewage sludge with feed for poultry and pigs.
The Food Safety Authority said that it was not advising consumers, at this stage, to avoid French chicken and pork products, but was awaiting the outcome of an investigation by the EU Commission.
French authorities admitted at the weekend that some French animal-feed processing plants had used untreated sewage, residues from septic tanks and effluent from animal carcases in the preparation of feed for pigs and poultry.
EU food safety inspectors are due in France this week to investigate the reports, which were first aired on German television.
The admission could spark a new public health scare in Europe, following Belgium's dioxin crisis and Britain's BSE epidemic.
Officials of the French Ministry of the Economy admitted that they had uncovered four incidents, in late 1998 and early this year, in which animal sewage had found its way into three rendering plants [which reduce bone and offal to feed for chickens and pigs] and one gelatine manufacturer.
However, in a letter from the ministry to the EU Commission, the officials denied that human sewage, heavy metals or pesticides had entered the food chain, as reported on German television.
In the Republic, two major supermarket chains, Tesco and Superquinn, said that none of their fresh meat came from France, but they conceded that it was possible that some packaged consumer meals they stocked might contain French ingredients.
Both companies said that they were not withdrawing French products from sale, but would be keeping in contact with the FSA.
The authority said it was "concerned" that products derived from animals which had received the feed might have been exported to Ireland. "We will proceed on the basis of what the EU Commission informs us about this practice, if it took place, and if the results ended up in the food chain", a spokesman said.
A Department of Agriculture spokesman said that "minimal amounts" of French poultry and pork were imported into the Republic.
Germany's ARD television station alleged that companies in western and central France were mixing sludge from waste water plants and septic tanks into meat and bonemeal. According to the reports, some of the sludge would have contained human faeces.
A letter from the French Ministry of the Economy's Directorate-General of Competition, Consumer Affairs and the Repression of Fraud (DGCCRF) claimed that the "dysfunctions" it had found could have no ill-health effects and that "the elements incorporated [in the animal feed] had come from the waste of animals which were themselves fit for human consumption and not from water treatment plants outside the companies".
The EU Commission responded within hours to the DGCCRF letter, announcing that it would send veterinary officials to France this week to verify the French statement.
A French opposition politician, Mr Jean-Jacques Guillet, said that the tainted animal feed scandal - like the earlier crises over BSE and dioxin in poultry - demonstrated that border controls would have to be re-established within Europe.
He said that up to 30 tonnes of tainted animal feed was still being stored at Plouivy in Brittany. "I have the impression that the state is protecting the companies in question", he said. "They ought to be shut down."