Ron:
Clean it out with soap and water, rinse. Then wipe down the entire interior - including every shelf, butter compartment door, everything - with a half cup of liquid chlorine bleach in a gallon of water. Rinse, repeat. This will kill the mold spores remaining.
Now leave the doors open for a couple of days to let the bleach smell dissipate. If it still lingers after that, a final wipedown with a solution of white vinegar and water should get rid of it.
It is very important not to turn the fridge on until you've gotten rid of the mold. If you turn it on, mold spores will enter the fridge's air-handling system. When that happens, it's an absolute bastard to correct.