Preservatives to prevent microbial growth that can respond or prevent microbial growth in the product material. In cosmetics, preservatives is to protect the product, to protect them from microbial contamination, extend product shelf life; to ensure the safety of products to prevent microbial contamination of the use of consumer products may be caused by infection. Cosmetic deterioration caused by microbial contamination, under normal circumstances, can be reflected in the appearance. Such as fungi and yeasts are often the edge in product packaging and other parts of moldy; microbial contamination of the product appears cloudy, precipitation, color change, PH value change, foam, taste, and if the body may occur emulsion demulsification, as block and so on. If the amount of preservative is not added, the possible growth of micro-organisms to adapt to the surrounding environment, resistance, leading to corrosion failure.
Cosmetics in the survival and reproduction of microorganisms is dependent on a number of environmental factors: the physical aspects of temperature, PH value of the environment, osmotic pressure, radiation, static pressure; chemistry with water, nutrients (C, N, P, S source ), oxygen, organic growth factors.
In some ointment etc. very low water content of products, astaxanthin the microbial growth under normal circumstances is not, for most bacteria, the most suitable for the growth of the PH range is close to neutral (6.5 ~ 7.5), acid and alkali is not suitable for the growth of microorganisms, such as the common acid products, the preservative effect is usually better than the neutral products in parallel. May increase or decrease the osmotic pressure can cause rupture of the membrane, the membrane can cause shrinkage and dehydration. Surface tension is also one of the reasons affecting microbial growth in some high amount of surfactant formulations, microbial growth is not easy, in this regard, cationic surface active agent performance more prominent, while the anionic and nonionic on the microbial physiological toxicity is very small. Under normal circumstances, the bacteria produce the most suitable temperature for 30 ℃ ~ 37 ℃, and mold and yeast is 20 ℃ ~ 25 ℃, so the high-temperature sterilization method can be used, but individual Bacillus bacteria adapt to the environment, the resulting protective film Even if 80 ℃ ~ 90 ℃ high temperature short time and can not to kill.
The role of microbial preservatives, only micro-organisms in sufficient concentration in direct contact with the case, can have an effect. Preservatives was first exposed with the cell membrane, adsorption, through the cell membrane to the cytoplasm, glutathione before playing in various parts of the efficacy and hinder cell proliferation or to kill. In fact, the main preservative of the cell wall and membrane of impact, and the other enzymes that affect cell metabolism or the activity of particles on the cytoplasmic part of the genetic structure of an impact.
Most preservatives are in contact with the cell membrane, and the cell wall of certain components, mainly with protein response, destruction of microbial cells to protect the structure or interfere with cell metabolism, cosmetics material affecting the normal growth of cells in order to achieve the preservation of purposes, mainly through the cation affect the osmotic pressure, the cell membrane rupture, shrinkage and water loss, which for sterilization. Source:http://www.cosprm.com