Milky Explorer

It's been just over a month since I left a gallon of milk under my backseat for a week, half of which ended up in the carpet.  The smell is getting stronger each week and i'm not sure what to do.  I tried scrubbing, shampooing, and bleaching and I've got nothing.  I can't figure it out.  How is it possible that I shower once a month and never smell bad, yet I wish my carpet every day and it just smells worse.  This is more confusing than getting the straw into a Capri Sun for the time.