Give it good wash out with either white vinegar in warm water or bicarbonate of soda. Then a good wash with clean water.
You can buy a little egg shaped thing that has stuff in it that absorbs nasty niffs in the fridge..
Bicarb of soda solution and wipe it out. Also stick a halved lemon in there, thats meant to absorb odours and it also does a good job if you zap a lemon in your microwave to get the odours out of there