Food preservation methods: types, characteristics and properties

In an increasingly populated world with more nutritional demands, a production chain that maximizes the number of foods generated in the best possible state of preservation is essential.

Unfortunately, not all countries have access to processed foods, which is why it is estimated that one in ten people worldwide is ill at some point due to a foodborne infection. These problems are exacerbated in parts of the South, where sanitation measures are scarce and ineffective.

For that, knowing the methods of food preservation is very important. Not only to know the protocols that are followed in Western countries, but to sensitize the population to the rights to decent food, both at the level of the individual and the population, that every human being must be able to exercise.

    Food Preservation Methods: More Important Than They Look

    As an introduction and following the thought thread presented above a bit, we will provide you with a series of data reported by the World Health Organization (WHO) regarding foodborne illness (ATE) regarding:

    • Every year, 600 million people get sick from eating untreated foods.
    • ATE can be fatal, especially in children under five. They cause 420,000 deaths per year, of which 1/3 are children.
    • Diarrheal conditions account for 95% of foodborne illnesses in the Americas.

    Bacteria of the genera Salmonella, Campylobacter and Escherichia are the most common causative agents of foodborne illness.. These infections usually present with symptoms such as fever, headache, nausea, vomiting, abdominal discomfort, and diarrhea.

    Although they are the most common bacterial agents when it comes to gastroenteritis, they are not the only ones. Viruses, parasites (the famous intestinal worms), prions and various chemicals toxic to the body (such as heavy metals, organic toxins and persistent contaminants) can also enter the body through food.

    Of course, this long list of possible threats and the numbers mentioned above allow us to understand why food safety research is a global public health priority. This is achieved both disinfectant-before consumption and preservative during the various stages of processing and storage until they reach the plate. Here come the methods of food preservation, which we present to you below.

    1. Pasteurization

    Pasteurization is a thermal process carried out on liquid foods in order to reduce or cancel out the load of pathogens they may contain. We are all familiar with the process of pasteurizing dairy products like milk, so we won’t stop at the methodology of it or its history. Better yet, let’s explore some of its less conventional uses.

    For example, it is less known that this process is also widespread in the juice and fruit juice industry. Several studies have quantified the effect of this process on the organoleptic properties of the liquid and its vitamin benefits.

    It has been established that the global temperature which eliminates traces of peroxidase activity (POD, which reflects the presence of pathogenic microorganisms) in juices is 90 seconds on average at 80 ° C.

    Surprisingly, these same studies show that the loss of the amount of vitamin C in these liquids can exceed 80% after pasteurization. This is attributed to the fact that vitamin C can be easily broken down by exposure to heat and oxidation. For that, in many cases vitamins have to be added artificially.

    Thus, this example highlights that, despite its widespread use (not only in milk, but also in juices, beer, egg products and a long list of others), pasteurization also arouses certain reservations. This does not mean that it should not be done in any way, as it will always be better to lose certain properties of the food along the way than to die from a gastric infection.

      2. Refrigeration

      While we all have a refrigerator at home as part of the must-have appliance family, not many people know the conservation methods that go into it. We become philosophical, because cold does not really exist, therefore cooling is based on extract heat from a body and transmit it to another place capable of absorbing this thermal energy (In most cases, water in the form of ice).

      The purpose of the food refrigeration process is twofold:

      • That meat-based foods be covered with a natural “film” that acts as a barrier to both oxygen and water vapor.
      • Prevent the development of bacteria that are pathogenic to the human body or agents that promote rotting of food.

      Thus, it can be summarized that refrigeration (and to a greater extent freezing) are preservation processes that protect food from environmental and biological weathering. It should be mentioned that freezing is an even more aggressive process, as it transforms residual moisture in food tissues into ice crystals., Which inhibits the growth of most bacterial species.

      3. Drying or dehydration

      Drying food is one of the oldest dehydration processes used by humans. The combination of absolute preservation is observed in lyophilizationAs it is a process that brings together the stages of freezing and dehydration.

      Let’s go further, because this method is not reduced only to food: without preservatives or chemicals, freeze-drying is the most suitable process for preserving cells, enzymes, vaccines, viruses, yeasts, sera. , blood products, algae, etc. fruits, vegetables, meats, fish and food in general.

      Coming back to the most primitive method, it should be noted that during drying, the food tissue of the food loses its moisture content, resulting in a concentration of nutrients in the remaining mass. However, water soluble vitamins are expected to be partially oxidized, as in the end the water molecules leave the food by evaporation. This is the case with vegetables, for example, which without human action, can lose 80% of their carotenes through the drying process.

      4. Canned

      undoubtedly, it is the most widely used commercial preservation method in the world, As it is used for almost all types of food and allows storage in very large temporary spaces. Any microorganisms present in the food are eliminated by this procedure, and no new ones can access them due to their condition of sterility with respect to the medium.

      After the canning process, the food is subjected to a temperature between 100 º and 150 º C for a period of time. After this sterilization period and until the container is opened, it is practically impossible for microorganisms to enter the food. and modify their properties.

      5. Other methods

      While pasteurization, refrigeration, drying and canning are among the most popular methods of preserving food today in Western countries with iron infrastructure, there are many more besides us. can’t afford in the inkwell. Here are a few more examples:

      Salty: When treated with table salt, meats and fish are dehydrated. In addition, the proliferation of germs in these tissues is prevented. Smoking: takes advantage of the antimicrobial properties of wood smoke, as well as the destruction of germs and enzymes by heat. Acidification: based on reducing the pH of the food which prevents the development of microorganisms, adding acidic substances such as vinegar.

      conclusions

      While the topic may seem anecdotal and “homemade”, nothing could be further from the truth. The World Health Organization ranks foodborne illness as a one of the most important global health problems. For this reason, there are organizations such as the Reference Group on the Epidemiology of Foodborne Morbidity (FERG), responsible for monitoring epidemiological outbreaks and morbidities associated with foodborne illnesses.

      For all this, standardization and worldwide distribution of the previously named conservation methods is essential, So that pathologies such as ascariasis (the presence of helminth worms in the stool) or bacterial infections (such as salmonellosis) belong to the past, in particular in the countries of the South, where this type of disorder has mortality associated with nothing despicable.

      Bibliographical references:

      • Food security, World Health Organization (WHO). Retrieved September 9, from https://www.who.int/es/news-room/fact-sheets/detail/food-safety
      • Mora, OO, Villarreal, I., Spain, DFM and Ceron, AF (2013). Effect of pasteurization on sensory characteristics and vitamin C content of fruit juices. Biotechnology in the agricultural and agro-industrial sector: BSAA, 11 (2), 66-75.
      • Navas, JSR (2006). Freeze-drying of food. Reciteia Journal: Reviews of Food Science, Technology, and Engineering, 6, 1.
      • Brennan, JG (2006). Food Processing Manual (No. 664 M294m). Zaragoza, EST: Acribia.

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