Preservatives are substances that prevent the growth of microorganisms within a product or prevent the growth of microorganisms that react with the product. Preservatives not only inhibit the metabolism of bacteria, mold and yeast, but also affect their growth and reproduction. The preservative effect in the formulation is affected by a variety of factors, such as the temperature of the environment, the PH of the formulation, the manufacturing process, etc. Therefore, understanding the various factors helps to select and apply various preservatives.
The factors that affect the performance of cosmetic preservatives are as follows：
A. nature of preservatives
The nature of the preservative itself: the use of preservatives concentration and solubility of a great impact on the effectiveness
1, In general, the higher the concentration, the more effective;
2, Water-soluble preservatives have better preservatives performance: microorganisms usually multiply in the water phase of emulsified body, in the emulsified body, the microorganism will be adsorbed on the oil-water interface or move in the water phase.
Interaction with other ingredients in the formulation: inactivation of preservatives by some substances.
B. Production process of the product
The production environment; the temperature of the production process; the order in which the materials are added
C. Final product
The contents and outer packaging of products directly determine the living environment of microorganisms in cosmetics. Physical environmental factors include temperature, environmental pH value, osmotic pressure, radiation, static pressure; Chemical aspects include water sources, nutrients (C, N, P, S sources) , oxygen, and organic growth factors.
How is the effectiveness of preservatives evaluated?
The minimal inhibitory concentration (MIC) is the basic index to evaluate the effect of preservatives. The less the MIC value is, the higher the effect is.
The MIC of preservatives was obtained by experiments. Different concentrations of preservatives were added to the liquid medium by a series of dilution methods, and then the microorganisms were inoculated and cultured, the lowest inhibitory concentration (MIC) was selected by observing the growth of microorganisms.
Post time: Mar-10-2022