Twenty Italian buffalo farms have tested positive for raised dioxin levels, the country's health minister said Friday, as the country began recalling tainted mozzarella from the market.
Nevertheless, Singapore announced it was joining Japan and South Korea in banning Italian mozzarella sales as a precautionary measure.
The southeast Asian city state's Agri-Food and Veterinary Authority said the ban was a precautionary measure until laboratory tests could "determine if they have been contaminated with dioxin".
Rome's decision to withdraw the famous cheese from sale led the European Union to conclude that no action to protect consumers was necessary, and France quickly reversed a decision to pull imports of the cheese from the shelves.
The scare began last week when samples of mozzarella from the Naples region, which is made from buffalo milk, were found to have raised dioxin levels.
A total of 83 buffalo farms were quarantined. Of those 20 were found to have higher than approved dioxin levels, Under-Secretary of State for Health Gian Paolo Patta told the ANSA newsagency.
A dozen other farms have had quarantine restrictions lifted after testing negative, he added, without giving details for the remainder.
Italy's Foreign Minister Massimo D'Alema said Rome would "take the steps agreed with the European Union to withdraw products that do not comply with standards and renew assurances to Italian and foreign consumers".
The EU commission said it was "satisfied" with the move. "There is no reason at this stage to take further action at the EU level," spokeswoman Nina Papadoulaki told journalists in Brussels.
Initially on Friday, the French government announced it would impound shipments of mozzarella from Campania, but rapidly reversed that decision after Rome's announcement that it was withdrawing the cheese from sale.
Dioxin lead to an increased risk of cancer, and environmentalists link the cases to the long-running saga of rubbish disposal in and around Naples, which saw thousands of tonnes of garbage left undealt with at the end of last year.
The Italian government has said that no tainted mozzarella has been exported, and Agriculture Minister Paolo De Castro insisted at a news conference on Thursday that "there is no health problem".
He also rejected any link between the mozzarella contamination and the waste disposal crisis.
The refuse problem has gripped the region since 1994, where a lack of incinerators has led to overflowing landfill tips, which the local mafia is alleged to use for the illegal dumping of toxic waste.
Patta said farms that tested positive would remain quarantined for between 90 and 120 days, to allow the buffalo herds to eliminate the toxin.
"The inquiry will all-encompassing and noone will be excluded," Patta added.
Italy produces 33,000 tonnes of mozzarella per year, some 80 percent of it in Campania, where a quarter of a million buffalo are farmed to produce milk for the product.
Buffalo milk mozzarella is a soft cheese served with tomatoes and basil in a Neapolitan speciality, the Caprese salad.