We’ve all been there. You take the milk out of the fridge, notice something is slightly off, turn to your roommate or a family member, and ask, "Does this smell funny to you?"
Milk is a touchy thing. It’s a staple in most kitchens, yet it also has a fairly short shelf-life. And, as Business Insider reports, expiration dates are estimates and can vary wildly between products. Healthline also notes that strictly following expiration dates is responsible for up to 20% of America’s food waste.
If properly refrigerated, milk can still be drinkable up to a week after its expiration date. So, while a passed "use by" date is an indication that your milk might be on the brink of spoiling, that doesn’t mean you should immediately pitch it. You’ll have to do a little more inspection to reach that conclusion.
Thankfully, there are several ways to figure out if your milk has gone bad — and they don’t necessarily involve using a loved one as a guinea pig. They involve using your senses.
The nose knows
The first way you’re probably going to be tipped off that something might be wrong with your milk is the smell. According to Healthline, the best way to tell if milk has spoiled is to give it a sniff.
You’ll get your answer pretty quickly if it has truly gone bad. Spoiled milk gives off a very sour smell that’s so distinct it’s hard to mistake.
The Daily Meal explains that the reason milk gets so pungent — the outlet compares the smell to sewage — when it goes bad is that bacteria begin to break down the lactose in the drink. The smell is a chemical byproduct of this process, and it’s sure to repel you instantly.
"Your nose is a very very sensitive tool and it gives you something that says the milk is no good at that time," said Theodore Labuza, food safety expert and professor at the University of Minnesota’s Department of Food Science and Nutrition, per Business Insider. "If you drank it, you’d probably throw up. It’s not food poisoning, it’s food objection."
Something looks off
So what if the sniff test doesn’t result in a clear conclusion about your milk? Use your eyes to detect other signs of spoilage.
Business Insider reports that there are multiple physical signs that milk has gone bad, both in color and texture. Unspoiled milk should be bright white and smooth in consistency. If you pour a glass of milk and it looks yellowy or curdled chunks hit your Cheerios when you douse them with milk, stop what you’re doing, and fix yourself something different for breakfast.
But don’t throw it out just yet. You can actually use sour milk to make pancakes and other dishes, since, according to NPR, cooking with spoiled milk does not carry the same risk of food poisoning, which may result in nausea, stomach pain, vomiting, and diarrhea. Instead, spoiled milk works like a buttermilk substitute — as long as it hasn’t developed mold.
The ultimate taste test
Finally, if all else fails and you still can’t tell if your milk is past its prime, there’s one more of the five senses you can utilize to find out: taste. As mentioned via Business Insider, milk that has gone fully bad is full of bacteria, which lets off a foul odor. That same bacteria produce a sour flavor that will likely make you gag.
If you’re lucky, that should be the end of your spoiled milk experience. As Healthline notes, even if you swallow bad milk, one or two sips shouldn’t be enough to cause serious damage beyond a disgusting aftertaste.
However, if you do consume too much spoiled milk, make sure to stay hydrated while it works its way through your system. The CDC notes that people experiencing food poisoning or extreme dehydration after drinking bad milk should seek medical attention.