COSMETIC PRESERVATION

The proper use of preservatives to prevent microbial contamination of cosmetics is often viewed as an art rather than a science. This view i s a result of the multifactorial thinking that has to go into preserva tive selection. In this general article, an historical and critical re view of preservative efficacy tests (PETs) is provided to understand t he assumptions inherent in designing PETs. A conceptual framework of m icroorganisms existing as communities in association with each other i s also promoted, which provides a different understanding of how micro organisms contaminate cosmetics and why PETs are often misinterpreted. In addition, the mode of action of preservatives is discussed and con trasted with the mode of action of antibiotics. Finally, the role of t he microbiologist is better defined in light oi the fact that he or sh e must have expertise in Far more than microbiology alone.