Perishable food products can be preserved for a long time by applying a preservation method to them. Boiling fruits and berries with honey or sugars, urinating, pickling, pickling, and other methods have been used by people for a long time. Food preservation has become ecologically important with difficult economic times, including the COVID-19 pandemic (Sridhar et al. 1715). Various methods of influencing microorganisms have been widely studied and have found practical use, making it possible to preserve food products without spoilage for a long time. There are several classifications of food preservation based on microbiological and spoilage mechanisms, on which it is possible to describe the main methods of preserving products.
The first group includes storage methods based on the basic principle: they aim at maintaining life processes at a reduced level but with the preservation of natural immunity. This principle is based on the storage of fresh fruits and vegetables and live fish storage (Sridhar et al. 1718). In the second group are storage methods based on the principle of abiosis, which aims to destroy microbes in the product. These include pasteurization, sterilization, the use of antiseptics, antibiotics, and sonication.
Storage methods based on the principle of anabiosis aim to suspend the vital activity of microbes in products. At the same time, such conditions are created under which microorganisms can remain alive but not viable. These include: creating low temperatures, removing water from the product – drying, creating a high osmotic pressure with salt sugar, increasing acidity, and creating anaerobic conditions (Sridhar et al. 1719). Finally, storage methods based on the principle of cenoanabiosis are aimed at using antagonistic relationships between microorganisms that make up the microflora of the product. At the same time, conditions are created for the development of microorganisms, which change the properties of the product in the course of their life activity to improve its nutritional and taste qualities. The waste products of these microorganisms inhibit the development of spoilage pathogens (Sridhar et al. 1726). The pickling of fruits and vegetables in fermented milk products is based on this principle.
However, more innovative approaches are available today since the ones listed above have been known to history for a long time. Ultrasonic technology and ozone treatment are applied to products sensitive to heat. Even nanotechnology for food preservation is also being considered (Sridhar et al. 1726). Nanoparticles are used as antimicrobial agents or in the fight against foodborne pathogens. Ultrasound, in turn, increases the efficiency of proteins, reduces aging time, and is used for sterilization and pasteurization (Sridhar et al., 1723). Moreover, an impulsive electric field is one of the newest methods of processing products. Typically, it is applied in drying, using less time to process products (Sridhar et al. 1727). Unlike thermal drying, this method is less energy-intensive but requires more control.
In addition to classifying methods according to microbiological mechanisms of action on products for their preservation, several other classifications are also distinguished in the food industry. First, each product is evaluated by its spoilage mechanism; secondly, conservation is limited to technologies related to the processing of products and their packaging. Spoilage is a natural process for foods and can be measured by the rate of spoilage and its mechanism. There are perishables, semi-perishables, and non-perishables. The first group, as a rule, includes products of animal origin – meat, eggs, dairy products, and the last – nuts, beans, oils, and flour.
The spoilage mechanism includes physical effects, microbiological and chemical, which trigger the corresponding processes in the product, reducing its edibility. These mechanisms often work simultaneously, not excluding each other. Moisture content, crystallization, and temperature are the main mechanisms influencing the product (Amit et al. 10). Microbiological processes include the appearance of microorganisms and the environment in which they are convenient to multiply: such processes are usually referred to as fermentation. Chemicals include proteolysis, putrefaction, oxidation, and rancidity (Amit et al. 11). Each of the spoilage mechanisms can be stopped or suspended by various conservation methods.
As a rule, the fight is against physical mechanisms, so this group has the most significant number of possible preservation methods. Pasteurization, drying, and many others – most of them have already been listed above. Biological intervention highlights only the process of fermentation; strictly speaking, fermentation is fermentation. In other words, the decomposition processes of organic substances with a lack of oxygen, which usually occur in living organisms, are natural, and the problem in preserving the product is only the need to ensure the correct course of this process (Amit et al. 12). Chemical methods involve control of the pH group and conservation. For example, canning with ethyl alcohol is used to produce semi-finished fruit juices. At an ethyl alcohol concentration of 12-16%, development is delayed, and at 18%, the vital activity of the microflora is suppressed. However, the most common application of chemical preservation methods is the packaging approach (Geueke and Muncke 491). Each material requires special processing due to the uniqueness of its properties in order to meet the requirements of sanitary safety a result.
Therefore, the preservation of products is becoming increasingly important in the world. The studied classifications suggest a division according to microbiological processes and spoilage mechanisms. Both classifications offer solutions that have been used for many centuries and are innovative and relevant today. Attention is paid not only to the processing of products but also to packaging. In the future, it may be possible to extend the shelf life of perishable goods and look for more environmentally friendly and less resource-intensive processing options such as nanotechnology and ultrasound.