How Long Does Milk Last? (Opened vs. Unopened)

We’ve all been there: holding the milk carton, squinting at the date, and giving it a tentative sniff. Milk spoilage is one of the most common kitchen annoyances, but understanding the “Use By” vs. “Sell By” dates—and how to store it properly—can save you from a chunky cereal disaster.

Shelf Life Overview

Milk is highly perishable. Here is the breakdown based on USDA data:

• Opened Milk: Lasts 5–7 days in the fridge.
• Unopened UHT (Shelf-Stable) Milk: Lasts 6–12 months in the pantry (check the date).
• Opened UHT Milk: Lasts 5–7 days in the fridge (same as fresh milk!).
• Freezer: Can be frozen for up to 3 months (90 days).

Note: “Lactose-free” or ultra-pasteurized milks often last longer (up to 70-90 days unopened), but once opened, the 7-day rule still applies!

How to Tell if Milk is Bad

Your nose knows. But here are the specific signs:

• Smell: A sour, tangy, or “off” odor is the first sign. Fresh milk smells sweet and creamy.
• Texture: If it pours with chunks or looks curdled (lumpy), it’s gone. Do not drink it.
• Container: A swollen or bulging carton indicates bacteria are producing gas inside.

Storage Tips to Keep it Fresh

• The Door is a No-Go: Never store milk in the fridge door. It’s the warmest part of the fridge. Keep it on a shelf in the main body where the temperature is stable (below 40°F).
• Close it Quick: Don’t leave the carton on the counter during breakfast. Pour what you need and put it back immediately.
• Keep it Dark: Light destroys riboflavin (Vitamin B2) in milk and can affect the flavor.

Can You Freeze It?

Yes, but with a catch.

Milk freezes safely for 3 months, but it will likely separate and become grainy upon thawing.

• How to use: Thawed milk is fine for cooking, baking, or smoothies, but you probably won’t enjoy drinking it straight.
• Tip: Pour a little out before freezing, as liquids expand when frozen and could burst the jug.

Frequently Asked Questions

How long is milk good for after opening?

Standard pasteurized milk is usually good for 5-7 days after opening. Trust your nose!

How long past the expiration date is milk good for?

If unopened and stored properly, it can last 5-7 days past the printed date. Once opened, the clock starts ticking regardless of the date.

Can you freeze milk?

Yes, but the texture changes and it may separate. It is best used for cooking or baking rather than drinking.

Can cats drink milk?

Contrary to popular belief, most adult cats are lactose intolerant. Cow’s milk can cause stomach upset. Stick to water.

Can I use sour milk in baking?

If it’s slightly sour but not curdled or moldy, it can be a great substitute for buttermilk in pancakes or biscuits.