How do I know if milk is spoiled?

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

How do I know if milk is spoiled?

There are different easy indicators that can help you to identify whether your milk has spoiled:

Important: it is important to be careful and mindful of the potential health risks associated with consuming spoiled milk, as it can lead to food poisoning and other adverse health effects (1-3).

  • Appearance: in terms of appearance, fresh milk typically exhibits a smooth and consistent texture, accompanied by a uniform color and a slightly creamy consistency. 

However, when milk turns sour or spoils, noticeable changes occur. It may develop a chunky or curdled texture, appearing thick and potentially acquiring a yellowish or bluish hue.

  • Smell: when it comes to the smell of spoiled milk, it possesses a distinct and easily recognizable aroma. It is often described as sour, unpleasant, and rancid. 

If you detect any unusual or off-putting odors emanating from your milk, it is advisable to discard it to ensure your safety.

  • Unusual color: Fresh milk typically exhibits a white or slightly off-white coloration. However, if you observe any yellowish, bluish, or any form of discoloration in the milk, it may indicate spoilage.
  • Expiration date: Milk has a limited shelf life (4-5), so it is important to check the expiration date on the carton. If it expires, you should immediately discard it.

Can you get sick from drinking spoiled milk?

Yes, drinking spoiled milk can make you very sick, you should be careful as it contains harmful bacteria that can lead to food poisoning (1-3).

Food poisoning resulting from spoiled milk can lead to various symptoms, including nausea, abdominal pain and vomiting, which may manifest as an upset stomach following the consumption of spoiled milk (1-3, 6-7). 

Consuming spoiled milk can also cause diarrhea, which, if left untreated, can lead to dehydration (7). 

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

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.

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.


In this brief article, we answered the question “how do I 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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