It is common practice for us to boil a glass of milk before having it. Did you know that this practice has its origins in Chemistry and the benefits of which was first discovered by the French chemist Louis Pasteur.
We all enjoy a healthy glass of milk. It gives us protein, minerals and vitamins that are essential for our diet. For a long time people used to get sick due to various harmful bacteria present in raw milk. Such food borne diseases were common. One of the most common diseases that you can get from raw milk is Salmonella poisoning which causes vomiting and diarrhea.
In 1864, Louis Pasteur discovered heating liquids to a temperature slightly below boiling for a certain time, can eliminate harmful bacteria.
In 1864, Louis Pasteur discovered that by heating liquids like milk to a temperature that was slightly below boiling and keeping it at this temperature for a certain time, you could eliminate harmful bacteria. It was for this contribution, that the process has been named after him.
How pasteurization works
This works on the basic principle that most harmful bacteria can be killed by the application of heat. If you were to constantly boil the milk, though it would kill all the bacteria present, it would lose some of the taste and reduce its nutritional value; pasteurization of milk does not face this problem.
How milk is pasteurized
Milk is pasteurized at temperatures that are below boiling point. Ideally this is done at a temperature of 62.8°C for half an hour. If you can’t wait that long you can also heat the milk to 72.8°C for 15 seconds, this is known as flash pasteurization and will sterilize the milk. Flash pasteurization is popular for fruit juices. It is very likely that the juice you bought last time in a tetra pack was Flash pasteurized. Remember that pasteurization only kills harmful bacteria. It does not kill all the bacteria present in the liquid.
How to handle large amounts of milk
But wait a minute. How would you pasteurize a large quantity of milk? Think of the number of vessels and stoves you would need to pasteurize the amount of milk your town or city needs! It is for this reason that milk can also be pasteurized using a continuous system or a batch system. In a continuous system, milk flows through a pasteurization system continuously. This is used when a large quantity of milk needs to be pasteurized. Batch pasteurization is what you do at home. Pasteurize small quantities at a time. Remember that you need to store pasteurized milk carefully to ensure no bacteria enter it.e benefits of pasteurization
Pasteurization not only makes liquids like milk safe for you to eat, but improves its shelf life. What this means is that if you pasteurize milk, it will last longer and not get easily spoiled like ordinary milk. Once milk is pasteurized it needs to be refrigerated to ensure it does not spoil. Usually pasteurized milk will last two to three weeks.