Authorities in Ireland are investigating the source of a contaminant found in animal feed.
Presence of marker polychlorinated biphenyl (PCB) in pork fat was detected during routine monitoring of the food chain for a range of contaminants, said the Department of Agriculture, Fisheries and Food.
PCB is a persistent organic pollutant that is mainly present in food due to industrial processes.
A small number of farms associated with the investigation have been placed under restriction, therefore animals from those farms will not enter the food chain unless laboratory tests proved them to be free of the contaminant, according to the Department.
A series of tests were being carried out in the department's Backweston, Co Kildare laboratory complex, while additional samples were sent to Britain for testing.
The Department was investigating the case with the Food Safety Authority of Ireland.