well it doesn't matter they mold at the same rate unless one is covered. If his is for a paper write that bacteria can't live in dehydrated food or freeze-dryed food because there is no moisture and bacteria needs mousiture to live
White bread doesn't necessarily mold faster than whole wheat bread. (White bread is usually made from wheat.) It depends upon the formulations, the quality of the ingredients, the processing...
There is no way that anyone can tell you which will mold the fastest since we don't know all the variables, like moisture, the formulation of the bread, the quality of the ingredients or the...