"The two basic ingredients of Bengali sweets are sugar and milk. The milk is thickened either by
boiling it down to make a thick liquid called khoa, or by curdling it with lemon juice or yogurt to
produce curds, called channa. There is some debate as to whether the latter was a traditional
technique or a Portuguese contribution. Portuguese cheesemakers in Bengal used to produce
curds by breaking milk with acidic materials. One of their products was a salted smoked cheese
called Bandel Cheese, which is still made and sold in Calcutta"
This an excerpt from a lovely paper outlining the the Portuguese influence on Bengali cuisine presented at the Oxford Symposium on Food and Cookery [which you can read here].
I also might add that I love Bandel cheese and make it a point to get some discs wheneuver I am back in Calcutta. If you're in the city, make sure to drop by the dairy section of New Market and have some.