Here’s How Long Milk Really Lasts—and How to Make It Last Longer

Hundreds of kitchen scenarios—you wake up craving a big bowl of cereal, your cookies need a dunking partner—all end the same way: you, standing at the refrigerator, fingers crossed, nose deep in a carton of milk, praying it isn’t as old as you think it is and hoping it doesn’t have the telltale scent of spoilage. Oh, we’ve all been there, wondering, How long is milk good for after the sell-by date?

Let’s face it: Sell-by dates can be confusing, and they don’t necessarily indicate when food is spoiled. (It’s hard to treat them as gospel when bottled water expiration dates are also a thing!) It’s no wonder so many people doubt whether their milk has truly passed the sniff test and ultimately make an emergency trip to the nearest grocery store to replace the questionable carton.

Udderly confused by the many expiration dates stamped on your gallon of moo juice? We sought out dairy experts to get definitive answers on how long milk lasts, if date labeling is regulated or required by federal agencies like the U.S. Department of Agriculture (USDA) or the Food and Drug Administration (FDA), how to know if milk has gone bad and how to extend its shelf life. As it turns out, you can follow some of the recommended meat storage guidelines or similar strategies to avoid expired eggs, but there are also a handful of milk-specific standards and practices.

How long is milk good for after the sell-by date?

There are a lot of factors that affect how long milk is good for after the sell-by date. The biggest is whether the milk has been through pasteurization, which John A. Lucey, director of the University of Wisconsin’s Center for Dairy Research in Madison, defines as “the process of heating every particle of milk or milk product in properly designed and operated equipment to any of the specified pasteurization time/temperature combinations designed to destroy all human pathogens” in a 2015 paper published in the journal Nutrition Today.

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How long raw milk lasts

Because raw milk has not gone through “a heat step to reduce the microbial count, it will break down and spoil more quickly,” says Amit Shah, senior director of quality at Maple Hill Creamery in New York. He notes that pasteurization is regulated and required to sell milk in mass quantities in America.

According to Alex O’Brien, a food safety and quality coordinator at the University of Wisconsin Center for Dairy Research, that means you’d be lucky to get seven days of drinkability with raw milk.

Until the early 1900s, milk was frequently the vehicle for foodborne illnesses, such as typhoid, diphtheria, scarlet fever and tuberculosis. In 1938, O’Brien says, milk-related products accounted for 25% of recalls. Compare that with today’s 1%. That’s why selling raw milk to the general public is illegal in many situations and states. “It increases risk of foodborne illness significantly because pathogens, including Listeria monocytogenes, Salmonella spp., Campylobacter Jejuni and Mycobacterium bovis, were not destroyed,” he says.

How long pasteurized milk lasts

Pasteurized milk generally lasts three weeks to a month after processing, provided it’s properly refrigerated. That’s regardless of whether it is nonfat, low fat, whole or lactose-free. Cornell University’s Department of Food Science estimates that unopened milk will last two to five days past its sell-by date, though experts say you should be fine for a week. The university recommends drinking an opened container of milk as soon as possible (say, within a few days) for the freshest taste. O’Brien says opened milk is usually good for seven days after the printed date.

Buy aseptic milk, and your carton will last even longer—anywhere from 30 to 90 days when stored properly and unopened. This type of milk goes through ultra-high temperature pasteurization and is packaged in sterile containers in a sterile environment “to ensure no bacteria or pathogens that contaminate milk are introduced,” according to Maple Hill co-founder Julia Joseph. “Aseptic milk is shelf stable and does not need refrigeration until opened,” she says. “Tastes the same, is absolutely safe to drink, and Maple Hill guarantees [its milk] will last for 50 days.”

Ultra-high temperature pasteurization increases how long milk stays good in a sealed container, but once open, the clock starts ticking on it as well. According to the Department of Food Science at Cornell University, you’ll want to drink it within 7 to 10 days of opening.

Do other factors affect how long milk is good for after the sell-by date?

In terms of milk type, the experts all agreed that only two characteristics—whether it’s raw or pasteurized—make a significant difference in determining milk’s quality time frame. They don’t see a big difference in shelf life among skim, low-fat, whole or lactose-free milk as long as they all have gone through the pasteurization process.

