ABSTRACT
Aqueous cosmetic and drug products have a preservative system that is intended to prevent growth of microorganisms that may get into the process stream during manufacturing or into finished products during consumer use. The presence of microorganisms may have different impacts, depending on the type and number of microorganisms present and how the product is used. Contaminating bacteria, yeast, or molds may affect the aesthetics of the product by causing foaming or by changing color, odor, viscosity, etc. Products contaminated with harmful microorganisms present the most serious risk for consumers, especially for products used in sensitive areas (i.e., eye-area products) or for products used by sensitive individuals (babies, the elderly, or immunocompromised people). This is the reason why manufacturers invest in preservative efficacy testing to insure that products have an adequate preservative system, and testing of finished products-to insure that they are not contaminated with unacceptable levels of microorganisms. Although packaging sterile products in appropriate containers would eliminate the risks of microbial contamination, there is no need for such a procedure and/or the costs do not justify this for the majority of products. Questions that must be addressed are how many microorganisms are allowed and which ones can we accept without unacceptable risk?
