If you've ever shopped for milk, you've no doubt noticed what our questioner has: While regular milk expires within about a week or sooner, organic milk lasts much longer—as long as a month.
Long life milk can be stored for up to six months in a pantry, but once opened it needs to be refrigerated. Then it can be used normally like fresh milk within seven days. You might also see long life milk referred to as "ultra heat treatment (UHT)" milk.
The combination of UHT ultra-pasteurization and shelf-stable packaging eliminates the need for refrigeration and prevents spoilage without the use of preservatives. This gives the milk an amazing shelf-life of 6 to 9 months!
We took the question to UAMS Director of Nutrition Tonya Johnson, who said that chocolate milk and whole milk actually tend to have a longer shelf life. The sugar in chocolate milk reduces the growth of bacteria and, typically, the higher the fat content, the longer it takes milk to spoil.
For shelf-stable milk, we use UHT, or Ultra High Temperature, pasteurization. This process heats milk to a very high temperature for a few seconds, which destroys bacteria for a longer shelf life.
Milk can often be consumed after its expiration date, generally for up to three days for opened milk and up to seven days for unopened milk. Before consuming, it's best to look for signs of spoilage. You can tell if milk is bad by checking the smell, color, consistency and taste.
After opening, most milk manufacturers recommend drinking the milk at or within 7 days. This assumes the milk didn't have any bacterial contamination after opening and is stored in temperatures of below 40 degrees Fahrenheit.
How long it stays fresh depends on how it's treated. Most supermarket milk has been pasteurized and if unopened can keep in the fridge for around a week. Milk that is heated to temperatures above 135ºC (275 °F) can keep as long as six months at room temperature if unopened.
Aseptic milk will stay good in your pantry for up to six months. However, once you open it, it must be refrigerated immediately. Aseptic milk is best enjoyed within seven days of opening.
Shelf stable milk (UHT milk) can be stored unopened and unrefrigerated for about three months. Be sure to read the label as this can vary by brand. Once the container is opened, shelf stable milk should be refrigerated in an airtight container and has the same shelf life as fresh milk (seven to ten days).
Opened UHT and canned milk must therefore be refrigerated. After opening canned milk, immediately transfer any unused portions to a clean, opaque and airtight container. These milk products should be used within 3 days of opening. If stored in a cool, dry place, powdered milk will keep for up to 6 months.
Freezing milk is easy, helps avoid waste, allows a backup supply, and saves money. Thawed milk will be most nutritious if people freeze it at its freshest. However, as long as freezing happens on or before the best before date, it is fine to freeze milk and thaw it for later use.
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.
Milk can stay safe to consume for several days past the expiration date. Expiration dates on food and drink products relate to their quality rather than their safety. Drinking spoiled milk can make people unwell, but it is typically easy to tell when milk is bad.
Your sense of smell and taste are your best friends here, and they'll give you the best indication of whether the milk is ok to drink – if it doesn't smell, look strange (lumpy or separated), and it tastes just fine, then you're okay to drink it.
Skim milk was found to spoil slightly faster, but the researchers weren't exactly sure why. Psychrotrophic, or cold-resistant, bacteria are what cause spoilage in the fridge, and they multiplied at the same rate in both types of milk. When the milk spoiled, both whole and skim contained similar strains of bacteria.
Tips for preserving your milk for longer
Regarding milk, she advises: “Transfer milk to glass bottles. It will last twice as long. Glass gets and stays much colder than cardboard. Also, glass bottles are better sealed than cardboard containers, so they don't let as much air in.
In general, perishable foods like milk should not sit out of the refrigerator or cooler for longer than two hours. Cut that time down to an hour in the summer if the temperature reaches 90 degrees F. After that time frame, bacteria can start to grow.
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.
Freshly expressed or pumped milk can be stored: At room temperature (77°F or colder) for up to 4 hours. In the refrigerator for up to 4 days. In the freezer for about 6 months is best; up to 12 months is acceptable.
According to the US Department of Agriculture, milk and other dairy products should be kept in the refrigerator at or, ideally, below 40°F. If the temperature gets higher than that, bacteria can start to grow in the milk, which is what causes the rotting and the smell.
Shelf-stable (aseptic) milk is milk that does not need to be refrigerated and can be stored at room temperature in your pantry for later use, says Julia Joseph, co-founder of Maple Hill Creamery.
The nutritional value of UHT milk and fresh milk are the same when it comes to the main nutrients in milk, such as protein, calcium and Vitamin D. UHT treatment may reduce the level of some heat sensitive nutrients such as vitamin C, but milk is not the main source of these nutrients in the first place.