Why Milk Spoil Even When Refrigerated? (5 Reasons You Should Know)

Milk is an essential component of many people’s diets. 

It is a complete food containing water, fats, proteins, vitamins, and minerals. However, the mix of nutrients and a pH of around seven make it an ideal growth material for many microbes. 

Milk is a perishable item and is not consumable after been kept for an extended period, so it needs to be stored properly to keep it drinkable.

Many people believe that once they buy milk and put it in the refrigerator, they can use it. However, that is not entirely true, and many factors determine the shelf life of the milk. 

Milk can also spoil even if it is kept in a refrigerator. Once it begins to sour, no preservative measure can bring it back to normal. What a fridge can do is to delay milk spoiling. 

Here are the five reasons why milk will still spoil even if it is refrigerated. 

why does milk spoil even when refrigerated?

The temperature of the location where milk is kept in the fridge

When it comes to milk, the temperature is an essential factor, and most of the time, the milk gets spoiled when adequate temperate is not maintained inside the refrigerator.

Also, keeping milk anywhere in the refrigerator is not a good idea as it will spoil at some point. 

The place you keep the milk matters a lot; certain temperature conditions favor different types of milk, but there is a standard. 

To restrict bacteria from growing on refrigerated food and milk from spoiling, the USDA recommends that such food items be stored at temperatures below 40 degrees Fahrenheit. 

This means that any food stored at a higher temperature is at risk of spoiling. For milk, it is better to store between 35-40 degrees Fahrenheit.

This is the only way your milk can stay in the refrigerator without getting spoilt.

Note that if it is stored for too long, it might lose its quality and eventually spoil.

The container used to store milk

The type of container used and its coverage influences the milk’s quality when stored in the refrigerator. 

Using an unclean container to store milk will spoil the milk quickly.

It is better to store your milk in glass containers as you place them in the fridge; this is because it does not contaminate the milk as it is non-porous. 

Glass bottles can remain cold for a certain amount of time longer than plastics in case there is a power outage.  

Amount of time milk spends in and out of the refrigerator

If your milk spends more time outside than it spends in the refrigerator at the required temperature, it will spoil. 

Most people leave the milk out on the kitchen table till breakfast is over, and then they forget to put it back in the fridge.

Leaving the milk in the room temperature for a longer time and then placing it in the refrigerator is one of the most common reasons why milk spoils even when refrigerated.

The best practice is to place the milk back in the refrigerator immediately after using it. This way, you can extend the expiry time of the milk.

Method of production

The production method will also determine the amount of time it will take the milk to spoil even if it remains in the refrigerator. 

There are three primary milk production methods, namely, Pasteurization, Sterilization, UHT milk. 

In general, pasteurized milk last longer and remains good up to 10 days when properly refrigerated.

Psychrophilic bacteria

Psychrophilic is a kind of bacteria that is known to duel in cold temperatures.

It performs better when within the cold temperature and can develop on the milk while in the refrigerator.  

Immediately the bacteria act on the milk. It begins to sour and eventually spoils. 

The best way to prevent this bacterium from acting on your milk is to ensure that your fridge has a stable temperature and does not carry out a massive change in temperature because changes in temperature trigger the bacteria.