In addition to examining your dog's food, is your dog crated a lot or rescued from a situation where they were crated a lot? Dogs in these situations will sometimes eat their own feces to keep their space clean and/or out of boredom.
You can also try adding a teaspoon or two of pineapple of pumpkin to their food. Apparently it tastes good the first time, but not good the second time. There are also a couple of different sprays that pet stores sell that give the poo a bad odor.
She refuses to eat dry dog food and will only eat expensive wet food. Here in Australia ther is a brand called VIP puppy food, she loves the chicken and turkey flavour. We have had her since she was about 6-7 weeks old. She only gets carried around sometimes by my daughter like Paris Hilton carries her dog. She uses a litter tray as a toilet as she is an indoor dog,and will take some poo out of the litter tray and put it in her bed. I try to make a habit of cleaning up when she is noy around as I read somewhere dogs can mimic you trying to help clean up.
There was an episode of The Dog Whisperer in which Cesar worked with a dog that ate her poo. He taught her to trade her poo for bites of banana. He said that sometimes eating poo is caused by a deficiency in potassium which bananas has lots of. Also the dog preferred the banana and the attention she got when she ignored her poo. Its worth a try.