Look at some of the posts in the Food and Nutrition Forum as well as looking at the lists on the site.
I wouldn't include processed meats as part of the diet. And the cooked chicken and fish (have never fed beef) should be a very occasional part of the diet.
How big is/are your turtle/s? As they get older, they need more vegetation in their diet. Dandelions, chicory, collards (sometimes) and aquatic plants are also good to include.
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-
Definetly NO PROCESSED MEATS! Please check out the 'What to feed your RES' and 'What not to feed your RES' lists at in the Feeding and Nutrition section.
The things that come to those who wait may be the things that were left by those who got there first - Steven Tyler