use the arm and hammer baking soda to make a soupy paste to wash down all interior surfaces. remove all plastic bins and soak in baking soda water, a couple of boxes in a plastic trash can will make soaking easier. the plastic is just porous enough to absorb odors. it is always a good idea to keep a box of arm and hammer refrigerator baking soda in both the frig and the freezer, changing every month or so to keep them smelling fresh.
I had the same situation with a rental where the people left without notice and had the electric turned off, spoiled meat and rotted veggies, cloths pin nose time :o)
after cleaning and changing the baking soda every 2-3 days, the smell was gone in about 2 weeks