For many years Feta has been produced around the world as Greeks emigrated and took their favorite foods and recipes with them. It naturally followed that they would begin producing a cheese like Feta wherever they landed.
This included countries such as the US, France, Denmark, Germany, etc. and for the longest time they made and sold a cheese called 'Feta'.
Well, Greece found this to be too much competition for a cheese that they felt was their own and filed with the European Union for "Protected Status" and hence a very long court battle began in 1994 between those countries that still wanted to sell their cheese as 'Feta'.
This style of cheese was not unique to Greece because variations had been made for thousands of years in other regions such as Bulgaria, Turkey, etc. However in July 2002 the EU courts ruled in favor of Greece and gave them their "Protected Status" and thus excluding other producers in the European Union from using the name 'Feta'.
Bulgarian Feta simply does not exist. Bulgarians call their Bulgarian-style Feta 'Sirene', which means simply 'a cheese', it is still correct, in English, to call it 'Bulgarian Feta' even though it is a different subtype of Feta than the Greek one. The cheese has several different variations, depending on the milk used. Originally it was made with sheeps milk, but today much of it is made from cows milk.
You should take note that none of these Bulgarian packages of this style cheese pictured here contain the words 'Feta'. They simply say 'Bulgarian White Cheese' but not much at all has changed in this age old process. Note also that the packages above can be either sheep or cows milk.