How long can cow milk sit out? Do you know? While grocery store milk that’s been pasteurized can go bad really quick if left out, raw milk acts differently. If you’re not familiar with raw milk, keep reading! I promise you’ll learn something new. And dare I say that maybe by the end of this post you will be ready to get your own dairy animal?
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First, let’s address the elephant in the room and acknowledge that there is a LOT of controversy about drinking raw milk. In my humble opinion, milk pasteurization absolutely has a place in our society. We don’t all live on farms or have access to or money for farm products. However, if you have your own dairy cow or have access to raw milk, the raw milk is a much better product.
This post will answer the question of how long cow milk can sit out on your counter. While I will be talking about raw cow milk here, this post would apply to any dairy animal you have.
Safety is very important, so let’s go over some things to keep in mind when handling raw dairy.
Safety Tips for Raw Milk
This list is really hard to rank because I think each item is equally as important as the next.
You should keep these priorities in mind if you are milking your own cow. If you are purchasing raw milk from a local dairy farm, inspect their milking and processing procedures to make sure you feel comfortable with their process. Be your own advocate and don’t spend your money if they won’t let you see them work.
Priority #1 – Make sure your dairy animal is healthy.
This should be common sense but make sure your dairy animal is healthy. You can have her tested and analyzed for different diseases but generally if she looks and acts healthy and her baby looks and acts healthy and is growing well, her milk is likely safe to drink.
However, if your dairy animal is showing signs of sickness (coughing, lethargic, emaciated, etc), you may want to hold off on drinking her milk until you determine why she’s sick.
If you have your own dairy animal, make sure to allow her access to fresh pasture and plenty of sunshine and clean water to keep her healthy.
Priority #2 – Cleanliness is critical when working with raw dairy.
If you milk your own dairy cow or if you buy raw milk from a local dairy farmer, cleanliness is critical for keeping your milk safe and fresh.
Every vessel that the raw milk comes into contact with needs to be very clean. I like to sanitize the milk pails, funnel, and milk jars in my dishwasher immediately after use. Also, make sure that the cow’s udder is cleaned very well prior to milking her. We use hot water and a bit of Dr. Bronner’s liquid castile soap to wash Belle’s udder.
Here’s our experience although hopefully it’s not everyone’s experience. We bought raw milk for years prior to moving to our farm. And we purchased raw milk from two separate farms that were very reputable.
I’m not sure what those farmers were doing wrong but all the milk we ever purchased had kind-of a grassy flavor. It was not pleasant but I assumed that maybe that’s how raw milk was SUPPOSED to taste. So we kept buying their milk!
Fast-forward to us milking our own dairy cow and being mindful of cleanliness in every step of the process. I have NEVER tasted any grassy flavor in Belle’s milk. EVER! She’s a Jersey cow just like the other two farms used; however, our milk actually tastes like good, sweet milk. I’m guessing maybe cleanliness or filtration was an issue at those other farms.
Priority #3 – Filtering your milk with high-quality filters is essential.
If you are milking your own dairy animal, I really recommend high-quality raw dairy filters for getting the tiniest bits of dust and debris out of your raw milk.
As a general rule, if your milk is clean going into your milk jars, it will be sweeter and will stay sweet for longer in your refrigerator without developing off-flavors.
Priority #4 – Chill your filtered, raw milk as soon as you can.
It shouldn’t be a surprise that when you milk your dairy animal, it will be close to 100°F (38°C). All of the good, alive things in raw milk are active at that temperature and feed on the sugars. You’ll want to arrest them by refrigerating and chilling your milk as soon as it’s filtered.
The best way to store your milk is in the bottom or back of the fridge. The refrigerator door is not recommended since that is usually the warmest spot. This applies to any type of milk products or raw dairy products (cow’s milk from whole milk to skim milk, either non-organic or organic milk, breast milk, soy milk, almond milk, oat milk, lactose-free milk, and regardless of whether it’s raw milk, pasteurized milk, or ultra-pasteurized milk. Milk that’s gone through ultra-high temperature pasteurization…also known as shelf-stable milk…does not need to be refrigerated.
