Feta PDO has been protected since 2002, and Europe's top court reaffirmed that only Greece may call its cheese feta. Real feta is made from sheep's milk (with up to 30% goat), set and matured in brine in defined regions of mainland Greece and Lesbos.
The imitation is white cow's-milk ‘salad cheese’ from Denmark, Germany or beyond — legally barred from the name feta inside the EU. If it does not say PDO and Greece, it is not the real thing.