Food preservation is to prevent the growth of microorganisms (such as yeasts) or other microorganisms (although some methods work by introducing benign bacteria or fungi into foods), as well as slow the oxidation of fats that cause rancidity. Food preservation may also include processes that inhibit visual impairment, such as the enzymatic browning reaction on apples after they are cut during food preparation.
Many processes designed to preserve food imply more than one method of preserving food. Preserving the fruit by making it into jam, for example, involves boiling (to reduce the moisture content of the fruit and killing bacteria, etc.), sugar (to prevent its re-growth) and sealing inside an airtight jar recontamination). It has been shown that some traditional methods of preserving food have lower energy consumption and lower carbon footprint, compared to modern methods.
Some methods of food preservation are known to create carcinogens. In 2015, the International Agency for Research on Cancer of the World Health Organization classified processed meat, ie meat that has been salted, cured, fermenting and smoking, as "carcinogenic to humans". Maintaining or creating nutritional value, texture and taste is an important aspect of preserving food.
