How Long Can Cow’s Milk Sit Out and Still Be Good?
We’ve all done it. You are putting groceries away or getting something for your kids and the milk gets left out. How long can milk sit out and still be good? Let’s take a look!
The “Danger Zone” of Bacteria
Harmful bacteria begin to activate and multiply at temperatures between 40 degrees F and 140 F. This is not just for dairy products like soft cheeses and hard cheeses, but for any cooked foods.
Do Different Kinds of Milk Matter?
It really doesn’t matter if the milk in question is cow’s milk, goat’s milk, sheep milk, etc. Milk is a dairy product and the time and contamination concerns would be the same. Read on below if you are curious about breastmilk, formula, and nut milks.
How Long Can Cow’s Milk Sit Out?
According to the CDC (United States Center for Disease Control), milk can sit out for two hours at an average temperature. If you live in warmer temperatures (say 90 degrees F) then it can only sit out for an hour. This would be the same for opened and unopened milk.
This is because milk, even if pasteurized, still can contain bacteria. Bacterial growth begins to kick into gear around 40 F. The milk already has the bacteria in it, so even if it hasn’t been exposed to the air it will still start to spoil.
It does not matter if it is a carton of milk or a plastic jug.
Signs of Spoilage
Spoiled milk is pretty hard to miss! It will smell sour, rancid, and just plain gross. Always check the expiration date on milk. So long as it has stayed cold and is before the expiration date you should be good to go.
Risk Areas to Watch For
It can be easy to lose track of places you might have milk just sitting around the house, especially when you have kids! Places you might not even realize you have milk out and about…
- Sippy Cup
- Bottle of Formula
- Smoothies
- Hot Cocoa
- Bottle of Breast Milk
- Coffee
- Tea
Raw Milk
Aw yes, fresh milk.
Gianclias Caldwell, famous author, cheesemaker, and raw milk utilizer, says in an article Keeping Your Home Milk Supply Clean, “As they say, milk was never meant to see the light of day- it was meant to go directly from the mother into the mouth of her offspring.”
In using milk at all, we are pulling it out of its natural intention, therefore we need to treat it with care to keep it safe.
In her own milk handling, Gianclias says she treats it like ice cream. You would only keep ice cream on the counter while you are using it, then put it away quickly.
If you are adding cultures to the milk, say in making a kefir, then that is a different story.
Some folks intentionally leave raw milk out for creating cream or making clabber.
Personally, unless it is being left out intentionally with the addition of specific cultures, I do not leave raw milk out for longer than the few minutes I am using it.
If I did forget a half gallon out on the counter, I would most likley give it to my chickens.
In the end, how you manage the length of time you leave raw milk out is up to you.
Does Baby Formula Count as Milk?
Baby formula surprisingly follows similar rules to breastmilk. Once mixed with water, formula should be used within two hours or placed in the fridge. Once refrigerated it can be stored for 24 hours before it would need to be disposed of.
Additionally, if you have fed your baby formula from a bottle and they do not finish the bottle, technically it should also be thrown out.
This is due to the fact that the saliva in your baby’s mouth can combine with the formula in the bottle and cause bacteria to grow.
How Long Can Breast Milk be Left Out?
Breastmilk is darn incredible, I like to think of it as the “original raw milk.” According to the Mayo Clinic, breastmilk can be left out at room temperature for up to six hours, though ideally four or less.
Once refrigerated it can last up to three days (the recommend the back of the fridge, not the door). Frozen in a deep freeze, it can last up to a year. For best nutrient value and I’d imagine taste, they recommend using it within six months.
What About Alternative Milks?
If you enjoy oat milk, almond milk, lactose-free milk, or other milk alternatives. According to Epicurious, even milk alternatives should be refrigerated after two hours.
Again, it’s just that magic time where at around two hours the milk is likely going to enter the danger zone for bacterial growth.
Keeping Milk Fresh
The best way to store your milk is in the middle back of the fridge. Avoid the refrigerator door which can have uneven cooling. If you buy milk from the grocery store, always purchase milk that has the latest sell-by date.
Do not place hot leftovers in the fridge as it can cause “hot spots” in the fridge and warm any milk it is by. While this might not activate the spoilage bacteria, it may lead to a shorter shelf life for milk and other foods.
