How Long Can Milk Sit Out


As per the guidelines from the US Food and Drug Administration, at room temperature milk can sit out no longer than 2 hours. In hot countries, this further reduces down to 1 hour.

While milk is a normal part of your household, it is not unusual to have questions regarding its shelf life. For example, can you drink milk that slept on the counter overnight? Is it safe after sitting out for a few hours or the whole night? If you have ever asked yourself these questions, you are at the right place.

In this article, we address issues surrounding the shelflife of milk and does milk go bad. Read on to discover.

milk sitting out

How Long Does Milk Last If Not Refrigerated?

How long milk can sit out when not refrigerated depends on the background and condition of the milk but the guideline from the USFDA is 2 hours. Therefore, the amount of time milk will sit out will depend on whether it underwent ultra-high temperature treatment, pasteurization, or did not undergo any treatment. We expound more below on milk and food safety precautions you can take.

Fresh Milk

Fresh milk is that which has not undergone any processing. Therefore, this type of milk is generally expected to have a short shelf life, even if sealed.

Even when the milk carton has not been opened and the seal is not broken, pre-existing bacteria will cause the milk to spoil. Some of the bacteria that are already present in raw milk that may lead to spoilage include:

  • Salmonella
  • Listeria
  • Campylobacter
  • E Coli

Raw milk can especially be dangerous as these bacteria can make people sick and are always present just as the milking begins. The bacteria will then multiply and lead to the spoilage of the milk.

On the other hand, breast milk can sit out for up to 4 hours once expressed and stored in a sealed container.

Unopen Pasteurized Milk

Pasteurization of milk kills bacteria as the milk is heated at ultra-high temperatures. Once the microorganisms in the milk are destroyed, the milk is sealed in aseptic packs to ensure that it has a long shelf life. Unopen whole milk usually stays for as long as five to seven days after the demarcated expiry date.

However, opening the milk packet alters the dynamics as pathogenic microorganisms will eventually cause the milk to spoil.

Milk is heated to about 161 degrees Fahrenheit during vat pasteurization, making this milk safer than raw milk but not as safe as UHT. Therefore, this milk is likely to go bad if left overnight. However, if open, pasteurized milk will last between three and six hours. Interestingly, the milk will not turn sour if left out overnight. Instead, it will just go bad.

Unopen UHT-Treated Milk

Milk treated to ultra-high temperature treatment is superior to pasteurized and raw milk as it will last longer than these two milk types. Therefore, it is shelf-stable milk that you can keep out long after grocery shopping.

It is treated to higher temperatures than pasteurized milk (280 degrees Fahrenheit for two seconds). As a result, this milk has a long shelf life and can stay up to six months after processing if the seal is left intact. Therefore, organic milk lasts longer than fresh and pasteurized milk.

Therefore, you can safely leave your unopen milk on the shelf for months without worrying that it will spoil. However, you should keep the milk refrigerated once opened as it will spoil if left out of the fridge.

Is it safe to drink milk left out overnight?

It is generally not safe to leave milk out of the fridge or refrigerator overnight. It is safer to keep pasteurized and raw milk in the fridge, and it should not sit out for more than two hours. However, the amount of time milk can sit out before you start sensing signs of spoilage may depend on factors such as the temperature inside your house.

Also See: Does Almond milk go bad?

Milk in the Refrigerator

milk fridge

Ideally, milk should be stored below 40 degrees Fahrenheit. If not, you will feel that the flavor is off and the smell is sour. If you are unable to store milk in a fridge, you can store it with ice packs.

Ideally, you should keep your milk in the coldest section of your fridge. However, placing it near the door can be detrimental as the temperature around the door fluctuates greatly.

If you have more milk than you can drink within a safe time range, you should consider storing it in the freezer. You can keep it there for up to a month, after which the taste might slowly start changing. After that, it is best to freeze your milk in its original container. However, if your milk is in glass or cardboard packaging, it is best to pour it in freezer-safe plastic containers before freezing it.

Alternatively, you can pour the milk into ice cube trays and freeze the milk in the trays. After this, you can transfer the milk cubes into a freezer bag and keep them in the freezer.

How to Know If Your Milk is Going Bad

If you want to know whether the milk you are dealing with has been left out for too long or is going bad, you have to make use of your senses.

The most efficient tool you have in your battalion is your nose, whether the milk was in the refrigerator or it was left on the shelf.

The bacteria in milk produces lactic acid. Over time, this acid causes a distinct sour smell in milk, which is usually the first sign of spoiled milk.

Apart from the smell, the milk will become lumpy with a yellow tinge. If you notice these signs, it is probably time to pour the milk so nobody else can drink it.

Tips to Keep Your Milk Fresh As Long As Possible

milk outside

As you buy milk, there are some things you can do to ensure that the milk lasts as long as possible.

  • Pick out the milk last at the grocery store so that it can stay cool and refrigerate it as soon as you get to the house.
  • Store and serve your milk at 40 degrees Fahrenheit and below as this maximizes the flavor and extends shelflife.
  • Store your milk in the coldest refrigerator parts as the temperatures are more unstable near the doors.
  • Buy UHT treated and pasteurized milk as these have been treated to prevent health risks associated with drinking raw milk. They also last longer. However, you mustn’t leave the milk not refrigerated for long.

How long does unopened milk sit? Unopened milk may sit for as few days or as long as a month, depending on whether it is pasteurized or UHT treated. However, breast milk may sit for as long as 4 hours on the shelf or four days in the refrigerator. Therefore, ensure that once the milk is out of the refrigerator, you can consume it as soon as possible.


Is it safe to drink milk left out overnight?

As per the guidelines from the US Food and Drug Administration, milk should not be left out of the fridge for more than 2 hours. Milk should be stored in the refrigerator at all times.

How long can breast milk sit out

Breast milk can sit out for 4 hours providing it is properly sealed.

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