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Milk is an excellent source of calcium and vitamins. However, it’s important to understand its shelf life so you can be sure to consume it when it’s fresh and avoid accidentally ingesting spoiled milk.
Consuming spoiled milk can cause great discomfort, including stomach pain, nausea, diarrhea, and even vomiting. To avoid these health concerns, answering common questions like how long milk can sit out before it goes bad is important.
You might think that milk that has been out of the fridge for any amount of time is spoiled, but it depends on factors like the type of milk and how long it sits. This guide can help you determine how long your whole milk can be left sitting out or whether you should refrigerate almond milk.
What Temperature Should Milk Be Stored At?
Store your milk at the proper temperature to ensure it is fresh and safe to consume. Dairy milk needs to be stored at or below 40°F (4°C) to stop the growth of harmful bacteria. This is also true for many non-dairy milks, such as almond or oat milk, which should always be put in the fridge after opening.
Make sure you check the settings for your refrigerator when storing milk to ensure it stays at the proper temperature to prevent spoiling. If you’re unsure, use a thermometer to double-check and ensure proper storage for your milk.
What Factors Affect Milk Spoilage When Left Out?
Knowing which environmental factors can affect how quickly milk spoils is important. That way, you can prevent early spoilage and correctly identify if your milk has gone bad. Knowing these factors can help you keep your milk safe to consume for as long as possible.
Temperature
As mentioned previously, you should store your milk at a cool temperature of 40°F (4°C) or below. Leaving milk out at higher temperatures for too long can allow harmful bacteria to grow, which can cause it to spoil more quickly.
Exposure to Light
It’s important to avoid leaving your milk out in the sun, as this can degrade its quality and cause it to spoil more quickly. Ultraviolet light from the sun is especially harmful, while artificial lighting will have less of a negative effect. Even so, storing your milk somewhere dark and cool, like the fridge, is key to keeping it fresh and maintaining quality.
Container Type
The type of container your milk is stored in can impact how well the contents are protected from environmental contamination. Dairy milk is commonly sold in plastic jugs, as these are an effective storage method that protects it. Glass containers can also keep milk fresh. However, they are not often used today due to environmental factors and being heavier than plastic jugs. On the other hand, milk in cartons has a shorter shelf life as the paper material does not protect the milk as effectively.
Humidity
You should avoid exposing your milk to high humidity as much as possible. Humid conditions can create an environment for mold and bacteria to flourish, causing your milk to spoil more quickly.
Pasteurization
Unless you buy raw milk, dairy milk has typically been pasteurized. This process kills off most of the harmful bacteria present in milk when it’s first harvested. Pasteurization makes milk safer to consume and extends its shelf life. However, even pasteurized milk must be stored properly to prevent spoiling, especially after opening it.
How Can You Recognize Spoiled Milk?
To avoid accidentally drinking spoiled milk, you should know the signs of what happens to milk when it has gone bad. Recognizing spoiled milk through physical changes other than taste will help you avoid getting sick from accidental consumption.
Sour Smell
Spoiled milk often has a strong, sour smell. If you open your milk container and notice a strange odor, this is likely a sign that it is no longer safe to drink. If you’re ever unsure if milk is still good, try a smell test to check for spoilage. While the off smell will be slightly different for alternatives like oat or almond milk, these will also smell slightly sour when spoiled.
Curdling
As milk goes bad, it can begin to separate into solid and liquid parts. You can often notice solid lumps in milk that have spoiled. If you see any signs of separation in your milk, you should not drink it.
Change in Texture
When going bad, milk often changes texture. Specifically, it may get thicker or even appear slimy. If you drink oat or almond milk, a clumpy texture can be a sign that this non-dairy milk has gone bad as well. If you notice these physical signs with your milk, it should be thrown away and not consumed.
Color Change
As milk spoils, it can develop a yellowish hue. If you notice signs of yellowing in your dairy milk, this likely means it has begun to spoil. Oat milk will also change color when it goes bad, so if it seems yellower than usual, you should throw it away.
Mold
If you see blue, green, or black spots in your milk or on the container, that’s a likely sign that mold is present. You should immediately discard any milk that has been exposed to mold, as it is not safe to consume.
What are the Health Risks of Consuming Spoiled Milk?
Consuming spoiled milk can have various adverse health effects you want to avoid. In cases of a small accidental sip, the illness may be mild. However, there can be some more severe health effects if spoiled milk is consumed in larger quantities or over a long period.
Food Poisoning
Spoiled milk can cause food poisoning. While there are often no long-term health impacts from food poisoning, it can be incredibly uncomfortable. Food poisoning from spoiled milk can cause nausea, vomiting, and diarrhea that can last up to 24 hours.
Fever
If you consume spoiled milk containing bacteria, you may run a fever. This is part of your body’s response to harmful bacteria being introduced through spoiled milk.
Infection
If your body does not fight off the harmful bacteria present in spoiled milk, you may wind up with an infection such as E. coli or Salmonella. In particular, gastrointestinal infections may result from consuming milk that has gone bad.
Weakness and Fatigue
Food poisoning and possible infection from ingesting spoiled milk can cause weakness and fatigue. As your body fights off infection from harmful bacteria, you may struggle to complete daily activities due to low energy and general feelings of weakness.
Does Pasteurized Milk Spoil Slower Than Raw Milk?
Pasteurization removes most of the bacteria in milk when it’s first harvested. Since it starts out with a much lower microbial load, pasteurized milk tends to spoil more slowly.
On the other hand, raw milk is not pasteurized, which means it retains more bacteria. This causes raw milk to spoil more quickly since more bacteria will be present when you buy this form of milk.
Bottom Line
If you’ve ever wondered how long milk can sit out before going bad, this guide proves the importance of keeping dairy milk and milk alternatives in the fridge. Keeping your milk at the right temperature and in a proper container will extend its shelf life. Buying pasteurized milk rather than raw milk can also ensure that your milk has a longer shelf life and stays safe to consume.
It’s also important to stay alert for signs that your milk has begun to spoil so you can avoid the negative health impacts of consuming spoiled milk. Store your dairy milk or milk alternative in the fridge in a sealed container to ensure it stays fresh for longer and is safe to drink when you need it.
