Further to my article on Parmesan not being suitable for Vegetarians, I wanted to clarify other cheeses.
There are many cheeses that are suitable for vegetarians, you just need to check the label when you are buying them from the cheese counter.
Traditionally cheese is made by using animal by products, namely the lining of a cows stomach. Vegetarian Cheese is made by using rennet from a fungal or bacterial source. Soft cheese too has its problems and many are not suitable for vegetarians.
Hard cheeses that are NOT suitable include Parmesan, Grana Padano and Gorgonzola. By law they contain the animal by product.
From the Vegetarian Society
Cheese is made by coagulating milk to produce curds (solids) and whey (liquid). The curds are separated from the whey so they can be processed and matured to produce a wide variety of cheeses. The coagulation of milk is achieved by the addition of rennet, the active ingredient of which is the enzyme chymosin (also known as rennin). Paneer, of Indian Origin, is one cheese which does not involve the use of rennet as heated milk is curdled with the addition of lemon juice or other acid food.
The traditional source of rennet is the stomach of slaughtered newly-born calves.
Vegetarian cheeses are manufactured using rennet from either fungal/bacterial sources or genetically modified micro-organisms.
Always check the label and when eating out always double check with your server that the cheese they are using, is labelled as suitable for vegetarians. It is a common mistake with restaurants, especially when it comes to Parmesan.