Belgium accused the Netherlands on Wednesday of failing to inform it that eggs were tainted with insecticide despite knowing about the problem since last November, as Europe's latest food safety scandal deepened.
Newly appointed Agriculture Minister Denis Ducarme told a parliamentary hearing that Belgian's food safety agency obtained an internal Dutch document that "reports the observation of the presence of fipronil in Dutch eggs at the end of November 2016."
"When a country like the Netherlands, one of the world's biggest exporters of eggs, does not pass on this kind of information, that is a real problem," said Ducarme, adding he has demanded an explanation from his Dutch colleagues.
The Dutch food and goods watchdog NVWA rejected the claim.
"The allegations that we knew about fipronil in eggs in November 2016 are untrue," NVWA inspector-general Rob van Lint said in a statement.
However, he admitted his body received an "anonymous tip-off" in November 2016 that fipronil had indeed been used to clean chicken pens in order to combat red lice.
"At that time there was no indication of an acute danger to food safety. There was not a single indication that fipronil could also be present in eggs," van Lint said.
French Agriculture Minister Stephane Travert said he wanted "much more fruitful and rapid exchanges of information" with his EU partners over the scandal.
His ministry announced at the same time an investigation into the French egg industry to check for fipronil.
The European Commission, which oversees the 28-nation European Union's food safety alert system, refused to comment on if and when it was told about the reported Dutch finding.
The Belgian hearing was called in response to an admission by officials at the weekend that they too knew about fipronil in eggs back in June, but kept it secret for nearly two months because of a parallel criminal fraud investigation.
The insecticide scandal only became public on August 1 when authorities in the Netherlands ordered eggs pulled from supermarket shelves and urged shoppers to throw any they had away.
Contaminated eggs have since been discovered in Germany, Belgium, Sweden, Switzerland, Britain and France, with several supermarkets pulling millions of eggs off the shelves.
'Defrauders must be punished'
Fipronil is commonly used in veterinary products to get rid of fleas, lice and ticks but it is banned by the EU from being used to treat animals destined for human consumption, such as chickens.
In large quantities, the insecticide is considered by the World Health Organisation to be "moderately hazardous" and can have dangerous effects on people's kidneys, liver and thyroid glands.
The scandal has led to finger-pointing between Belgium, Germany and the Netherlands as they try to get to the bottom of how the scandal could happen.
Ducarme said that Dutch knowledge of the problem since November only emerged when the Belgian food safety agency "through certain contacts was transferred, by chance, internal information" from its Dutch counterpart.
If the Netherlands had notified Belgium sooner "our vigilance about fipronil would have been increased, greatly increased".
Germany has meanwhile demanded answers from both countries.
Criminal probes for suspected fraud are under way in Belgium and the Netherlands over the tainted eggs, but prosecutors in both countries have refused to give any details.
"The defrauders must be punished harshly by the courts because, in order to enrich themselves personally, they have not hesitated to risk the health of consumers," Ducarme said.
The problem is believed to stem from a substance used by a Dutch company, Chickfriend, that farmers in the Netherlands and Belgium say they hired to treat their chickens.
A lawyer for a Belgian company, Poultry-Vision, says the firm sold it to Chickfriend but has not said where it got the substance.
The French government says a Belgian company -- which it did not identify -- mixed fipronil with another, lawful, substance.