What is in milk to make it last longer?

There are several substances in milk that can help to extend its shelf life.

* Lactic acid: Lactic acid is produced by bacteria that naturally occur in milk. It helps to lower the pH of milk, which inhibits the growth of other bacteria that can cause spoilage.

* Casein: Casein is a protein that makes up about 80% of the protein in milk. It forms a protective layer around fat globules in milk, which helps to prevent them from breaking down and causing the milk to spoil.

* Lactoferrin: Lactoferrin is a protein that helps to bind iron in milk. It has antimicrobial properties that can help to inhibit the growth of bacteria.

* Immunoglobulins: Immunoglobulins are proteins that help to protect the body from infection. They are present in milk and can help to inhibit the growth of bacteria.

In addition to these natural substances, some milk products also contain added preservatives that can help to extend their shelf life. These preservatives can include:

* Potassium sorbate: Potassium sorbate is a common preservative that is added to many foods, including milk. It is an antifungal agent that helps to prevent the growth of mold and yeast.

* Sodium benzoate: Sodium benzoate is another common preservative that is added to many foods, including milk. It is an antibacterial agent that helps to prevent the growth of bacteria.

By combining natural preservatives and added preservatives, milk can be made to last for several weeks or even months at room temperature.