Contaminated eggs that were imported from Europe have been distributed in the UK, the Food Standards Agency says.
Millions of eggs were taken off shelves in Germany, the Netherlands, Belgium, Sweden and Switzerland after they were found to contain an insecticide called fipronil, which is used in veterinary products to treat things like fleas and ticks.
It is thought to have been used on chickens in Belgium and could be potentially dangerous to humans.
However, the FSA insists the risk to public health is very low and the number of eggs affected is extremely small.
“The number of eggs involved represents about 0.0001% of the eggs imported into the UK each year,” it said.
“Our risk assessment, based on all the information available, indicates that as part of a normal healthy diet this low level of potential exposure is unlikely to be a risk to public health and there is no need for consumers to be concerned.”
The FSA says it is urgently investigating and indications so far are that the eggs are no longer on sale.
It added that the UK has already taken action to prevent risks to the public by adding fipronil to its robust surveillance programme in UK farms.
Belgian officials said on Saturday they had kept the problem secret and failed to trigger the EU’s international food safety alert system, but said it was because of a fraud probe.
The country’s agriculture minister said he had ordered its food safety agency to make clear why it failed to notify neighbouring countries until 20 July, despite knowing about the contamination since June.
A criminal investigation is under way.
A Dutch farming organisation has said that several million hens may need to be culled at 150 companies in the country, with 300,000 having already been killed.
The World Health Organisation says fipronil is “moderately hazardous” and can affect people’s kidneys, liver and thyroids.
The FSA says 85% of eggs consumed in the UK are produced here.