Differences Between Pasteurized Milk And UHT Milk

Both processes aim to increase the shelf life of the milk as well as its hygienic safety. They do, however, have some differences. Do you want to know them?

Do you know the differences between pasteurized milk and UHT milk? Pasteurization and superification are sterilization treatments that are used to increase the shelf life of milk. Both also destroy pathogenic microorganisms that can live there and harm humans.

On the other hand, both of these methods involve heating the milk for a period of time before cooling it down and bottling it. However, there are differences in both heating times and organoleptic and nutritional changes.

In any case, these are sterilization methods that are not only used in the dairy industry. They are also common in breweries and the can factory. 

What makes pasteurized milk different from UHT milk?

Pasteurization

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

It therefore respects a good part of the natural flora of the product. However, this flora is able to spoil the milk in a short time. Therefore,  it is advisable to keep the product in a cool place even if it is not yet opened.

UHT milk

This is a more aggressive heat treatment. On the one hand, we have the UHT milk which is heated by injecting water vapor and then quickly cooled. On the other hand,  there is UHT milk which is subjected to temperatures of 138 ° C for a few seconds.

There is a hypothesis according to which this type of treatment could lead to the production of waste harmful to health. However, it has been proven to be harmless. This is what an article published in the “ European Journal of Clinical Nutrition ” affirms .

This thermal process is continuous flow and the contact is direct. This  results in minimal deterioration of the milk and allows it to be kept in perfect condition even at room temperature. However, it should be consumed within a maximum of 3 days once opened.

Moreover, this treatment makes it possible to destroy the pathogenic organisms, but also the spore-forming forms. That said,  it is a relatively recent sterilization technique.

In fact, from a technological point of view, the industry has faced two problems. First, the way to quickly heat and then cool the milk. Second, how to find a sterile container for its storage. The first problem was solved by applying steam and pressure variations. And the second with the invention of the tetra brik .

Influence on nutritional properties

During pasteurization there is hardly any change. During storage,  there may be a loss of photosensitive vitamins. This is the case with vitamin A or riboflavin.

However, it is different for UHT milk. As this is a more aggressive treatment from a thermal point of view, there is a loss of vitamins.  Levels of ascorbic acid and vitamins B1 and B12 decrease.

On the other hand, during prolonged storage, there may also be the loss of other vitamins such as A and B6. Proteins and amino acids are unchanged in both processes.

In any case, these sterilization processes have allowed greater marketing and better access to milk in households, in terms of safety and quality. Sterilization effectively improves the preservation of the product and reduces its microbiological risks.

On the other hand, in recent years, the influence of the consumption of UHT milk on the intestinal microflora has been studied. It seems that no significant effect has been observed, according to this article published in the magazine “ Nutrients ”.

Although they do not reach level A evidence, the findings speak to the fact that  consumption of milk changes flora and increases inflammation. It is therefore preferable to consume fresh milk instead of UHT milk.

Pasteurized milk and UHT milk, two healthy foods

Both processes serve to increase the shelf life of milk and also increase its hygienic safety. However, there are a number of differences:

• Pasteurized milk should always be kept cool. While UHT milk  can remain at room temperature  until the bottle is opened.
• The expiration date of pasteurized milk is 4 days from bottling. Whereas UHT milk can be stored for months.
• Pasteurized milk has organoleptic characteristics very similar to those of raw milk in terms of smell, flavor and color. This is because it is subjected to a lower temperature than UHT milk.