Unopened pasteurized milk sitting outside the fridge for 12 hours. It's now in the fridge and not yet open. To be on the safe side, will not be consumed as normal. Can something be made out of it? It's not a matter of cost - just of principle.

The question is not at all a duplicate of How long does it take for milk to spoil unrefrigerated? because it's about a way to make use of milk that won't be used in a normal way due to potential spoiling. Are there not dairy products that make use of fermentation? Is that not "spoiling"?


3 Answers 3


What is "spoiled milk"?

"spoiled" milk is not a thing, that needs to be avoided, in most cases. As long as it doesn't have any mold growing or something, it most likely just started fermenting in the warm temperatures outside the fridge. However, it is perfectly possible that your milk didn't even start to ferment after 12 hours, depending on the room temperatures where you are. In case it has started fermenting it should smell sour and contain clumps. If it smells normal and had a normal consistency you can use it as normal.

What to do with fermented/soured milk?

Milk that has started to ferment is called soured milk. It is used in many places in Europe, though most commonly in eastern Europe as far as i know, but probably in many places around the world, too.

I'm from Germany and my mom always used sour milk wherever you would use buttermilk. It has a similar tanginess and texture, but of course contains a bit more fat. You could use it in cakes and pancakes, but also in brines or marinades, as well in a base for breadcrumb coatings or similar things. Speaking as a german, there are a variety of mostly forgotten regional dishes where soured milk is the main ingredient, mostly desserts and soups.

Some people even drink it as is. I've heard, before lactose free milk was a thing, many lactose intolerant people prefered soured milk over normal milk, because of its lower lactose content due to fermentation.


Make cheese!

You'll be heating the milk, which should kill any harmful bacteria, but essentially you need soured milk to make cheese anyway.

There are countless recipes online, but ricotta is the easiest (in my opinion) cheese to make at home.

Source: Food52


The typical use in our family for spoiled/soured milk was to use it in baked goods. Typically, it got saved for the weekend when my mom would make pancakes or waffles with it. (It was put back into the fridge with a 'Mr. Yuk' style face drawn on the side of it as a warning not to open it)

... but we weren't typically dealing with a whole container, maybe a quart at most at a time. Although you could make up a larger batch and freeze them for some other day.

If the milk got the point where it started to make cheese on its own (ie, it started to separate and get chunky), we disposed of it.

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