Ok looking at the Wiki, I don't think these items spoil:
Fish Fillet
Flour
Grains
Large Piece of Raw Meat
Piece of Raw Meat
Small Piece of Raw Meat

Does raw meat even spoil? Food spoilage might only affect cooked foods or foods that doesn't require cooking.
I'll do some experimenting.

Raw meats (S, M, L) is not working, just disappear. smoked or cooked works fine. i think you just need to add raw meat.

Try adding a piece of food to it yourself. So just drop a berry in there.

it's not working. my food just disappeared like in toilet. I didn't receive spoiled food :c

Thanks Finch, yea I find it's really helpful.
My villagers loot all kinds of basic/low level crap food, so when they come back, they dump all that in this chest, it's gone within 10 seconds and they only carry/eat the foods I want them to eat (namely the berry jam/fine stews etc).

It's small additions like this which make village life more pleasant. I get a lot of food from bandit raids and what won't fit in the food storage I throw in the barn to spoil overtime. It does what it says on the box (spoils in seconds) and my compost bin loves it.