2004 ANNUAL SCIENTIFIC SEMINAR 487 INTRODUCTION TO THE PRESERVATION OF MAKE-UP TYPE PRODUCTS Steven F. Schnittger Estee Lauder Companies, Inc., 125 Pinelawn Road, Melville, NY Introduction - Make-up Products Makeup products are defined as: "Cosmetics applied to the face to improve or change your appearance." It includes, eyebrow pencils, eyeliners, face powders, lip-rouge, lip gloss, lipstick, liquid or cream foundations and mascara. These products could be either aqueous based or anhydrous manufactured hot or manufactured under a cold process. This broad range of products has various levels of risk in regards to microbial contamination. Today's lecture will talk about the different types of microbiological testing, the different product types, the microbial risk factor associated with each product type, and methods of preservation. Methods of Evaluating Product Quality During the development of a product, the microbiologist may use several tools to evaluate the ability of a product to prevent the growth of microorganisms introduced during product use. The first method is the Preservative Efficacy Test, (P.E.T) which involves introducing a known quantity of microorganisms into a formula and monitoring the rate of kill over time. Not all makeup products require a P.E.T test. This is because they do not contain water, or they are manufactured at high temperatures, or because previous testing showed that the product does not support microbial growth. A second method of evaluating product quality is through an "in-use study". This is where product in its finished component, is given to a controlled population for use and after a specified amount of time, the products are returned to the micro lab for testing. The importance of a clinical in-use is that it simulates "real life" situations. This method can provide added assurance when used in combination with the PET test. The third method is the aerobic plate count (A.P.C). It is used by both the QC, and R&D microbiologist, to quantify the number of bacteria in a sample, at a specific moment in hme. A plate count should be performed on all raw materials, bulk material and finished product unless sufficient data shows that testing is not required. Other methods such as Enrichment and Stability Evaluation are required based on the type of product and area of application.

488 JOURNAL OF COSMETIC SCIENCE Risk Factors The microbiologist may perform a microbiological risk assessment of the product. Risk assessment is based on a number of factors recognized as important in evaluating the spoilage potential of a product. It is intended to guide the microbiologist and formulator in determining what level of testing is necessary to assure the quality of the product during manufacture and use. These risk factors include: Type of Emulsifier System Physical State of the Product Area of Application Frequency of Use Type of Package and Applicator Risk of Contamination during Manufacturing A good example of a high-risk product versus low-risk product is the comparison of an aqueous based mascara to an anhydrous loose powder. The mascara would be considered high risk because it is a water - based product which is being used in the eye area and could possibly be used many times a day. The loose powder would be considered low risk because it is anhydrous and does not normally support microbial growth. If the powder were recommended to be used in both a wet/dry application, than the risk factor would increase significantly. In the wet/dry application the risk would be more with the applicator than with the product alone. Once the applicator comes in contact with moisture than it has the potential to support microbial growth. Preservation of Make-up Products Today we are faced with a multitude of regulations that impact on how we formulate. The list of available preservatives that can be used in the cosmetic industry is shrinking daily. Because of this dilemma, the formulating chemist must work smarter. Preservative systems can easily be enhanced by paying close attention to a number of key factors. Raw materials such as Butylene Glycol, Hexylene Glycol, and EDTA are strongly recommended as potentiators of preservative systems. The order and temperature in which the preservative is added to the emulsion should be closely watched. Care must be taken to ensure that hydrolysis, or deactivation of the preservative does not take place due to overheating or complexing with the surfactant system. The pH of the water- phase should be kept in the acid range, to ensure the maximum efficacy of the preservative system. Conclusion The preservation and testing of makeup products is a complex subject. The type of product and its area of application play a large role in determining the type of testing required and how much preservative is needed to ensure a safe product. Hopefully, this brief presentation will the lay the ground work for giving both the new and old chemist a better insight into cosmetic microbiology.