Hi Mahon;
Welcome to the forum? I'm not sure what turf means, but it sounds like you threw it out.
You are not providing much information; such as did you every make this batch of jerky in the past? Did you taste it? Was the texture of the jerky bendable, or more on the brittle side? Whatelse was used in the marinade - such as did you have soy sauce in the marinade?
Most jerkys look black or close to it, depending on what is in the marinade. If you never made this batch of jerky in the past, the dark color may come from the Dr. Pepper. Though I've never used Dr. Pepper in my marinade, when I use soy sauce, my jerky comes out a deep mahogany, which can often look black.