Pasteurized Milk

Milk is considered as one of the most nutritional, natural, liquid food. It is rich in high quality protein, essential minerals, and vitamins that are beneficial for human health. Along with all these essential nutrients, milk also contains a number of micro-organisms.

Most of these bacteria are harmless; in fact, some are even beneficial. However, several factors such as the health of the animal, improper handling, pollutants from air and water, etc., can contaminate raw milk and make it unfit for consumption.

Raw milk can be contaminated by pathogens such as Salmonella, Escherichia coli, Listeria monocytogenes, Yersinia enterocolitica, Campylobacter jejuni, Staphylococcus aureus, and many more. All these micro-organisms can be harmful to us in some way or the other.

Several pathogens find their way into milk and multiply, since its nutritional components support their growth well. This brings us to the technique of pasteurization which is used to kill all these pathogens.

Pasteurization is a technique of heat-treating milk to destroy all the pathogens present in it. This process was named after its creator, Louis Pasteur, a French chemist and microbiologist. He was the first one to perform this procedure, and successfully eliminate most of the disease causing bacteria. Pasteurization does not alter the taste of milk and retains all the milk health benefits.

Milk is generally heated to 161ºF for 15 seconds to kill the micro-organisms. There are several methods of pasteurization including high temperature-short time pasteurization, low temperature-long time pasteurization, flash pasteurization, steam pasteurization, irradiation pasteurization, and ultra-high temperature pasteurization.

Given below is the procedure to pasteurize milk at home.

Procedure:

1. Place raw milk in a double boiler. You can use a stainless steel pot if you do not have a double boiler.
2. Place this pot containing raw milk into a larger pot with a few inches of water.
3. Heat the milk slowly to 145º.

4. Stir constantly to avoid scalding the milk. Maintain this temperature for exactly 30 minutes.
5. Remove the pot from the heat, and cool it by placing in a large bowl filled with ice water.
6. Stir frequently, until the temperature drops to 40º.
7. Store it in a refrigerator.

It is important to note that improper handling may recontaminate the milk. You need to refrigerate the milk to prevent it from spoiling.

A lot has been said about the nutritional content of pasteurized milk. It is believed that this process reduces its nutritional value. However, the nutrients are almost similar to those present in raw milk. Although heating at high temperatures does break down some of its components, the effect on nutrition is only marginal.

Pasteurized milk is also said to cause lactose intolerance. However, lactose is a substance that occurs naturally in milk, and pasteurization does not have any effect on the levels of lactose. Both the types can cause equal allergic reactions in those who are sensitive to milk proteins. This is because they have the same lactose content.

Pasteurization limits fermentation, and increases shelf life. However, not all pathogens are destroyed by this process, and hence, the milk isn't 100% sterile.