fresh yeast supplier

I have been baking bread for many years, first with a bread machine, then with the machine used to do the kneading, and now I knead the dough from scratch.  However I am unable to find a supply of fresh, the type that comes in a block like tofu does.  I have seen it used in England recently, but am unable to find a supplier in or near Toronto in Canada.  Anybody can give me tips on finding a supplier of Fresh Yeast, if it is organic it would be even better.  Armin