Buffalo mozzarella farms used to produce the PDO buffalo mozzarella DOP. On 19 April, China definitively removed the ban on mozzarella, originally activated on 28 March 2008, and tests held in December 2013 in Germany on behalf of four Italian consumer associations have highlighted dioxin and heavy metal levels at the lowest of five times at most permitted by law. To produce of cheese, a cheese maker requires of cow milk but only of buffalo milk. Producing 1 kg of butter requires of cow milk but only of buffalo milk. The steps required to produce buffalo mozzarella are: The digestive system of
Maytag Blue cheese but attempts to manufacture a similar cheese in the United States had thus far been unsuccessful. Difficulties encountered in making these types of cheeses produced a less than satisfactory product, and quality control would have been disastrous. "During the Second World War, [the] university patented the homogenisation of cheese milk and attempted to have charges levied on Danish cheese produced using homogenised milk. Their attempts failed, as it could be proved that this method had been introduced 20 years earlier in Denmark by Marius Boe." The problems encountered with producing Roquefort type cheeses in the United States for distribution were