COSMETIC PRESERVATION 213 may give to a product. For example, many eye area products were permitted to contain phenyl mercuric acetate because the risk of infection to the eye was greater than the risk of exposure to the compound. The key consideration is to judge whether the product will be safe for the consumer under normal use and foreseeable misuse conditions. One of the first considerations of a preservative is its acute toxicity. Ocular irritation and subchronic and chronic toxicity tests are performed via the expected consumer exposure route to determine at what level the preservative can exhibit any irritant, toxic, or carcinogenic properties. Perhaps more important than these tests are the skin responses to biocides. Basic irritant responses can be a result of corrosion, acute irritation, cu- mulative irritation, or photoirritation. Skin sensitization is another key concern when using biocides. Nearly all biocides used today will elicit sensitization. Sensitization testing is performed in much the same way as irritant patch testing, except that much lower concentrations and repetitive appli- cations are used. Another concern for biocides is mutagenicity testing to determine if the biocide has the potential for mutating somatic or germ cells. In addition to this testing, embryological (or developmental) toxicity testing is done to determine if the biocide may be a teratogen capable of causing birth defects. In all these tests, the results must be compared to the ordinary-use and foreseeable- misuse exposure levels to give us a reasonable risk assessment. The definition of rea- sonable risk must include considerations based on the benefits from using the biocide, the ability to use less risky biocides for the same use, the economic benefits from using the biocide (can the biocide help prevent costly recalls due to contamination?), even how the biocide may affect the quality of life, the environment, and public opinion of the company. More detail on the safety considerations of cosmetic ingredients may be found in books by Waggoner and Whittam (151,152). CONCLUSION This article does not detail or discuss the pros and cons of the various methods used in cosmetic microbiology. There are plenty of references available from which the serious student can get this information (56,153-156). Regardless of which methods are in use by any particular company, the fact that the cosmetic industry has been so successful in providing adequately preserved products for its consumers is commendable and rein- forces the wisdom that we are capable of self regulation. The cosmetic microbiologist must balance a variety of factors to provide for safe, unspoiled quality products (157). In addition to knowing preservatives, he or she must understand microbial physiology, pathogenic microbiology, and microbial ecology. In addition to microbiology, he or she must understand organic and physical chemistry, toxicology, engineering, manufacturing and processing, sanitation, and regulatory/ environmental law. The cosmetic microbiologist must use all this education and knowl- edge within the context of the business needs of the company and be able to balance risk/benefit to the consumer using the product. Finally and most importantly, this person must have the highest of ethical standards, considering himself or herself as part of the cadre of health care providers in the world dedicated to serving humankind via the mission of providing microbially safe and efficacious products.

214 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS ACKNOWLEDGMENTS I thank the many collegues who provided good insight: Phil Gels, Bill Apel, Scott Sutton, Tom Sox, Jan Curry, Stephen Richards, and Rich Hennessy. I thank Bonnie Bailey and Pat Hernandez for reviewing the paper for grammar and ease of reading. REFERENCES (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) J. C. Curry, Cosmetic microbiology 50 years of change--An historical perspective of microbiology and cosmetics, HAPPI, 8, 44-52 (1983). L. O. Kallings, O. Ringertz, L. Silverstone, and F. Ernerfeldt, Microbial contamination of medical preparations, Acta Pharm. Suec., 3, 219-228 (1966). L. J. Morse, H. L. Williams, F. P. Grenn, Jr., E. E. Eldridge, and J. R. Rotta, Septicemia due to Klebsiella pneumoniae originating from a hand cream dispenser, N. Engl. J. Med., 277, 472-473 (1967). L. J. Morse and L. F. Schornbeck, Hand lotions--a potential nosocomial hazard, N. Engl. J. Med., 278, 376-378 (1968). W. C. Noble and J. A. Sabin, Steroid cream contaminated with Pseudomonas aeruginosa, Lancet, 1, 347-349 (1966). L. A. Wilson, W. Kuehne, S. W. Hall, and D. G. Ahearn, Microbial contamination in ocular cosmetics, Am. J. Ophthalmol., 71, 1298-1302 (1971). D. G. Ahearn and L. A. Wilson, Microflora of the outer eye and eye area cosmetics, Dev. Ind. Microbial., 17, 23-25 (1976). L. A. Wilson and D. G. Ahearn, Pseudomonas-induced corneal ulcers associated with contaminated eye mascaras, Am. J. Ophthalmol., 84, 112-119 (1977). D. G. Ahearn, L. A. Wilson, A. J. Jilian, D. J. Reinhardt, and G. Ajello, Microbial growth in eye cosmetics: Contamination during use, Dev. Ind. Microbiol., 15, 221-216 (1974). L. A. Wilson, A. J. Jilian, and D. G. Ahearn, The survival and growth of microorganisms in mascara during use, Am. J. Ophthalmol., 79, 596-601 (1975). D. W. Anderson and M. Ayers, Microbiological profile of selected cosmetic products with and without preservatives after use, J. Soc. Cosm. Chem., 23, 863-873 (1972). D. W. Anderson, J. F. McConville, and C. B. Anger, Microbiological profile of used eye cosmetics by examination of product only, Cosmet. Perrum., 88, 25-27 (1973). D. W. Anderson, J. F. McConville, and C. B. Anger, Some comments on the microbiological profile of used automatic eye cosmetics by examination of both applicator and product, Cosmet. Perfum., 88, 29-30 (1973). N. L. Dawson and D.J. Reinhardt, Microbial flora of in-use, display eye shadow testers and bacterial challenges of unused eye shadows, Appl. Environ. Microbial., 42, 297 (1981). CTFA Microbiology Committee, CTFA survey: Preservative test methods companies use, Cosmet. Toiletr., 105, 79-82 (1990). R. J. Spielmaker, Report of a cosmetic industry survey concerning correlation of preservative chal- lenge and consumer use test results,J. Soc. Cosmet. Chem., 36, 5 (1985). D. K. Brannan, J. C. Dille, and D. J. Kaufman, Correlation of in vitro challenge testing with consumer-use testing for cosmetic products, Abstr. Amer. Soc. Microbiol., Session Q41, 290 (1986). D. K. Brannan, J. C. Dille, and D. J. Kaufman, Correlation of in vitro challenge testing with consumer use testing for cosmetic products. Appl. Environ. Microbial., 53, 1827-1832 (1987). S. M. Lindstrom, Consumer use testing: Assurance of microbiological product safety, Cosmet. Toiletr., 101, 71-73 (1986). S. M. Lindstrom and J. D. Hawthorne, Validating the microbiological integrity of cosmetic prod- ucts through consumer-use testing, J. Soc. Cosmet. Chem., 37, 481-488 (1986). L. R. Beucht, Influence of water activity on growth, metabolic activity and survival of yeasts and molds, J. Food Prot., 46, 135-141 (1983). J. Curry, Water activity and preservation, Cosmet. Toiletr., 100, 53-55 (1985).