By Katie Morley
Around 700,000 eggs implicated in a contamination scare have been distributed to Britain and may have already been eaten by consumers, it has emerged.
The Food Standards Agency previously said a total of 21,000 eggs contaminated with a chemical called fipronil had come from the Netherlands to the UK, but today substantially revised its estimate.
In large quantities, fipronil, is considered to be "moderately hazardous" according to the World Health Organisation, and can have dangerous affects on people's kidneys, liver and thyroid glands.
Asda, Morrisons, Sainsbury's and Waitrose are all urgently withdrawing millions of fresh salads, sandwiches and fillers which contain the infected eggs.
Fresh eggs are largely unaffected, with contaminated eggs instead present in processed foods in which they are one ingredient among many others, mostly used in sandwich fillings or other chilled foods.
The eggs were imported to the UK between March and June, the Food Standards Agency said.
A spokesman admitted that the infected products would no longer be within their expiry date, meaning they would have already been eaten.
The FSA insisted there was "unlikely" to be a risk to public health but admitted it was still investigating the distribution of the eggs.
An FSA spokesman said: "The decision to withdraw these products is not due to food safety concerns, but is based on the fact that Fipronil is not authorised for use in food producing animals. The Food Standards Agency and Food Standards Scotland are committed to ensuring that food is safe, and that UK consumers have food they can trust."
Now Dutch investigators have detained two men suspected of being involved in the illegal use of pesticide at poultry farms that sparked a massive food safety scare in several countries.
Dutch prosecutors said in a statement that the two men detained during a series of raids are directors of a company that allegedly used Fipronil in egg farms.
Though no one has been reported as falling sick, prosecutors said there is evidence that public health has been threatened by "the delivery or application of the biocide Fipronil in poultry houses in the egg sector."
The raids in the Netherlands were carried out as part of a joint action with Belgian authorities.
Millions of eggs have been pulled from supermarket shelves in Germany as well as Belgium and the Netherlands.
Aldi and Lidl stores in Germany have already taken millions of eggs off shelves amid fears they are tainted with traces of the pesticide Fipronil.
A spokesman at the British Egg Industry Council said: "All major UK retailers stock British Lion shell eggs and tests have shown that there is no risk from British eggs.
"Most eggs imported into the UK are used by caterers, or are processed for food manufacturers and other businesses for use in products with eggs as an ingredient.
"Food manufacturers, retailers and caterers using processed egg should look for egg products produced within the British Lion Egg Products scheme. This guarantees that they will have been made using British Lion eggs, produced to the highest standards of food safety."
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.
"This is just the latest of a number of food safety issues connected to eggs produced outside of the UK in recent years. Consumers clearly want retailers and food manufacturers to use good quality British ingredients that are produced to high standards of food safety, but in some prepared foods this is not the case.
What is Fipronil
Fipronil is an extremely widely used pesticide. A slow poison that acts on insects' nerves and muscles, it is far less toxic to mammals due to chemical differences in the nervous system. For this reason it is particularly common as an anti-flea treatment on household pets.
It is not authorised for use as a veterinary medicine or pesticide around food producing animals in Europe. In some countries, such as the Netherlands, it is permitted to use Fipronil to protect the roots of farm plants, as long as there are no animals present.
Fipronil is classed as "moderately hazardous" to humans by the World Health Organisation. Symptoms of acute Fipronil consumption can include sweating, nausea, vomiting, headache, abdominal pain, dizziness, agitation and seizures. These symptoms will generally disappear, although they can also be managed through clinical treatment, generally with benzodiazepines.
As an ecological contaminant, Fipronil is one of the main chemical causes blamed for Colony Collapse Disorder in bees. It is also highly toxic to fish, aquatic invertebrates, upland game birds and rabbits as well as many species of insect.