Causes: Biological; physico-chemical; contaminants; other.
The food changes depend on natural or accidental modifications of their original character.
Possible causes include:
- biological causes
- Causes physical and chemical
- chemical or physical contaminants
- Other agents
Biological causes: microorganisms, such as mold, bacteria, viruses; germs and their toxins; parasites such as tapeworm larvae, Ascaris eggs; enzymes, content is the same food and both within the human body.
Most of the food changes is due to biological causes. Foods that are more susceptible to changes are the most complete and richest acqua.Il milk is easily alterable because it has a water content of about 88%, and it is well known that water is the natural habitat of most wall of the microorganisms, which in it have the ability to rapidly multiply. In addition, the milk is also a complete food, and thus represents an ideal breeding ground for the microbial load. perishable foods are fresh butchered meats, fresh fish, fruits, and vegetables.
Causes physical and chemical
Physical causes and natural chemical (heat, light, water, air); high temperature can transform the structure of the substances, and between 10 ° and 60 ° the majority of microbes multiplies faster; the light can cause a discoloration; the water can to macerate the product; oxygen in the air due to oxidation, and the air, especially when dry, allows the evaporation of water from the food
Chemical or physical contaminants
- Chemical contaminants: pesticides (in agriculture), estrogen, antibiotics (in animal husbandry), industrial solvents, air pollutants (eg., lead, mercury), etc.
- Physical contaminants: extraneous physical particles, incorporated or mixed to foods, such as broken glass, or plastic, or metals from incorrect packaging or machinery etc.
Other agents: for example, prion, the infectious protein particle that causes BSE (cow disease). Prion develops mainly in the spinal cord of the cervical spine, so the law (D.M., 16 October 2003) prohibits the sale of bovine animals to which the spine has not been removed. It is recent news of the decision taken by the Brussels Committee to raise to a minimum of 24 months the minimum age (12 months ago) for which it is compulsory to remove the spine from cattle during slaughter; So come back to our tables the Florentine steak!
The conservation techniques (which we will deal with right away) serve to eliminate or render these various agents inactive, without altering or modifying as little as possible the intrinsic properties of foods.