Saw these two cheddar cheeses for the first time today at a local grocery store (QFC for those in Seattle). I have never heard of the concept of either....what exactly makes a cheese vegetarian or kosher?

The packaging didn't seem to indicate anything special. It's probably a case of those who are looking for it know what makes it unique

Quite a lot of supermarket Chedder in the UK is now vegetarian.

You can google this to learn more, but, my understanding of this is that the traditional way to produce cheese is to use rennet, a substance produced by young cows which helps them digest milk. As calves' stomachs are used, cheese made this way cannot be considered vegetarian.

I imagine that it's easier to standardise and produce large quantities of vegetable/fungal rennet type enzymes than use calf stomach in modern style mega-production so vegetarian cheese (in the UK at least) has become easier and easier to find in the last couple of decades, or perhaps sales do better when a manufacturer can show the little green vegetarian sign on the packaging. I couldn't say.

Kosher - I believe meat and milk can't be mixed in a kosher diet, so cheese made with meat/meat enzymes would be a no no. Milk curdled by vegetable rennet is probably fine.

LapLap, you are right on about that. At Whole Foods or TJs, on a lot of the cheese, they will specify where the enzymes are sourced from (microbial, etc..). There is no taste difference at all, in my opinion.

My first thought was that you were talking about soy cheese. I have seen soy cheese in the vegetarian or health food specialty shops. I have never noticed vegetarian real cheese but maybe they don't have that in Australia yet.