Some products have been withdrawn from Sainsbury’s, Morrisons, Waitrose and Asda, according to Food Standards Agency.

About 700,000 eggs from Dutch farms implicated in a contamination scare have been distributed to Britain and some supermarket products have been withdrawn, the Food Standards Agency (FSA) has said.

The FSA said investigations into the Fipronil incident in Europe suggested it was “very unlikely” that the eggs posed a risk to public health, but the number of contaminated eggs estimated to have reached the UK is far higher than the 21,000 first estimated.

Products withdrawn include salads from Sainsbury’s, Morrisons and Asda plus sandwiches from Waitrose and Morrisons.

The FSA added that some of the products made from these eggs will have had a short shelf life and will have already been consumed, but some were still within the expiry date and were being withdrawn by the businesses involved.

On Monday the European commission said that British food safety authorities were alerted over the weekend that eggs imported from Germany could be dangerous. Officials in France, Sweden and Switzerland were also informed of a risk to consumers.

A spokeswoman for the commission, Anna-Kaisa Itkonen, said it was “up to the Swedes, Swiss, French and to the UK national authorities to check”.

The FSA had originally said British food safety inspectors were trying to trace 21,000 eggs imported from affected farms in the Netherlands between March and June.

Prof Chris Elliott, director of the Institute for Global Food Security at Queen’s University Belfast, praised the watchdog’s quick response to the crisis but warned it could be difficult to track down the eggs.

Fipronil is an insecticide and is a common ingredient in veterinary products for getting rid of fleas, lice and ticks. It is banned from being used to treat animals destined for human consumption.

According to the World Health Organisation, the toxic substance can damage the liver, thyroid glands and kidneys if ingested in large amounts over time.