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How Long Is It Safe To Leave Milk That’s Been Unopened Sitting On Your Counter?

Milk is such a temperamental thing. This is a versatile ingredient that is consumed every day by people around the world. However, it is also very sensitive to temperature. You will need to ensure that you store your milk properly so that it will be safe for you to consume.

So how long is it safe to leave your unopened milk out on the counter?

How long is it safe to leave milk that’s been unopened sitting on your counter

Today, we’re going to cover all there is to know about your unopened milk so that you can ensure that it is safe for you and your family to consume. Let’s learn more about the general shelf life of UHT treated, pasteurized, and raw milk.

Is It Safe To Leave Unopened Milk On Your Counter?

The length of time that it is safe to leave your milk out on your counter will entirely depend on the type of milk that you have bought. The vast majority of milk has either undergone UHT treatment or pasteurization.

But there are also some types of fresh milk and raw milk that haven’t been through any kind of heated treatment.

Fresh, raw, and pasteurized milk will not be able to last outside of your refrigerator for long. This is because once the milk warms up, it starts to go bad quicker.

However, UHT treated milk has been designed to sit out at room temperature as long as it has been unopened. A bottle of unopened UHT milk will be able to sit out on your counter for around 6 months before it goes bad.

How Long Does It Take Pasteurized Milk To Go Bad?

So what about pasteurized milk? The whole process of pasteurization has been designed to kill off any harmful bacteria in the milk itself. This happens by heating this milk to reach higher temperatures until the bacteria has been killed off.

This process works to destroy any bacteria that could be lurking in your milk. 

This milk is then sealed to ensure that it lasts for longer. When this seal has been broken, the exposure to the air and more bacteria can cause the milk to start to go bad.

The process of pasteurization sees the milk heated to around 161℉ for around 15 seconds or so. This is enough to kill off any harmful bacteria that could be in the raw milk. However, it’s worth noting that this won’t be as safe as UHT treated milk. But it will be much better than raw milk that hasn’t been pasteurized.

You will also need to store your pasteurized milk in your refrigerator to ensure that it is safe to consume. Leaving your bottle of unopened pasteurized milk on your kitchen counter overnight can be enough to make it spoil.

This will especially be the case if you have broken the seal and used it in the meantime, then accidentally left it out.

Your pasteurized milk can typically only survive at room temperature for around 4 hours. Depending on other factors, it could last for anywhere between 3 to 6 hours. If you have left your unpasteurized milk out overnight, you should get rid of this and buy a new bottle just to be on the safe side. If your milk smells off, you should never drink it.

How Long Does It Take Sealed UHT Treated Milk To Go Mad?

Unlike its raw or pasteurized counterparts, UHT treated milk has been designed to last at room temperature providing the bottle hasn’t been opened. This is why you will often see that UHT milk is usually sold and processed while at room temperature.

Ultra High Temperature milk is usually heated to around 280℉ for around 2 seconds. This is enough to kill off harmful bacteria, and ensure that the milk is able to survive at room temperature once it has been packaged in a sealed bottle.

So UHT milk can sit out for much longer on your counter than pasteurized or raw milk can.

The average lifespan of a bottle of unopened UHT milk is around 6 months. If this seal is broken, it will need to be refrigerated. The only exception to this rule is if you opt for a Tetra pack of UHT milk. This will need to be refrigerated at all times, just like raw and pasteurized milk.

How Long Is It Safe To Leave Raw or Fresh Milk Out On Your Counter?

It’s important to remember that unlike UHT and pasteurized milk, fresh or raw milk doesn’t have any heating process applied to it before it is sold to the consumer.

So it will have a much shorter shelf life, even if you leave the seal of the milk intact.

You will need to keep this milk refrigerated at all times. Especially if the seal has been broken. This is because a broken seal allows bacteria to infiltrate the milk, which then causes it to spoil.

It’s also worth noting that some bacteria remain intact from the milking process, as these haven’t been killed off through heat. So these can cause the milk to spoil quicker, even if the seal has remained intact.

Some of these bacteria include salmonella, campylobacter, listeria, and e coli. These all have a reputation for causing people to become very ill.

What Can Affect The Average Shelf Life of your Milk?

How long is it safe to leave milk that’s been unopened sitting on your counters

Other factors that can affect the shelf life of your milk include the handling and processing once it has been harvested on the farm. If the proper procedure hasn’t been followed to ensure that the milk has been packaged and processed properly, this can of course shorten the lifespan of your milk, regardless of which type that you opt for.

Temperature control is very important when it comes to storing milk. This is because if your milk hasn’t been stored at the properly refrigerated temperature during the transportation from the farm, to the processing factory, to the grocery store, its safety would have been compromised.

So unless you opt for UHT milk that specifically says it can be stored – unopened – at room temperature, you should always place your milk in your refrigerator the moment you get home from the grocery store. If it has been stored at a cold temperature, then it will likely still be safe to consume. However, if you are in doubt as to the integrity of your unopened or even opened milk, it will be best to pour it down the drain and buy a new bottle.

Frequently Asked Questions

How Warm Can Milk Get Before It Goes Bad?

On average, your milk shouldn’t be allowed to get to more than 40℉. Anything above this can cause the milk to start to spoil. Your milk should be stored in your refrigerator at all times.

UHT milk is safe to leave at room temperature, but only if the bottle hasn’t been opened. Open UHT milk will need to be stored in the refrigerator.

What Happens If I Drink Milk That’s Been Sat Out?

If you were to drink milk that has been sitting out of your refrigerator for any length of time, you could give yourself food poisoning. Even if the food doesn’t appear to have a sour aroma or is lumpy in appearance.

This is because bacteria start to multiply if the milk has been left out at room temperature for longer than 4 hours. This will especially be the case if the milk has been opened.

How Long Does It Take For Unopened Milk To Spoil?

If your unopened milk has been left out on the counter, it could take it up to 4 hours to spoil, especially if you have opted for raw, fresh, or pasteurized milk. If you have kept your milk in the refrigerator, it could take between 5 to 7 days to spoil.

Your milk will typically come with a use by date to give you an idea of when it’s safe to consume.

Can Unopened Milk Be Left Out Overnight?

You can only leave unopened UHT milk out overnight. If you have raw, fresh, or pasteurized milk, this will need to be refrigerated immediately. If you leave these types of milk out at room temperature overnight, these will likely spoil and be unsafe to drink.

In Summary

So there you have it! The general rule of thumb is that your unopened milk won’t be able to last for more than around 4 hours if you have left it out on the counter and forgotten to put it back in the refrigerator.

You can always smell the milk to make sure. If it has a sour aroma or a lumpy appearance, then the milk has gone bad and shouldn’t be drunk. The only exception is unopened UHT milk, which has been designed to last for around 6 months providing the seal remains intact.

Jess Smith