Storage details and consumer handling habits play bigger roles in how long milk stays fresh. It’s hard to determine exactly how long milk is good for after the sell-by date because so many things can make milk turn. “There are so many contributing factors that influence how fast milk spoils,” Shah says. “Milk quality at the farm, type of processing, the type of container, temperature while transported, storage temperature, how long it sat open on the table, whether people drink directly from the container.”

Unlike certain foods that should never be refrigerated, milk must be kept cold, according to Megan Holdaway, RDN, a nutrition science manager with the Dairy Council of California. “The ideal storage temperature for milk is between 34 and 38 degrees, and storing pasteurized milk at temperatures above 45 degrees will shorten the shelf life dramatically.”

What do milk expiration dates mean?

According to the FDA, “confusion over date labeling accounts for an estimated 20% of consumer food waste.” People often toss items based on those dates, thinking they indicate when food has become unsafe to eat, but the reality is more complex.

There are no federal laws or regulations requiring manufacturers to place expiration dates on food or drinks, with the exception of baby formula. And there are no uniform or universally accepted definitions for the myriad types of dates that companies use.

The dates are a rough guideline on quality, not safety, according to Holdaway. That’s why it isn’t an exact science to determine how long milk is good for after its sell-by date. “Milk is more than likely safe to drink beyond the date printed on the package,” she says. (There are, however, some foods you should never eat past the expiration date.)

Shah is sure of one thing, though: “The quality of the milk will be reduced after the date printed on the container,” he says.

So, how do manufacturers determine which dates to add to various goods? “Products are dated in one of two ways: a use-by date, which gives an estimated period during which the product will be of best quality, or a production date, a code or series of numbers printed on the label to identify the date and time of production,” Holdaway says. “Meat, poultry, egg and dairy products typically have use-by dates, while canned goods and shelf-stable items have the production date on the outer packaging.”

Ultimately, creameries can choose whether to add a date and what wording to use. O’Brien adds that some labels target the consumer, while others are more helpful to retailers and stores, suggesting when the inventory should be rotated or pulled from shelves.

Expiration dates, explained

The following are some of the most likely dates you’ll find stamped on food and beverage packages.

• Best by, or best before: Indicates the date by which you should consume a product for quality and sensory purposes. This label targets the consumer. The FDA’s preferred label is “best if used by.”
• Sell by: Tells the store how long to display the product for sale. Retailers rely on these dates for inventory management.
• Use by: The last date recommended for using the product at peak quality. It doesn’t indicate food safety, except when used on infant formula, according to Holdaway.
• Expires by: You won’t see this on dairy products, according to Mark Johnson, assistant director of the University of Wisconsin Center for Dairy Research. But you may notice it on other items.
• Freeze by: Indicates when you should freeze a product to maintain peak quality.

Most producers also use a color-coded labeling system for milk, but colorful caps and labels don’t have anything to do with milk safety or drinkability timelines. Those are all about the percentage of fat in the milk.

How do you tell if milk is spoiled?

Although there are foods that never expire like honey, sugar and salt, milk most definitely doesn’t fall in that category. A buildup of bacteria, yeast or mold will eventually break down the milk and spoil it. Luckily, it is very easy to identify rotten milk using sensory clues.

“Overall, trust your senses,” O’Brien says. “If it doesn’t look right or smell right, it’s probably spoiled.”

He says weird discolorations, curdling and separation all indicate there’s “enough acid being produced by bacteria to make the proteins precipitate.” In other words: Your milk has gone bad.

O’Brien adds that the breakdown of proteins and triglycerides in milk can lead to off-putting flavors that some describe as “soapy, fruity, bitter or rancid baby vomit.” That, too, usually indicates it’s time for your milk and your drain to get acquainted.

The Center for Dairy Research’s Johnson points out an exception to the taste-test rule: “Glass [containers] allow light to penetrate the milk, and this could cause a chemical change to the milk fat, creating an ‘off’ flavor you can taste, but it’s not a safety issue [because] light oxidation didn’t [affect] microbiological quality.”

When all else fails, check your milk with a “simple sniff test,” Holdaway says. She contends that it’s the best and easiest way to determine whether milk is spoiled.

Can you drink expired milk if it smells fine?

This is a trick question! Remember, milk doesn’t have an expiration date, and if it smells fine, it likely hasn’t spoiled or expired. “If milk exhibits any characteristics of spoilage, like an ‘off’ odor, flavor or texture, it should be thrown out,” Holdaway says. “Otherwise, the milk can be consumed with confidence.”

In other words, if it doesn’t stink, it’s safe to drink.

