How to know if milk is spoiled? (5 common ways)

In this brief article, we are going to answer the question “how to know if milk is spoiled”, discuss the different methods of identifying spoiled milk and the potential health effects of drinking spoiled milk.

How to know if milk is spoiled?

There are several signs that milk has gone bad, and they can be identified by its appearance, smell, texture, color and taste. Here are some common indicators:

Important: consuming spoiled milk can lead to food poisoning and other health issues, be careful! (1-3).

  1. Appearance: Fresh milk is usually smooth and uniform in color, with a slightly creamy texture. When milk goes bad, it may become chunky, curdled, or thick, and may also have a yellowish or bluish tint.
  2. Smell: The smell of sour milk is quite distinctive, and it is usually described as a sour, unpleasant and rancid odor. If you notice any unusual smells coming from your milk, it is best to discard it.
  3. Taste: Spoiled milk may have a sour, bitter, or metallic taste. You may also notice a slight tingling sensation in your mouth when you drink it.
  4. Unusual color: Fresh milk is typically white or slightly off-white in color. If the milk appears yellowish, bluish, or discolored in any way, it may be spoiled.
  5. Expiration date: Milk has a limited shelf life (4-5), so it is important to check the expiration date on the carton. If the milk has expired, it may have already gone bad and should be discarded.

It is important that you always check the expiration date on your milk carton and store it properly in the refrigerator to extend its shelf life (4).

Can you get sick from drinking spoiled milk?

Yes, drinking spoiled milk can make you sick, as it contains harmful bacteria that can cause food poisoning (1, 6-7). The main symptoms of food poisoning from spoiled milk include:

  • Nausea: You may feel nauseous or have an upset stomach after consuming spoiled milk.
  • Vomiting: You may experience vomiting, which is your body’s way of getting rid of the harmful bacteria (8).
  • Diarrhea: Consuming spoiled milk can cause diarrhea, which can lead to dehydration if left untreated.
  • Abdominal pain: You may experience cramps or abdominal pain after drinking spoiled milk.
  • Fever: In severe cases of food poisoning, you may develop a fever.

If you experience any of these symptoms after drinking spoiled milk, it is important to seek medical attention if the symptoms persist or worsen.

It is very important to know that it is essential that you always check the expiration date on milk and discard it if it has gone bad to prevent food poisoning!

What should you do if you suspect you have consumed spoiled milk?

If you suspect you have consumed spoiled milk, there are several actions that could help you to reduce the risk of illness or severe infections:

  • Stop drinking the milk immediately: If you notice any signs that the milk has gone bad, such as an unusual odor or taste, stop drinking it and throw it out right away.
  • Check for symptoms: Keep an eye out for symptoms described above, such as nausea, vomiting, diarrhea, abdominal pain, and fever (8-9).
  • Stay hydrated: If you experience diarrhea or vomiting, it’s essential to stay hydrated by drinking plenty of fluids, such as water, clear broths, or electrolyte replacement drinks to help recovering (10).
  • Seek medical attention: If your symptoms are severe or last more than a few days, seek medical attention. Your doctor may recommend over-the-counter medications or prescribe antibiotics, depending on the severity of your illness.

It is very important that you store your milk properly as it will be described in the next sections to prevent food poisoning.

Do not forget to always check the expiration date of your milk before consuming it!

How should you handle milk to prevent spoilage?

You can prevent spoilage and prolong the shelf life of your milk by following the following tips:

  • Store it in the refrigerator: Milk should be stored in the refrigerator at a temperature of 40°F (4°C) or below (11). It’s important to keep milk away from the refrigerator door, as temperature fluctuations can affect its quality (11).
  • Keep it covered: Milk should be kept in a covered container to prevent contamination and exposure to light.
  • Don’t mix old and new milk: Don’t mix fresh milk with milk that is close to its expiration date or has been opened for several days, as this can accelerate spoilage.
  • Don’t leave milk out at room temperature: Milk should not be left out of the refrigerator for more than two hours. If milk is left out for longer than this, it can quickly become a breeding ground for bacteria (12).
  • Don’t return unused milk to the original container: If you have leftover milk that you didn’t consume, don’t return it to the original container, as this can introduce bacteria and contaminate the remaining milk.
  • As mentioned, several times before, you should check the expiration date: Always check the expiration date on the milk carton before consuming it. Milk that has expired should be discarded.

By following these simple guidelines, you can help prevent spoilage and ensure that your milk stays fresh and safe to consume.

The shelf life of milk can vary depending on the type of milk and how you stored it. For example:

For fresh milk: Fresh milk has a shelf life of about 5-7 days when stored in the refrigerator at a temperature of 40°F (4°C) or below (11).

Ultra-pasteurized milk: Ultra-pasteurized milk has been heated to a higher temperature than regular milk, which gives it a longer shelf life (4). It can last up to 2-3 weeks in the refrigerator when unopened, and about a week after opening.

Shelf-stable milk: Shelf-stable milk is treated with ultra-high temperature (UHT) to kill all the bacteria and extend its shelf life (4). It can be stored at room temperature until opened and can last for several months in the refrigerator after opening.

Be aware that the actual shelf life of milk can vary depending on various factors, such as the temperature of the refrigerator, how it was handled during transportation and storage, and whether it was opened or not (4)

How to properly dispose of spoiled milk?

Here you can find some general tips on how to dispose of spoiled milk properly to prevent the spread of bacteria and avoid unpleasant odors:

  • Pour the milk down the drain: Pour the spoiled milk down the drain and run cold water for several seconds to ensure that the milk is flushed away.
  • Clean the container: Rinse the container with soap and water to remove any remaining milk residue, and then sanitize it with a mixture of water and vinegar, soap or bleach to kill any bacteria.
  • Do not pour down the toilet: Do not pour spoiled milk down the toilet, as this can cause clogs and other plumbing issues.

Finally, remember that you can also consider composting spoiled milk along with other organic waste to add value to your residues!

It is never too late to go green!


In this brief article, we answered the question “how to know if milk is spoiled”, and discussed the different methods of identifying spoiled milk and the potential health effects of drinking spoiled milk.


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