Sounds like some of it is still in there in crevices. Try using some kind of foaming disinfectant spray that will work itself into all the seam areas and sit there.

Our great refrigeration man/friend told me to always clean the fridge, and then wipe it down with vanilla. I like to open the door now.

Bleach it help spray it in the crevies and let it be with the door open. Then I would stuff a bunch of newspaper in it and close the door for about 24 hours.
Judy

Did you clean out the drip pan under the refrigerator? Did you remove all the drawers and clean in and under them? Do scrub the gaskets. I always think that parmesan cheese smells like vomit too--any in there?

Clean drip pan!! Many people don't realize that there is a drip pan. I don't know if it is just older models. I have a new side by side refridgerator and I haven't thought to look. But I haven't smelled anything either. Sounds like a job for DH. Anyhow, I learned the hard way about the drip pan. When I was a teenager still living at home with my parents, we were sitting at the kitchen table a got a good whiff of something rotten. Dear Mom had taken chicken out of the freezer to thaw in the bottom of fridge and had forgotten about it for a couple of days. Well, the water and the blood from the chicken leaked out of the bag into the drip pan. When she pulled the drip pan out......AAhhhhhh!!!! It was not a pretty sight or a pleasant smell. Now she checks it all the time.

One may have to disassemble the refrigerator to an extent in order to access the crevices where the old milk migrates. Even then it may take a half dozen bleach applications, or steam...
As the stink permeates the plastic, try sealing the surface with wax or polyurethane...

A relative who's a retired moving man told me to put in 1/2lb of ground coffee in an open bowl.. He said that is what they used to do when refer's they were moving were going to be unplugged for a while. He says it works better than baking soda.

Kitty litter absorbs odors. Try putting a pan in there....but of course the best cure is finding the source of the smell.....and cleaning it up.
Linda C

The hint I heard of is to soak a cotton ball with vanilla and leave it in the fridge or freezer.

The smell is caused by butyric acid (present in both sour milk and vomit). Did you try dissolving baking soda (or better still, washing soda) in water and washing every crevice of the fridge with it? Using any alkaline liquid will neutralize and wash out the acid.

I've heard that if you get deactivated charcoal like you would get at a pet store for fish, would work if you put that out in a bowl or something in the fridge. May take a day or two. Never had to try it, but thought I'd pass that along.