How can you make milk last longer?

Handling habits play a part in how long milk is good for after the sell-by date, so grocers and shoppers can use them to effectively stave off spoilage and buy extra time to enjoy a cold glass.

Shop smart

Anti-spoilage strategies start at the store. O’Brien recommends always making grocery shopping your last errand so milk doesn’t sit in your trunk. Grab the coldest carton with the latest date stamp, keep all the refrigerated items next to one another in the cart and pack them in the same reusable bag at checkout. Your milk is less likely to warm, for instance, if it’s nestled tightly against cold butter instead of that rotisserie chicken you picked up for dinner.

Holdaway recommends adding milk to the shopping cart last and hurrying home to return it to refrigeration. “Milk should not sit out of the refrigerator or cooler for longer than two hours,” she says. “Cut that time down to an hour in the summer if the temperature reaches 90 degrees. After that, bacteria can start to grow and greatly decrease shelf life.”

Handle with care

Shah warns that drinking directly from the carton, leaving milk open to air, not screwing the cap on tightly and returning poured milk to the original container can all introduce bacteria, mold and yeast to your milk and trigger the countdown to destroyed dairy.

Many of the experts’ tips revolve around fridge factors. Most important, you should keep your unit between 34 and 40 degrees, and milk should live in the coldest part of the fridge. Which, Holdaway says, excludes the door—there, milk “will be exposed to fluctuating temperatures [that] cause it to go bad more quickly.”

Keep clean

It’s also important to keep your refrigerator clean and organized. Holdaway advises regularly cleaning coolers or fridges before use and separating milk from foods with strong odors so you don’t lose your ability to taste when milk has gone bad.

“Odors from fruits, vegetables like onions, unclean conditions and/or the smell of a dirty cooler can be easily absorbed and impact the flavor of milk,” she says. “Citrus fruit stored in close proximity to milk is often to blame when ‘chemical-like,’ ‘off’ flavors are detected in the milk.”

Wait to open

Unopened milk lasts longer, so only break the seal when you are ready to use or drink it, O’Brien says.

Switch to a different type of milk

Call this a cheat if you like, but if you can’t manage to drink cow’s milk before it goes bad, consider pouring a different type of milk in your cereal and coffee. There is a whole world of milk alternatives, including dairy-free varieties like oat and almond milk, and aseptic shelf-stable cow’s milk. (Johnson warns that aseptic milk might appear browner or have a “cooked flavor.”) These often last longer in the fridge.

Or give powdered milk a try. “Dried milk powder has a far longer shelf life than liquid milk and does not need to be refrigerated, due to its low moisture content,” Holdaway says. But be warned: Rehydration causes it to taste slightly different, so it might be for cooking instead of drinking.

Freeze the milk

Milk, of course, can be frozen and used later, especially for cooking, but whether this is advisable depends on who you ask. Shah doesn’t recommend freezing milk you intend to drink straight. “It affects the quality and consistency of the product,” he says. “The fat and solids may separate from the water, and it is impossible to get it homogenous again.”

Johnson is inclined to agree. “Freezing could rupture the fat globules and cause an oxidized flavor to develop.” His colleague O’Brien adds, “There is a reason you don’t see a large frozen milk section at the store.”

Holdaway, on the other hand, thinks you can freeze milk just as you can freeze butter or deli meat and that it is a “great way to store it for future use.” But she has a few tips. “Milk will expand when it’s frozen, so be sure to leave room in the container so it won’t burst,” she says. “Thaw [it] in the refrigerator or in cold water. For best results, freeze milk for three to six months, no longer.”

You can freeze plenty of other foods to lengthen usability, and successfully employing freezing and thawing hacks can ultimately save money at the register.

Sources:

• Amit Shah, senior director of quality at Maple Hill Creamery in New York
• Alex O’Brien, food safety and quality coordinator at the University of Wisconsin Center for Dairy Research in Madison
• Julia Joseph, co-founder of Maple Hill Creamery in New York
• Megan Holdaway, RDN, nutrition science manager at the Dairy Council of California
• Mark Johnson, assistant director of the University of Wisconsin Center for Dairy Research in Madison
• Nutrition Today: “Raw Milk Consumption”
• Cornell University: “Pasteurized versus Ultra-Pasteurized Milk – Why Such Long Sell-By Dates?”
• Food and Drug Administration: “How to Cut Food Waste and Maintain Food Safety”