I'm only on page 2 of this thread and don't know if this has been mentioned yet............
On Nancy Grace today, she had on a woman dog handler with Homeland Security, showing how cadaver dogs work. The woman said that the day before she had hidden cadaver scent on the set in the studio where she was being filmed. She took the dog off it's lead and gave it a signal. The dog immediately ran to a sofa that had a lot of pillows on it and jumped up on the sofa and sat by one particular pillow. The dog handler went to the dog and gave it it's reward - a dog toy. Behind the pillow was a jar holding a tightly wrapped sheet that had covered a cadaver.
Nancy Grace asked the handler.........."dogs can smell the sent of a cadaver even if the scent in in a sealed jar?" The dog handler said, "yes, a dog's sense of smell is so strong, that even in a sealed container the dog can smell the scent." Nancy asked a lot of good questions. One was, "Can a cadaver dog tell the difference between a human cadaver and an animal carcass." The handler assured Nancy that the dogs are trained specifically for HUMAN cadavers, not animals and will alert only on human remains.
The dog handler also said that dogs trained for cadavers won't alert on drugs, bombs, etc. - that drug sniffing and bomb sniffing dogs are trained for that particular task only, and won't alert on cadavers.
It was very clear that a cadaver dog is NOT going to alert on old pizza left in a car.