I think your making a mistake tossing the fridge/s. Hose it out, remove all the interior ducts, hose them out. Use bleach with a bit of detergent. Once cleaned and detailed storing the unit with the doors open for a few days worked wonders. If you can get it into the sunlight it helps.

If that doesn't do it. or you want to speed the process, use a mix of hydrogen peroxide, baking soda, and a small bit of dish soap. Wash, let dry ... wash, let dry.

We also had luck with oxygen based laundry bleaches.

In both cases once the organic soils are removed the scent molecules are broken down and dissipated by oxidation. Which is why the hydrogen peroxide works.

I'm down here in hurricane country and used to work at an apartment complex where people would move away and have the electricity disconnected with a the fridge full of food. A fridge full of vegetables and dairy product and a freezer full of fish and pork left in summer in Florida temperatures for two months is pretty bad. people downwind of us carrying it still full out of the apartment were puking. But getting the smell out of the apartments was always harder than getting it out of the refrigerators. Drywall and carpeting soak up smells.

Cleaning out the refrigerators in such condition is a nasty, time consuming job. But, as long as the interior plastic liners were intact, if rotting food gets into the insulation it is a bigger problem, we never tossed any of the refrigerators out.

Bottom line is that even a new refrigerator goes for something north of $600 so an afternoon or two of suffering is justified. Mid-line refrigerators go for closer to $1000 and high-end units are up from there.

Worse case we use to prop the doors open on a concrete slab downwind of the complex, get on rain gear and boots, use a shovel to scoop out the bulk crud, and jet the worse of it out with a hose from fifteen feet away and up wind. Then close with the issue with rubber gloves and a brush. The first half-hour is the worse. By mid morning it looked clean and the smell was tolerable. After that it was peroxide or oxygen bleach applied with a pump-up sprayer a couple of times and storage, with the door blocked open, in a hot open-air garage for a few days.

Never had one we could get right.

It is a question of what you are willing to do for $1000.

Of course, if the insurance company is going to give you a new one that changes the calculation a bit.