Pasteurized Milk And UHT Milk – Learn About The Differences Between Them

Do you know if pasteurized milk is different from UHT milk? Both pasteurization and uperization are sterilization methods that serve to extend the shelf life of milk. In addition, they destroy pathogenic microorganisms that can live in it and cause harm to people.

Both methods involve heating the milk for a specified period of time, then cooling it and packing it. However, pasteurized milk and UHT milk show differences both in heating time and in changes in organoleptic and nutritional properties.

However, these are sterilization methods used not only in the dairy industry. They are commonly used in the brewing industry and in the production of many cans, canned as well, such as packaged sausages.

How is pasteurized milk different from UHT milk?

Pasteurization

The result is fresh milk. This is the process by which the milk is heated to a temperature between 55 and 75 ° C for 17 seconds. This process helps to eliminate pathogenic bacteria while maintaining the quality and natural properties of the product.

Thus, pasteurization maintains a significant part of the natural bacterial flora of milk. However, this flora is able to make the milk squirt in a short time. For this reason, it is recommended to store pasteurized milk at a low temperature, even if the container has not yet been opened.

Moreover, its use-by date usually does not exceed a few days.

UHT milk

For UHT milk, a more aggressive heat treatment is used. In this category, on the one hand, we have perized milk, which is heated by steam injection and then quickly cooled. On the other hand, we have UHT milk, which is subjected to a temperature of 138 ºC for a few seconds.

It has been speculated that this type of treatment may lead to the formation of harmful waste products. However, over time, the safety of products subjected to such treatment has been proven. This is stated in an article published in the European Journal of Clinical Nutrition .

This thermal process uses continuous flow and direct contact, resulting in minimal product variation. The process then keeps it in perfect condition even at room temperature. However, it should be consumed within a maximum of 3 days from opening.

Such a procedure allows for the destruction of pathogenic organisms, as well as sporulated forms. However, this is a relatively new method of sterilization.

This is due to the fact that, technologically, the industry has encountered two problems. First, how to quickly heat up and cool down milk. Secondly, how to find a sterile and leak-proof container for its maintenance. The first problem was solved by the use of steam and pressure variations, and the second by the invention of the tetra Brik.

Effect on nutritional properties

There are practically no changes to the product during pasteurization. However, during storage, photosensitive vitamins such as vitamin A or riboflavin may be lost.

However, the situation is changing with UHT milk. As it is a more aggressive procedure from a thermal point of view, there is a loss of vitamins. The level of ascorbic acid and vitamins B1 and B12 decreases.

In addition, other vitamins such as A and B6 may be lost during long-term storage. Proteins and amino acids, on the other hand, will remain unchanged in both thermal processes.

In any case, thanks to these sterilization processes, milk reaches homes as a safer and better quality product. The shelf life of the product is improved and its microbiological risk is reduced.

Meanwhile, in recent years, the impact of UHT milk consumption on the intestinal microflora has been studied. No significant effects were found, according to an article in the journal Nutrients .

The conclusions, although not reaching the evidence level A, say that consumption of this milk modifies the flora and increases inflammation in the body. Therefore, it is recommended to give priority to fresh milk over UHT milk.

UHT and pasteurized milk, two good products

Both processes serve to extend the shelf-life of milk and increase its sanitary safety. However, they present a number of differences:

• Pasteurized milk should always be kept chilled , however UHT milk may remain at room temperature until the container is opened.
• The shelf life of pasteurized milk is 4 days from packing, while UHT milk is stored for months.
• Pasteurized milk has organoleptic properties more similar to raw milk in terms of smell, taste and color. This is because it has been subjected to a lower temperature than UHT milk.