Is pasteurized cheese vegetarian

Pasteurization just means it has been heated to a point to destroy harmful bacteria. Cheese is made from milk, so it is an animal product, and therefore, is not vegan. Although there are 'artificial' cheeses that are made from hydrogenated oils (soybean, palm kernel, etc.), that are vegetarian. You just have to read the label to see what the ingredients are.

A: Most hard cheeses contain rennet which comes from a cows stomach and is not vegetarian. There are cheeses which have vegetable rennet, but they are not vegan.