Italian authorities sought to calm consumers on Wednesday after dioxins were found in the buffalo milk used to make Italy's famous mozzarella.

Last week high levels of dioxins, chemical contaminants, were found in samples of buffalo milk in the southern Campania region, so far 25 facilities in southern Italy have been temporarily closed.

The country's health ministry official, Gian Paolo Patta, said most of the products were, "absolutely not affected by the dioxin. We are going to precisely determine which farms provided milk outside cheese dairy standards."

Italian Foreign Minister Massimo D'Alema meanwhile said only nine out of the country's 132 producers had been detected with traces of dioxin, adding that the international alarm over mozzarella was "excessive and unfounded."

Experts warned that the production of one of Italy's best known exports is under threat with mozzarella sales plummeting by 40%. Last week, Japan and South Korea banned imports of the cheese.

The Italian mozzarella sector employs 20,000 people and produces over 46,000 tons of mozzarella a year.

The Russian newspaper Novye Izvestia said a number of restaurants in Moscow were carrying out safety checks.