Don’t Drink Spoiled Milk: Here’s Why

You’re probably here because you’ve just consumed milk that’s past its expiration date or you are considering consuming milk that’s past its expiration date (or smelling a little off). Either way, here’s what you need to know.

What Does “Sell-By” Mean?

There’s a big difference between “sell-by” and “use-by” labels. The sell-by date exists to tell grocery stores (and consumers) when the carton or jug should leave shelves because it is approaching its peak freshness. However, this date doesn’t mark the point when a food item goes “bad.”

“Best-by,” meanwhile, is the date the manufacturer estimates the product will be at its most fresh. While this “use-by” date is also not a line in the sand, you should take this date more seriously when you are deciding whether to consume a product. This is when the manufacturer estimates the product will begin to lose significant quality.

How Long Does It Take For Milk to Go Bad In the Fridge?

This depends on what kind of milk you’re talking about. If the unopened container is refrigerated:

  • Lactose-free milk should be good for 7-10 days past the printed “sell-by” date.
  • Non-fat milk should be good 7-10 days past the printed
  • “sell-by” date.
  • Reduced-fat milk should be good 7 days past the printed
  • “sell-by” date.
  • Whole milk should be good 5-7 days past the printed
  • “sell-by” date.
Jose A. Bernat Bacete/Getty Images

What If You Accidentally Left It Out?

Unrefrigerated milk is a very different story.

If you live in the U.S., you likely drink pasteurized milk. This type of milk must be refrigerated constantly, or else it will quickly begin to spoil. We get it, though: It’s super easy to get distracted and leave a carton of milk in the car or on the counter for an extended period of time. But just how long is too long?

According to the Food and Drug Administration (FDA), the magic number is two hours at room temperature. After the two hour mark, the milk is likely not safe to drink. If your house or car is hot, though, the window is even smaller.

“If the temperature is above 90°F, food should not be left out more than 1 hour,” according to the FDA.

How to Tell If Milk Is Bad

Texture/Color: Fresh milk is smooth, thin, and white. Spoiled milk may be lumpy, thick, and/or slightly yellow.

Odor: Sour milk smells, well, sour. Fresh milk has barely any odor — and what odor it does have is not unpleasant. When you smell spoiled milk, you’ll definitely know something is off.

Taste: If your milk looks and smells unpleasant, please don’t taste it. However, if you simply must taste the lumpy, foul-smelling liquid, it’ll have an acidic, sour flavor.

What Happens If You Drink Spoiled Milk?

Spoiled milk looks, smells, and tastes bad because of an overgrowth of bacteria. Most people are immediately turned off once they’ve taken a sip of milk that’s past its prime. That’s a good thing, because one sip won’t hurt you. However, drinking a large or moderate amount of bad milk can result in digestive discomfort.

Spoiled milk can cause:

  • Abdominal pain
  • Nausea
  • Vomiting
  • Diarrhea

More often than not, these symptoms will alleviate themselves within 12-24 hours. In the meantime, sip on fluids (particularly those enhanced with electrolytes) and rest. If you’re concerned about the severity of your symptoms, go to your local urgent care or call your doctor’s office.

Spoiled Milk Uses

While you certainly shouldn’t drink a glass of spoiled milk or pour it over seriously, your expired milk may not be a lost cause entirely. It really depends on the degree of spoilage; sour milk is okay to use for cooking. As long as the milk isn’t moldy or showing other signs of significant spoilage, you can still use it for baking projects (such as quick breads and cakes), as well as for marinating meats.

So, if your milk is just a few days past it’s “use by” date and beginning to smell sharp, chances are, it’s perfect for using in a recipe like this Sour Milk Spice Cake. That said, if the milk is a week or more past that date and smelling excessively sour, appears lumpy and is off-colored, you should probably play it safe and pour it right down the drain. While the oven temperature is likely to kill off most harmful bacteria, your baked goods may take on something of a funky flavor. The safest rule of thumb is always, when in doubt — throw it out.


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