Food preservation methods: types, characteristics and properties

An overview of the most important food preservation methods.

In an increasingly crowded and nutritionally demanding world, a production chain that maximizes the number of foodstuffs produced in the best possible preservation state is essential.

Unfortunately, not all countries have access to treated foods, and as a result, it is estimated that one in 10 people on Earth are sick at any given time from a foodborne infection. These problems are exacerbated in certain regions of the Global South, where sanitation measures are scarce and inefficient.

Therefore, knowledge of food preservation methods is essential, Therefore, knowledge of food preservation methods is very important.. Not only to know the protocols that are followed in Western countries, but to raise awareness of the rights to decent food, both at the individual and population level, that every human being should be able to exercise.

Food preservation methods: more important than they may seem.

In an introductory way and following a little bit the train of thought exposed previously, we are going to offer you a series of data reported by the World Health Organization (WHO) as far as Foodborne Diseases (FBD) are concerned:

• Every year 600 million people get sick from eating inadequately treated food.
• FBD can be fatal, especially in children under five years of age. They cause 420,000 deaths annually, 1/3 of them being infants.
• Diarrheal illnesses account for 95% of foodborne diseases in the Americas.

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

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

Of course, this long list of potential threats and the figures cited above help us to understand why the quest for food safety is a global public health priority.. This is achieved both by disinfecting them prior to consumption and by preserving them during the various stages of processing and storage until they reach the plate. This is where food preservation methods come into play, which are described below.

1. Pasteurization

Pasteurization is a thermal process carried out on liquid foods in order to reduce or eliminate the load of pathogenic agents that they may contain.. We are all familiar with the pasteurization process for dairy products such as milk, so we are not going to dwell on its methodology or its history. Rather, let's explore some of its less conventional uses.

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

It has been established that the general temperature that eliminates traces of peroxidase activity (POD, reflecting the presence of pathogenic microorganisms) in juices is an average of 90 seconds at 80ºC.

Surprisingly, these same studies report that the loss of vitamin C in these liquids can exceed 80% after pasteurization. This is attributed to the fact that vitamin C can be easily degraded by exposure to heat and oxidation. For this reason, vitamins must be added artificially in many cases..

Thus, this example shows that, despite its widespread use (not only in milk, but also in juices, beer, egg products and many other products), pasteurization also has certain reservations. By no means does this imply that it should not be done, since it is always better to lose some of the food's properties along the way than to die from a gastric infection.

2. Refrigeration

Although we all have a refrigerator at home as part of the family of indispensable household appliances, few know the preservation methods that take place in it. Let's get philosophical, because there really is no such thing as cold, so refrigeration is based on heat from a body and transmitting it to another place capable of absorbing that thermal energy (in most cases, in the (in most cases, water in the form of ice).

The purpose of the food refrigeration process is twofold:

• That meat foods be covered by a natural "film" that acts as a barrier to both oxygen and water vapor.
• Prevent the development of bacteria pathogenic to the human organism or agents that promote food putrefaction.

Thus, it can be summarized that refrigeration (and, to a greater extent, freezing) are preservation processes that protect food from environmental and biological stresses. It is worth mentioning that freezing is an even more aggressive process, since it transforms the residual moisture in the food tissues into ice crystals, which inhibits the growth of bacteria.This inhibits the growth of most bacterial species.

3. Drying or dehydration

Food drying is one of the oldest dehydration processes used by mankind. The combination of absolute preservation can be observed in freeze-dryingIt is a process that combines both freezing and dehydration stages.

We go further, because this method is not only limited to food: without preservatives or chemicals, freeze-drying is the most suitable process for preserving cells, enzymes, vaccines, viruses, yeasts, serums, Blood derivatives, algae, as well as fruits, vegetables, meats, fish and food in general.

Returning to the most primitive method, it is worth noting that during drying, the food tissue of the food loses its moisture content, resulting in a concentration of the nutrients in the remaining mass.. Even so, it is to be expected that the water-soluble vitamins will be partially oxidized, since after all the water molecules are leaving the food by evaporation. This is the case of vegetables, for example, which without human action, can lose 80% of their carotenes by the drying process.

4. Canning

Indisputably, is the most widespread commercial preservation method globally, as it is suitable for almost any type of food and allows preservation for very long periods of time.It can be used for almost any type of food and allows preservation for very long periods of time. Any microorganism present in the food is eliminated by this procedure, and no new one can access it due to its sterile condition with respect to the medium.

After the canning process, the food is subjected to a temperature of between 100º and 150º C for a certain period of time. After this sterilization period and as long as the package is not opened, it is virtually impossible for any microorganism to enter the food and alter its properties. and alter its properties.

5. Other methods

Although pasteurization, refrigeration, drying and canning are some of the most widespread methods of food preservation today in Western countries with an ironclad infrastructure, there are many others that we cannot leave out. Here are some more examples:

Salting: when treated with cooking salt, meat and fish are dehydrated. In addition, the proliferation of germs in these tissues is avoided. Smoking: the antimicrobial properties of wood smoke are used, as well as the destruction of germs and enzymes by heat. Acidification: based on the reduction of the pH of the food, which prevents the development of microorganisms, by adding acid substances such as vinegar.

Conclusions

Although the above subject matter may seem to be an anecdotal and "household matter", nothing could be further from the truth. The World Health Organization ranks foodborne diseases as one of the most important global health concerns. one of the most relevant global health concerns in the world.. For this reason, there are organizations such as the Foodborne Disease Burden Epidemiology Reference Group (FERG), in charge of monitoring epidemiological outbreaks and morbidities associated with foodborne pathologies.

For all these reasons, standardization and global distribution of the above-mentioned preservation methods is essential in order to prevent pathologies such as ascidian ascidian ascidian ascidian ascidian ascidianThe standardization and global distribution of the above-mentioned preservation methods is essential so that pathologies such as ascariasis (presence of helminth worms in feces) or bacterial infections (such as salmonellosis) become a thing of the past, especially in countries of the Global South, where this type of disorders have a not inconsiderable associated mortality.

Bibliographic references:

• Food Safety, World Health Organization (WHO). Retrieved September 9, from https://www.who.int/es/news-room/fact-sheets/detail/food-safety.
• Mora, O. O., Villareal, Y., España, D. F. M., & Ceron, A. F. (2013). Effect of pasteurization on sensory characteristics and vitamin C content in fruit juices. Biotechnology in the Agricultural and Agroindustrial Sector: BSAA, 11(2), 66-75.
• Navas, J. S. R. (2006). Freeze-drying of foods. Reciteia Journal: Reviews Of Food Science, Technology And Engineering, 6, 1.
• Brennan, J. G. (2006). Manual of food processing (No. 664 M294m). Zaragoza, ES: Acribia.