Pasteurization is a physical process based on the heat treatment of liquid and solid foods to substantially reduce their microbiological load by controlling temperature and time. This technique allows the elimination of microorganisms that cause food spoilage or are a problem for food safety.
The main objective of pasteurization is the substantial reduction of the populations of microorganisms existing in the product. Unlike sterilization, the total elimination of microorganisms and spores is not achieved.
Pasteurization consists of heating a food to temperatures below 100ºC for a few minutes or seconds, and then rapidly cooling it. Times and temperatures vary according to:
The type of product
The most representative factor of a food and that plays a fundamental role in determining the survival of a microorganism is acidity, that is, pH. Pasteurization is especially advantageous to use in foods with low pH since, generally, bacteria grow with difficulties below a pH of 4.5, thanks to this the heat treatment can be softer and the organoleptic characteristics are not so visible. affected.
This method is used mainly in juices and flavored drinks, since the low temperatures allow the aromas not to volatilize too much.
The physical form of the food
The outer surface of the product also influences the heat treatment to be used, if we work with low temperatures and short processes, achieving a high temperature throughout the food is essential, which is why spherical foods are the most difficult to pasteurize.
The type of packaging
The container also plays an important role when it comes to preserving food. The material with which it is made, its porosity, shape and morphology of the closure are decisive to guarantee the quality and useful life of the product, avoiding its possible subsequent oxidation. You will find more information about the different types of containers suitable for pasteurization and sterilization on our Blog.
Pasteurization to avoid altering the product
Thanks to the exact control of temperature and time, both the taste and the smell and the nutritional properties remain little altered. It is essential to correctly apply the temperature and time parameters because not doing so can lead to the survival of microorganisms that can affect human health. Or also the reduction of the nutritional value of the food, in the case that a higher temperature is used for longer than recommended.
Pasteurized foods keep for a few days, two to three weeks, and require refrigeration because, although a good part of the microorganisms are destroyed, a part will remain alive in the food, which over time will grow and cause physical and chemical changes. Likewise, once opened they should be consumed shortly.
Difference between pasteurization and sterilization
Pasteurization and sterilization are often confused. Both methods are used to kill microorganisms with the application of heat to food placed in airtight containers. Its main difference is that sterilization seeks to eliminate any form of life from a food and, on the other hand, pasteurization substantially reduces the microbiological load but does not eliminate it completely. The useful life of the final product and the temperature used in the process are also different. For more information, we advise you to read our post What is the difference between sterilization and pasteurization?
LTLT (Low Temperature Long Time) pasteurization process or slow pasteurization
It consists of heating large amounts of liquid in a container at low temperatures for a long time, and then allowing it to cool. When finished, it should be packed immediately to prevent contamination.
With a TERRA Food-Tech® autoclave the final product can be pasteurized directly in a container.
HTST (High Temperature / Short Time) pasteurization process or continuous pasteurization
It is used to heat bulk liquids quickly to high temperatures and for a short time.
UHT (Ultra-High Temperature) pasteurization process
Although this method is known as ultra pasteurization, it is actually more similar to sterilization since it uses a temperature above 100ºC and almost completely eliminates all the microorganisms present in the food.
During a few seconds the liquid is boiled at ultra high temperatures and the almost complete destruction of possible microorganisms and spores is achieved.
Origins of pasteurization
The term pasteurization comes from the surname of the French scientist Louis Pasteur , which, together with the chemist and bacteriologist Claude Bernard , discovered this process for the first time in April 1864.
Thanks to Louis Pasteur, basic food products, such as milk, could begin to be transported long distances without being affected by decomposition. This improved both the quality of life of food and people, since food poisoning caused by pathogens was reduced.
TERRA Food-Tech® autoclaves for pasteurizing packaged foods
At TERRA Food-Tech®by RAYPA we produce compact autoclaves for packaged foods designed for the cooking, sterilization and pasteurization of canned foods in the same equipment using a temperature probe placed on a product sample. This allows a perfect control of the process while preserving the organoleptic properties, minimizing possible changes in the nutritional characteristics of the packaged product and complying with all the requirements and standards of the food industry.
In addition, for the purchase of an autoclave at TERRA Food-Tech® we offer a service of advice and technical support for the preparation of your preserves free during the first 3 months. For more information, do not hesitate to contact our sales team , we will be happy to help you.