The news comes after it emerged that around 700,000 eggs implicated in the egg contamination scare have been distributed to Britain and may have already been eaten by consumers.
While 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."
Millions of eggs have been pulled from supermarket shelves in Germany as well as Belgium and the Netherlands.
Supermarket chains Albert Heijn, Colruyt and Delhaize have preventively removed eggs from their Belgian stores after a slightly increased concentration of toxic fipronil was discovered in eggs originating from a company in the Netherlands. The three chains stress that these are precautionary measures, as there is no danger to public health.
The Dutch company Chickfriend, which is responsible for the contamination of hundreds of thousands of eggs with the anti-lice agent fipronil, was not licensed to use pesticides. The agent used is strictly prohibited for use in animals intended for the food chain, as it may cause mild kidney, liver or thyroid damage.
In the UK, meanwhile, the Food Standards Agency previously said a total of 21,000 eggs contaminated with a chemical called fipronil had gone from the Netherlands to the UK, but it has now substantially revised its estimate.
On Thursday, the Commission intervened, saying it "continues to follow the latest developments very closely."
A spokesperson said, "Public health and issues related to food safety are always considered a priority and are treated as such."
The Commission has activated the rapid alert system for food and feed (RASFF), a tool designed to swiftly exchange information between national authorities on health risks related to food and feed.
The spokesperson explained, "A member country of the network that identifies a health hazard informs the rest of the system's network on the product concerned and the measures taken to address the risk."
Measures include withholding, recalling, seizing or rejecting products.
The spokesperson said, "This rapid exchange of information allows all RASFF members to check in real time whether they are also affected and if urgent action is needed. The authorities of affected countries have the responsibility to take the necessary emergency measures, including giving direct information to the public, withdrawing products from the market, and making controls on the ground."
He went on: “Member states have the primary responsibility for conducting the investigations and taking the appropriate measures. The Commission has taken and continues to take all available measures to assist them in this task.”
In large quantities, fipronil, is considered to be "moderately hazardous" according to the World Health Organisation, and can have dangerous effect on people's kidneys, liver and thyroid glands.
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.
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.