Around 700,000 eggs from Dutch and Belgian farms implicated in a contamination scare have been distributed to Britain, rather than the 21,000 first estimated, the Food Standards Agency (FSA) has said.

The insecticide Fipronil, found in the eggs, can be harmful to humans if consumed in large doses.

Egg-containing products including salads, quiches and sandwiches have been recalled from Sainsbury’s, Waitrose, Asda and Morrisons, although the FSA said some of the recalled products will have already been consumed.

Although the number of affected eggs which have entered the country is 33 times higher than was originally estimated, the FSA stressed there is no need for panic.

FSA chairwoman Heather Hancock said: “I’m confident that acting quickly is the right thing to do.

“The number of eggs involved is small in proportion to the number of eggs we eat, and it is very unlikely that there is a risk to public health.

“Based on the available evidence there is no need for people to change the way they consume or cook eggs. However, Fipronil is not legally allowed for use near food-producing animals and it shouldn’t be there.”

The FSA also released a statement following an investigation into the problem, in which it said that Fipronil is unauthorised for use near food-producing animals in the EU.

Eggs are destroyed at a chicken farm in Nadrin, Houffalize (AFP/Getty Images)

Fresh eggs are not believed to be affected, but Aldi and Lidl stores in Germany, along with Dutch supermarkets, have already taken millions of eggs off their shelves.

Aldi said it was a “purely precautionary” measure.

The scare began in the Netherlands and Belgium and it is thought that disinfectant used in products on chicken farms is at fault.

Belgian authorities admitted that a farm alerted them to possible contamination in June – several weeks before the scare became public knowledge – but they thought it was an isolated case.

Britain produces 85 per cent of the eggs it consumes but still imports almost two billion annually, the FSA added.

Reported adverse effects from consumption of Fipronil include sweating, nausea, vomiting, head and stomach pain, dizziness and seizures, according to the US National Pesticide Information Centre.

Approximately 180 Dutch farms, including egg farms, are believed to have used a product containing Fipronil to treat red mite in poultry houses.

Fipronil is classed by the World Health Organisation as a Class II moderately hazardous pesticide.

The affected products are processed foods in which eggs are one of the ingredients – mainly sandwich fillings and other chilled foods.

Many of the eggs involved were mixed with other eggs which have not come from affected farms so Fipronil residues will be highly diluted, according to the FSA.

“While in some European countries eggs containing Fipronil residues have been sold as fresh eggs, in the UK this is not the case,” it said.

“It is likely that the number of eggs that have come to the UK is closer to 700,000 than the 21,000 we previously believed had been imported.

“However, as this represents 0.007 per cent of the eggs we consume in the UK every year, it remains the case that it is very unlikely that there is any risk to public health from consuming these foods.”

How Brexit affected Britain's favourite foods from Weetabix to Marmite Show all 8 1 /8 How Brexit affected Britain's favourite foods from Weetabix to Marmite How Brexit affected Britain's favourite foods from Weetabix to Marmite Weetabix Chief executive of Weetabix Giles Turrell has warned that the price of one of the nation’s favourite breakfast are likely to go up this year by low-single digits in percentage terms. Reuters How Brexit affected Britain's favourite foods from Weetabix to Marmite Nescafé The cost of a 100g jar of Nescafé Original at Sainsbury’s has gone up 40p from £2.75 to £3.15 – a 14 per cent rise—since the Brexit vote. PA How Brexit affected Britain's favourite foods from Weetabix to Marmite Freddo When contacted by The Independent this month, a Mondelez spokesperson declined to discuss specific brands but confirmed that there would be "selective" price increases across its range despite the American multi-national confectionery giant reporting profits of $548m (£450m) in its last three-month financial period. Mondelez, which bought Cadbury in 2010, said rising commodity costs combined with the slump in the value of the pound had made its products more expensive to make. Cadbury How Brexit affected Britain's favourite foods from Weetabix to Marmite Mr Kipling cakes Premier Foods, the maker of Mr Kipling and Bisto gravy, said that it was considering price rises on a case-by-case basis Reuters How Brexit affected Britain's favourite foods from Weetabix to Marmite Walkers Crisps Walkers, owned by US giant PepsiCo, said "the weakened value of the pound" is affecting the import cost of some of its materials. A Walkers spokesman told the Press Association that a 32g standard bag was set to increase from 50p to 55p, and the larger grab bag from 75p to 80p. Getty How Brexit affected Britain's favourite foods from Weetabix to Marmite Marmite Tesco removed Marmite and other Unilever household brand from its website last October, after the manufacturer tried to raise its prices by about 10 per cent owing to sterling’s slump. Tesco and Unilever resolved their argument, but the price of Marmite has increased in UK supermarkets with the grocer reporting a 250g jar of Marmite will now cost Morrisons’ customers £2.64 - an increase of 12.5 per cent. Rex How Brexit affected Britain's favourite foods from Weetabix to Marmite Toblerone Toblerone came under fire in November after it increased the space between the distinctive triangles of its bars. Mondelez International, the company which makes the product, said the change was made due to price rises in recent months. Pixabay How Brexit affected Britain's favourite foods from Weetabix to Marmite Maltesers Maltesers, billed as the “lighter way to enjoy chocolate”, have also shrunk in size. Mars, which owns the brand, has reduced its pouch weight by 15 per cent. Mars said rising costs mean it had to make the unenviable decision between increasing its prices or reducing the weight of its Malteser packs. iStockphoto

The statement added: “We are reminding food businesses of their legal responsibilities which include informing the FSA or FSS and relevant local authorities immediately if they have any reason to believe that a food which they have imported, produced, processed, or distributed does not comply with food safety requirements.”

In spite of the reassurances offered by the food industry, some experts predicted the problem could escalate.

Professor Chris Elliott, chair if food safety at Queen’s University Belfast, said: “The Fipronil scandal continues to grow – more affected farms, flocks and indeed countries. I predict more revelations are still to come. There is a growing impact in the UK despite no evidence of any wrongdoing in the UK poultry industry.”

Eggs from a supermarket in London, Britain (EPA)

British egg processors accused the big supermarkets of “double standards” over their egg-buying policies.

Ian Jones, chairman of British Lion Egg Processors, said: “The major retailers are operating to double standards when it comes to eggs. All of them stock British Lion shell eggs but they use imported eggs in many of their other foods containing eggs.”

The organisation stressed the need for consumers and food producers to look for both British Lion eggs and egg products.

Mr Jones continued: “This is just the latest of a number of food safety issues connected to eggs produced outside of the UK in recent years.

“As we approach Brexit, shoppers are growing increasingly concerned about the ingredients used in manufactured food and now more than ever want and deserve transparency on food packaging.”

Recalled products are listed below.

Sainsbury’s Ham and Egg Salad – 240g (Use by August 9-14)

Sainsbury’s Potato and Egg Salad – 300g (Use by August 9-14)

Morrison’s Potato and Egg Salad – 250g (Use by August 13)

Morrisons Egg and Cress Sandwich – Sold in Morrisons Cafe only (Use by August 11)

Morrisons Cafe Sandwich Selection – Sold in Morrisons Cafe only (Use by August 11)

​Essential Waitrose free range egg mayonnaise filler – 240g (Use by August 16)

Essential Waitrose free range reduced fat egg mayonnaise filler – 170g (Use by August 14)

Essential Waitrose free range egg and bacon filler – 170g (Use by August 14)

Asda Baby potato and free range egg salad (Use by August 9-14)

Asda Spinach and free range egg snack pot (Use by August 9-14)