How do I do a simple test to the milk to know it's not ultra pasteurized?

It will often have a layer of fat above the rest of the milk. However, for obvious health reasons I strongly suggest you drink pastorized milk, if your worried about lost nutrients it's not signifigant enough to matter (only about 2%-6% of the nutrients are lost, which is insubstantial, especially considering the milk is purged of harmful bacteria and parasites)