Are vacuum-packaged cosmetics really sterile?

Common ingredients in cosmetics, such as glycerin, amino acids, protein, vitamins, minerals, oils, etc., are the basic nutrients required for the growth of bacteria, and oxygen and water are the keys to the growth of bacteria. For example, after the double bond part of the unsaturated fatty acid in cosmetics encounters oxygen, an addition reaction (a characteristic reaction of unsaturated compounds) will occur to generate peroxide, and then continue to decompose the low-molecular-weight aldehydes and carboxylic acids with special odors.. After the finished cosmetics are filled into the bottler, the gas (oxygen) will be extracted through the machine, so that the bacteria will lose the hotbed for survival and be isolated from the outside world to prolong the activity and storage time of the cosmetic ingredients. However, the process of making cosmetics is not in a vacuum environment. Preservatives are added to prevent pollution from the beginning of the raw materials. Exhausting air is one of the means to delay deterioration.

Cosmetics contaminated by bacteria are just like expired cosmetics, which may cause acne. Skin wounds may cause suppuration and infection, which is even more harmful to sensitive skin. Generally, skin care products containing vitamin C, tea polyphenols, grape polyphenols, etc., start to turn yellow or have a pungent smell, which means that the product has begun to deteriorate (air infiltration or self-oxidation) and can no longer be used.