Belgium's agriculture minister said Wednesday that the Netherlands detected a potentially harmful insecticide in eggs in November last year, nine months before the pan-European scandal became public.
Minister Denis Ducarme told a Belgian parliamentary hearing on the crisis that the Belgian 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."
"There was in relation to that no official communication from the Netherlands," Ducarme said, adding he has been in contact with his colleagues in the neighbouring country for an explanation.
The scare has hit major egg exporter the Netherlands the hardest, where the scandal erupted on August 1 and the Dutch authorities ordered eggs pulled from supermarket shelves and urged shoppers to throw theirs away.
Dutch authorities have temporarily closed 138 poultry farms and may cull millions of chickens.
In addition to the Netherlands, supermarkets in Germany, Belgium, Sweden and Switzerland have since pulled millions of eggs from the shelves.
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.
Fipronil is commonly used in veterinary products to get rid of fleas, lice and ticks. It is banned from being used to treat animals destined for human consumption, such as chickens.
In large quantities, the insecticide is considered to be "moderately hazardous" according to the World Health Organization, and can have dangerous effects on people's kidneys, liver and thyroid glands.
Criminal probes for suspected fraud are under way in Belgium and the Netherlands.
© 2017 AFP