How Long Can Milk Sit Out Of The Fridge?

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If your milk is pasteurized, you might think it’s fine to leave it on the counter or kitchen table for hours at a time. But is that true? How long can milk sit out before it becomes unsafe to drink?

Dairy products such as milk should not sit out longer than two hours at room temperature and even shorter when the temperature rises. Harmful bacteria grow quickly in milk between 40°F and 140°F and can make you sick when consumed.

In this article, I’ll explain more about leaving milk out and what might happen if you decide to use milk that has stayed out for too long.

How Long Can Milk Sit Out?

According to the USDA, milk should not be left out for more than 2 hours at room temperature. It needs to be refrigerated below 40°F and opened may be kept up to 1 week at best.

So, if you’ve left your milk out on the counter for half an hour, and your kitchen isn’t as hot as Hell’s Kitchen, it’s probably fine if you put it in the fridge.

milk sitting on counter for smoothie

However, you shouldn’t leave it out repeatedly because that gives bacteria the opportunity each time to grow and grow. Refrigerating doesn’t stop them or shrink their colonies. It only slows their growth.

You probably already know that you shouldn’t keep milk out of the fridge for too long, but what are the consequences of doing so?

If you’re like me, you sometimes forget to put the milk back in the fridge after you use it.

How Cold Does Milk Have To Be?

Milk should be kept below 40°F to remain as fresh as possible.

When grocery shopping, buying your meat, milk or alternatives, and frozen items at the end of your trip is always a good idea. That help avoid them sitting in your cart for long and later in your car for the journey home.

The best way to keep your milk cold is to put it in an insulated bag with other cold items.

Don’t be afraid to pack them with frozen veggies. Your milk shouldn’t freeze by the time you get home.

Why Does Milk Spoil At Room Temperature?

Many factors determine the shelf life of milk, but when the temperature remains in the danger zone, spoilage bacteria quickly multiply to dangerous levels that could make you sick.

Even pasteurized milk can contain bacteria that survived the process or have been introduced after opening.

In the beginning, their numbers are small and shouldn’t pose much of a threat to you, but as the temperature rises and remains warm, they can double their size in as little as 20 minutes.

The toxins these bacteria create can cause food poisoning and may require you to seek medical treatment quickly.

How Long Can Ultra-Pasteurized Milk Be Left Out?

An unopened carton of ultra-pasteurized milk should last up until its expiration date if stored in a cool, dry place. However, opened ultra-pasteurized milk should be treated the same as fresh milk.

buying pasteurized milk grocery store

As I mentioned above, bacteria that may be floating in the air or on just about every surface can make their way into your milk and spoil it quickly.

You might be able to keep the ultra-pasteurized in your pantry for years, but store it in the fridge as soon as you open it.

Will Milk Go Bad If Left Out Overnight?

Yes, milk will go bad overnight, both opened and unopened, if left out. It will no longer be safe to consume, and you should discard it immediately.

Even if you don’t sense any signs of spoilage, such as smelling bad, which I’m sure it will, you cannot use it for anything.

It’s often the things you can’t see, such as microbes and bacteria, that are the ones that can hurt you the most.

Milk Sitting Out FAQs

Is It Okay If I Left Milk Out For 3 Hours?

It’s not okay to leave your milk out for 3 hours unless the temperature is below 40F where it has been sitting. To avoid foodborne illness, you should dump the milk so that no one drinks or uses it.

How Long Can Milk Stay In The Car?

Avoid keeping milk in your car for long periods of time, especially on hot days. As little as 30 minutes on a hot day in your car could cause it to spoil. Use a cooler or insulted bag with ice packs to keep it cold until you get home.

Where Should I Put My Milk In The Fridge?

You should put your milk in the lower half of the fridge at the back, where it is consistently the coldest. Storing milk in the fridge door is the worst spot in the fridge because it is the area most affected by temperature changes.

Written By Justin Micheal

Justin is not just the creator but also an author and editor for KitchenSanity. He does the majority of the cooking at home with his wife. His friends and family look forward to eating his delicious creations, which often leads to many questions about how they can replicate his meals at home. In his writing, he shares his passion and knowledge as a home chef from his kitchen to yours.