How long is eggnog good after opening, or after the date on the carton?

Why the carton date can be weeks away

Eggnog sold in the US has a federal recipe. It must contain milk or cream, egg yolk (at least 1 percent egg yolk solids by weight) and a sweetener, and it “shall be pasteurized or ultra-pasteurized.” If it is ultra-pasteurized, the word has to appear next to the name on the carton, so look for ultra-pasteurized near the word eggnog.

Ultra-pasteurized dairy is heated to at least 280°F for at least 2 seconds, which federal rules describe as producing “a product which has an extended shelf life under refrigerated conditions.” That's how a carton can carry a date weeks after the day you buy it. The long life applies to the sealed carton. For ultra-pasteurized milk, a close cousin, FoodKeeper gives 1–3 months unopened but only 7–10 days once opened. It doesn't split eggnog that way; it lists one time, 3–5 days from purchase.

What the date on the carton means

Except for infant formula, no federal rule requires a date on food, so the dairy picks both the date and the phrase. USDA describes a use-by date as “the last date recommended for the use of the product while at peak quality,” and a sell-by date as a date for the store's display, not a safety date. Some cartons show both; see two dates on one label for which one to follow.

USDA also says that, in general, food that passes its date at home should still be wholesome if it was handled properly, until spoilage shows. For eggnog, though, USDA's own storage time is short, and we found no federal source that gives any number of days past the carton date.

Opened vs. unopened

At a party, pour eggnog into a pitcher in small batches and put the carton back in the fridge. A carton that sat on the buffet table all evening has passed the 2-hour mark and should go, whatever the date says. If you're not sure how long it sat out, throw it out.

FoodKeeper has no entry for plant-based or shelf-stable nogs, so follow the storage directions on the package for those.

The carton date is easy to lose behind the leftovers. Scan it when you unpack and FreshScan reminds you at 9:00 AM two days before. If the carton shows both a sell-by and a use-by date, the app lists both and asks which one to track. You can also type in a date yourself, such as the day an opened carton should be finished.

Free on theApp Store

Homemade eggnog: make the eggs safe first

Raw eggs can carry Salmonella, and USDA advises against eggnog made with egg ingredients that aren't thoroughly cooked. There are two safe routes:

• Use pasteurized eggs or egg products. USDA recommends them for any recipe that calls for raw or undercooked eggs. FDA notes that pasteurized eggs in the shell are sold in the refrigerated section.
• Cook the egg base to 160°F. USDA says egg mixtures are safe once they reach 160°F, so eggnog can be made safely from a cooked egg and milk mixture. FDA's recipe whisks hot milk into beaten eggs and sugar, then cooks the mixture over medium-low heat, whisking constantly, until it thickens, just coats a spoon and a food thermometer reads 160°F (71°C). It is cooled quickly in a bowl of ice water, chilled for several hours, and the whipped cream goes in just before serving.

Either way, homemade eggnog keeps 2 to 4 days in the fridge, according to USDA's egg storage chart, which also says not to freeze it. Keep it covered in the fridge. If you need more than a few days' worth, make a second batch later instead of one big one.

Does alcohol make raw-egg eggnog safe?

No, not reliably. An FDA food technologist has warned that if contaminated, unpasteurized eggs are used, “you can't count on the alcohol in the drink to kill all of the bacteria.” NC State food safety researcher Ben Chapman points to a 2010 study in which ethanol reduced Salmonella only partly over 24 hours, with no reduction in the first hour, and notes that the fat in cream can protect the bacteria. He calls the well-known story of aged, spiked eggnog from a university lab anecdotal, and notes that it wasn't peer reviewed. If you add alcohol, start with pasteurized eggs or a cooked base anyway.

Freezing eggnog

Store-bought eggnog keeps 6 months in the freezer. FDA's storage chart explains that freezer times are for quality only, because food kept at 0°F (-18°C) stays safe. FoodKeeper counts that time from the day you buy the carton.

Thaw it in the refrigerator, not on the counter. NDSU Extension notes that frozen milk can change in quality after thawing and that stirring or shaking may help restore smoothness; eggnog, being mostly milk and cream, may separate the same way. It also advises not to refreeze thawed dairy. Don't freeze homemade eggnog.

Signs eggnog has gone bad

USDA says spoiled foods develop an off odor, flavor or texture, and FDA suggests avoiding products that have changed noticeably in color, consistency or texture. With eggnog, throw it out if you notice:

• A sour or otherwise off smell when you open the carton.
• Lumps, curdling, or a thick, slimy texture.
• A change in color.

These signs are reasons to throw eggnog out, not a test that proves it's fine. USDA separates the spoilage bacteria that cause off smells from the pathogenic bacteria that cause illness, and the second kind doesn't announce itself. Don't taste eggnog to decide. When in doubt, throw it out.

For the rest of the holiday fridge, see how long milk keeps, heavy cream and Thanksgiving leftovers. The shelf life chart lists USDA times for other foods, and the food expiration calculator turns the day you bought a carton into a date range.

Questions people ask