We only milk Belle so it’s easy for us to milk her, filter the milk, and get it into our refrigerator within an hour of milking. Her milk is really sweet for at least 5 days before the sugars start decreasing but even at 10 days her milk still tastes better than milk from the grocery store. Grocery store milk is usually good for 1 to 5 days past the expiration date or the sell-by date.
Clemson University did a study on the safe handling of milk and dairy products that you might find interesting. They say that milk should be stored well below 40°F (4°C) to protect the milk’s quality. Otherwise, it will start to show signs of spoilage like curdling and developing a sour odor and off-flavors. We set our refrigerators at a safe temperature between 37°F and 39°F (3°C to 4°C).
So How Long Can Cow Milk Sit Out?
Answer: Raw cow milk is full of good, alive things that keep it safe almost indefinitely when it is left out. The good guys outnumber and kill off any bad guys that might be introduced. However, milk will start to turn sour after one day out. But sour milk is great for making waffles, cornbread, and marinades, so don’t throw it out! After the second day, raw milk will clabber and turn into a yogurt and cheese-like consistency. The whey separates from the fat particles during this time but it’s still perfectly safe to consume. You are basically culturing your milk as it sits out. The longer it sits out, the more whey comes out of the curds and the end result is similar to sour cheese.
A carton of milk from the grocery store has been pasteurized and all the beneficial things were killed during the heating process. Therefore, there is nothing good left in the milk to fight off small amounts of bad bacteria that may be introduced. By contrast, raw milk doesn’t have to be pasteurized and is actually healthier for you if you don’t pasteurize it.
When pasteurized milk is left out at room temperature it will start to spoil quickly. Food safety experts at the U.S. Food and Drug Administration say that leaving perishable food out for 2 hours or more allows harmful bacteria and spoilage bacteria to develop rapidly. Furthermore, the time frame is 1 hour when the temperature is 90°F (32°C) or hotter. They have additional information and specify that the danger zone for food poisoning is from 40°F to 140°F (4°C to 60°C).
But raw milk is different! So don’t be frightened to let your raw milk sit out to sour and clabber.
Experiment: How Long Can Cow Milk Sit Out?
In order to prove what I say above regarding the safety of leaving raw milk out on the counter, I did an experiment and documented the results. It’s fascinating how raw milk changes and cultures from one product to another product entirely!
Day 0 of How Long Can Cow Milk Sit Out?
I poured a cup of cold, fresh milk and left it on the counter. It tasted sweet and good.
Day 1 of How Long Can Cow Milk Sit Out?
After 24 hours, the cup of milk still looked like milk but I could see that the fat particles were starting to come together. It smelled only slightly sour.
Day 2 of How Long Can Cow Milk Sit Out?
After 48 hours, the cup of milk had definitely started separating into curds and whey. It did smell sour and I had no desire to taste any of it.
Day 3 of How Long Can Cow Milk Sit Out?
After 72 hours, the cup of milk had separated even more into curds and whey. The volume of whey had doubled and I poured off the whey into a separate glass. Interestingly, the smell was starting to turn sweet again and was less sour. I have no idea if that is normal for raw milk, or Belle’s milk, or for my kitchen environment.
Because it smelled sweeter and I was curious, I tasted the curds after I poured off the whey. It tasted a lot like tangy yogurt!
Day 4 of How Long Can Cow Milk Sit Out?
After 96 hours, more whey came out of the shrinking curds and I decided to drain it in a flour sack towel hanging from my upper cabinet door knob.
I tasted the curds and they tasted more sour than the previous day and less desirable. I’m thinking that sour cheese probably doesn’t have a market. But Day 3 cheese…that’s another story!
I do want to stress that the smell and taste of the raw milk (and eventually curds) went from sweet to sour but it never got to the level of putrid like it was bad milk or rotten milk. Culturing and fermenting happens naturally in a raw dairy product and it is still safe to consume. Fermented milk products are created when milk ferments with specific kinds of bacteria called Lactobacilli or Bifidobacteria. These are already present in raw milk and are the most well-known probiotic organisms.
I stopped the experiment on Day 4 because I was pretty sure the curds would continue to shrink and get more sour as time went on. But I didn’t throw out the curds and whey!
Since the curds and whey were cultured and full of good bacteria, I gave them to the dogs and chickens who gobbled them up fast.
I hope this post was informative and maybe calmed your fears about the safety of consuming raw milk!
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