Ergosterol is an alcoholic organic substance, which is usually composed of carbon atoms, found in brewer's yeast, animal tissue and some algae and converted to vitamin D by the effect of purple iron rays. It is a chemical compound that forms colorless crystals which are insoluble in water but soluble in alcohol, benzene and ether. It is obtained from brown algae, bacteria, yeasts or rye spur in laboratory environment.

D2, which is in the fat-soluble vitamins group, is taken as ergosterol from plant foods. Ergosterol converts to calciferol when the skin is exposed to infrared rays (ultra violet rays). This substance is hydroxylated in liver and kidneys and converted into vitamin D2.

Ergosterol is an organic substance (sterol) that is found in the cell membranes of fungi and serves many of the functions cholesterol does in animal cells. Since many species of fungi cannot survive without ergosterol, the enzymes that make up it have become an important target in pharmaceutical studies. Ergosterol is a provitamin form of D2 vitamin.

Ergosterol powder is irritating to the eyes, skin and respiratory tract. If swallowed in large amounts, it causes calcium salt accumulation in the soft tissues and especially the kidneys and causes the blood calcium level to rise above normal.

Ergosterol is rarely found in nature. More dairy products used for strengthening. The main function of vitamin D in metabolism is to provide calcium and phosphorus absorption and to regulate the calcium and phosphorus balance of the organism.

Mold load in tomatoes and their products is one of the most important quality criteria. The mold load parameter is important because it shows whether the final product is produced under hygienic conditions. However, as the maximum limit of mold load varies from country to country, in recent years the level of ergosterol in tomatoes and products has been adopted as a new criterion.

Ergosterol analyzes are also performed in authorized laboratories within the framework of chemical tests. In these studies, the standards issued by domestic and foreign organizations are complied with.