Milk is rich in vitamins and minerals and can provide the body with protein, beneficial fats and carbohydrates. However, spoiled milk does no good and can upset your stomach. Sometimes, milk that is still within its shelf life may go bad due to various reasons. There are many ways to tell if milk has gone bad, such as smelling the milk for an odor, observing the consistency and color of the milk, heating the milk, or seeing if it reacts with baking soda. [1]

Method 1 of 4:

Check the milk

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1

Smell the milk to see if there is any peculiar smell. Smell is one way to tell whether milk has gone bad, and it should be the easiest way. Fresh milk has almost no smell, while the smell of spoiled milk is unpleasant. If the smell of milk makes you subconsciously frown, it's probably spoiled. [2]

Some milk looks normal, but if it smells wrong, it’s best not to drink it.

If you have trouble telling whether the milk has an odor, you can find someone else to smell it, or use other methods to check whether the milk has gone bad.

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2

Observe the consistency of the milk to see if there are any lumps. Fresh milk is generally thinner and will pour smoothly. The consistency of milk depends on its fat content. Cream and whole milk are thicker than skim milk, but they also pour smoothly. [3]

If there are lumps in the milk, it means it has gone bad. You'll want to give the milk a shake to see if there are any lumps in it, as lumps will usually sink to the bottom of the container.

You can also look inside the milk container. If there are solids left in the container, the milk may have gone bad.

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3

Observe whether the color of the milk turns yellow or dark. Pour the milk into a clear glass, hold it up to the light and observe. Unspoiled milk will appear clean white, while spoiled milk will appear dark yellow. [4]

If you can't see the color of the milk, place a piece of white paper behind or next to the glass and compare the colors. If the milk is yellow in color, it has probably gone bad.

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4

See if the milk has been exposed to room temperature. To keep milk fresh, it must be refrigerated. Milk can easily spoil if it is exposed to room temperature for an extended period of time, regardless of whether it is actually expired. If a bottle of milk has been left out of the refrigerator for more than an hour, it has probably gone bad. [5]

If you live with family or roommates, it may be difficult to tell if milk has been left outside. It's best to ask them at this point to determine the situation.

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5

Make sure the milk is no more than 7 days old. If stored properly, milk can last up to 7 days longer than the shelf life stated on the box. However, if it's been more than 7 days and the milk has been left out of the refrigerator, it's likely that it has gone bad. [6]

The shelf life of milk depends on the fat and lactose content of the milk. Expired whole milk can only be consumed for another 5 days, and expired sugar-free or skimmed milk can be consumed for another 10 days.

If the milk is more than a week old, you should throw it away even if it looks and smells fine.