Like the TK case I have heard of things like pepper being spread to deter dogs picking up the smells but I am not sure of how effective it can be. My guess is it may have some effects on the dogs but is probably not a foolproof way to deter all dogs from picking up some scents some of the times.
I have also heard of perps using like Fox Urine or other varment's urine which you can readily buy at hunting stores. The perps think it can deter cadaver dogs from picking up a body scent. The urines are called "masking scents" and are typically used to mask a hunters own scent when they are trying to hunt like deer or other game.
I have personally used Fox urine before when hunting and it does work to give off a strong odor. I had a fox literally come to my deer stand when I had fox urine on. The idea was to keep deer from smelling me and I was not trying to attract a fox or hide a body. LOL