How fast does milk spoil?

In this brief guide, we are going to answer the question “how fast does milk spoil” with an in-depth analysis of the time it takes for milk to spoil and different ways to spot spoiled milk. Moreover, we are going to discuss the health implications of drinking spoiled milk.

So without much ado, let’s dive in and figure out more about it.

How fast does milk spoil?

Open milk whether it be whole milk, skim milk, or reduced-fat milk stays for about 4 to 7 days before getting spoiled when stored in the fridge at or below 40 degrees Fahrenheit in an air-tight container or bottle. 

On the other hand, the unopened whole milk lasts for about 5-7 days,  reduced-fat and skim milk for 7 days while non-fat and lactose-free milk for 7-10 days past the printed date on it provided that it is stored properly in the fridge at or below 40 degrees Fahrenheit.

Last but not least, open milk lasts for about 2 hours before getting spoiled when left out at room temperature.

You should discard the milk that has been left in open for more than 2 hours as bacterial growth takes place at a faster pace between the temperature of 40 and 140 degrees Fahrenheit, therefore there are greater chances of the milk being already contaminated with bacteria when left out for more than 2 hours.

It is worth mentioning that these figures are just the estimated shelf life of the milk and you should do a sensory evaluation of the milk to reach a final verdict on whether or not it is still suitable to consume.

There are a couple of indicators that point out spoiled milk. You should consider the appearance, texture, smell, and taste of the milk to give a final verdict of whether or not it has spoiled.


If you spot a mold or any other organic growth in your milk carton (it is a really rare phenomenon), then the best thing you can do is to get rid of this milk as it is an indication of spoiled milk.


If the milk is curdled or has lumps present in it, then it is an indication of spoiled milk and you should get rid of it.


If you smell something foul or sour while taking a sniff test then it is an indication that the milk has spoiled and the best thing to do is to discard it.


If the milk has passed the visual and smell test, then you can go ahead and taste it. If you notice a sour or slightly bitter taste after taking a little sip of milk then it is an indication that the milk has spoiled. 

If microbes somehow found their way to your milk and have spoiled it then the best thing you should do is to discard it.

Health implications of drinking spoiled milk

If you have devoured milk that has spoiled, it can result in food poisoning that is characterized by nausea, vomiting, diarrhea, abdominal cramps, fever, weakness, headaches, and dehydration.

A mild food poisoning lasts for about a day or two while a more persistent case of food poisoning can last for about 10 days.

So in case you have devoured spoiled milk and are now suffering from vomiting and diarrhea,  you should try to drink as much water as possible so that while the body is getting rid of the toxins in form of diarrhea and vomiting, the water that you drink will protect your body against dehydration that vomiting can otherwise result in. 

In case the symptoms worsen, or diarrhea and vomiting persist for more than 3 days you should seek medical help.

You can read about different types of microorganisms and their activity in milk here.

Other FAQs about Milk which you may be interested in.

Can you drink milk 2 days after the expiration date?

Does coconut milk thicken when heated?

Is milk safe to use after the best-before date?

The “best by” or “best before” date that is written on the carton of milk refers to the quality rather than safety so the milk doesn’t necessarily go spoiled immediately after the best before date. 

It is the time during which you can enjoy the peak quality and flavor of milk but you can still use milk that is past this date as long as it was stored properly, there is no leakage in the carton and no signs of spoilage are associated with it.

Benefits of milk

Milk is a food product that is considered a complete meal in terms that it has an appropriate ratio of all the nutrients, including carbohydrates, proteins, fats, vitamins, and minerals.

The most important sugar is lactose that can be problematic in many people due to the problems of digesting this sugar. The major constituent that is naturally present in milk is water, comprising about 87% of the milk.

Milk is a food that is dense in different nutrients required for the proper growth and development of an individual. It means that one can have all the nutrients to meet the needs by consuming this food product in a daily diet.

Milk is also known to contain a lot of quality proteins that contain almost all the essential amino acids required for proper health. These amino acids can help in the building of muscle mass of the body throughout life, thus reducing age-related muscle loss and promoting muscle repair.

Different micronutrients, such as calcium, vitamin D, magnesium, and phosphorus are also present in enough amounts in milk and provide support to bone health. By supplementing the daily intake with milk, one can prevent the problems of osteoporosis and fractures caused by weak bones.


In this brief guide, we answered the question “how fast does milk spoil” with an in-depth analysis of the time it takes for milk to spoil and different ways to spot spoiled milk. Moreover, we discussed the health implications of drinking spoiled milk.


Mahnoor Asghar is a Clinical Nutritionist with a bachelor's degree in Nutrition and Dietetics. She is compassionate and dedicated to playing her part in the well-being of the masses. She wants to play a fruitful role in creating nutrition and health-related awareness among the general public. Additionally, she has a keen eye for detail and loves to create content related to food, nutrition, health, and wellness.