Tribunes

Food Security

J.J. Rodríguez Jerez

Grisc – Grup de Recerca en Gobernança del Risc (UAB)

Natural preservation of food

19 march 2010

Photo: Tinalraval

Several procedures have been considered "natural" for food preservation. The most common are the so called traditional ones, used in several countries since ancient times. But being natural does not exempt them of risks, we need to know and adequately control them to maintain the health of consumers.

One of the biggest challenges for the industry is meeting the demands for prepared foods, those that are semi or even minimally processed, that one should be able to cook with minimal effort in a short space of time and have a reasonable useful life. Producers need to find an optimal balance between freshness and taste on the one hand and safety and useful life on the other.

In fact, we find different diseases transmitted via foods that have been minimally processed (i.e., with an almost identical appearance and characteristics to fresh food). It is remarkable that even foods considered completely natural, such as organic vegetables, have been a source of disease.

Here we are facing a difficult balance. First, if we look at our history, we find that fresh foods are consumed traditionally in areas close to places where vegetables are grown or animals are raised. In remote areas, food has had to be preserved by artisan procedures, also called "natural" because of tradition.

These procedures have resulted in foods that do not resemble the raw products. Thus, between traditional treatments we can highlight the salty (or salting) of fish and meat, the dip in vinegar for marinades, as well as the smoking and fermenting of foods. This last treatment has been and is widely used because it is one produces mostly for meats, cheese, fermented milk, bread or some beverages such as beer, wine or cider.

Natural substances against microorganisms

All these above described processes incorporate additives to food in order to reduce their superficial and deep microbial contamination levels. Amongst them, salt is one that has a more important effect, known to humans for a long time. In fact, salting factories were among the first in the world that transformed food in order to sell it in distant areas. This natural salt does not act as a simple chemical component; instead it mixes the antibacterial activity of sodium chloride with the activity of other salts (especially nitrates and nitrites, powerful preservatives that inhibit the growth of microorganisms of the genus Clostridium, which produces diseases as serious as botulism).

Photo: Sergio Campos

As opposed to the salting in temperate countries, we find smoking in the cold and wet countries. In this case, preservation is guaranteed by the antimicrobial substances produced by the smoke. To this the drying is added, which increases the life span. In the case of vinegar acetic acid is added, a fermenting product. This acid prevents some microorganisms to grow in the product and increases its lifetime. In the case of fermentation, it is normal to accumulate lactic acid, which increases the acidity and facilitates preservation, and large amounts of harmless microorganisms are added that act by preventing other pathogens from growing.

As we see, these traditional treatments are effective and interesting for the efficiency they displayed in those times, even when refrigeration did not even exist.

Application conditions

The cause of most diseases through these foods has been related to a lack of hygiene These preservatives cannot be applied unless there are a number of preconditions. The most important ones are the use of a raw material of good quality with low pollution and a correct application of hygiene in the processing facilities. The cause of most diseases through these foods has been related to a lack of hygiene, especially due to an error in the production processes or in the cleaning and disinfection, as well as due to raw materials with poor control.

Furthermore, preservation technologies are not without risk. In the case of salt, excessive consumption means increased blood pressure, directly related to the occurrence of serious illnesses. Similarly, an inadequate smoking introduces toxic substances into the food from the burning wood. Many of these chemicals have been linked to tumours after continuous consumption.

Therefore, being natural or traditional does not imply a benefit in itself. Avoiding unnecessary risks to consumer health also requires control and specific safety measures.

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