Other food preservation processes

In addition, there are other types of preservation processes which, although with different qualities, also aim to preserve the optimum conditions for food consumption, among which the following stand out:
• Ultra-freezing: consists of subjecting food to temperatures below -40ºC for relatively short periods of time (< 120 min). • Boiling: process prior to freezing in some cases, which involves boiling the food before freezing. • Sterilisation: this is one of the safest methods of food preservation, although subjecting food to high temperatures alters its properties. • Pasteurisation: this is similar to sterilisation, although lower temperatures are applied and therefore it is less effective. In order to be preserved correctly, it would have to be refrigerated afterwards or the microorganisms would recover their activity, although more slowly, for example, milk after being opened from the container. • Fermentation: this is a preservation process based on the generation of microorganisms that are not harmful to health, but which significantly alter the properties of the product. In most cases, this alteration is provoked in order to obtain a final product such as wine or cheese. • Desiccation: process that consists of making the food lose its moisture in a natural way, so that the microorganisms do not have liquid water. • Smoking: a preservation process that consists of exposing a food to smoke, altering its properties. • Vacuum packaging: consists of extracting the air that surrounds the food and in this way there is no incidence of air or microorganisms, although some of its properties, such as its shape, may be altered. • Addition of salt or salting: this is one of the oldest preservation methods in history and involves adding salt to food. • Preservation by chemical means: this involves the addition of chemical substances that nullify the activity of micro-organisms in the food, although in large quantities, they can alter its optimum conditions… • Sugar concentrates: this consists of adding sugars to natural foods, mainly fruit, with the intention of preventing oxidation of the fruit and thus avoiding contact with the air.