Preservatives are used to improve the preservation of foods, preventing or slowing down their deterioration, and consequently increasing shelf-life times. Deterioration can be caused by chemical, physical and / or microbiological factors.
Not all alterations caused by microorganisms (bacteria, fungi or yeasts, molds ...) are to be considered harmful, because there are processes, triggered by some microorganisms, useful for giving a certain fragrance or flavor to the product (such as for example the stages of maturation of wine and / or cheeses).
When more preservatives are added to a food at the same time, the maximum dosage of the same decreases according to the number of preservatives used, that is: when two preservatives are used together, the maximum dosage allowed in the food is halved for each substance; if, on the other hand, three are used, the value is divided into three.
They belong to the category of preservatives:
- antimicrobials: serve to limit and hinder the development of bacterial flora, which would form in the food causing alterations of the product;
- substances which are intended for other uses, but which nevertheless have a "preservative action;
- antioxidants: these are substances that prolong the conservation period of food, preventing it from deteriorating caused by oxidative processes (such as rancidity of fats or changes in color). Antioxidants are included in the category of preservatives because they hinder the action of oxygen in contact with the product; together with the acidity regulators they are represented on the label with the word "E" followed by a number ranging from 300 to 399.
Preservatives must be reported on the label like any other additive (they are usually shown at the bottom of the labels due to their reduced percentage of concentration); those proper, are marked by the letter E followed by 3 digits between 200 and 299, or directly with the name of the preservative itself.
Within this numbering, the preservatives are further divided into 9 macro-groups shown below:
- SORBATI, from E200-209
- BENZOATES, from E210-219
- SULFURS, From E220-229
- PHENOLS AND FORMATS, from E230-239
- NITRATES
- ACETATES
- LACTATES
- PROPIONATES
- OTHERS
