J. Soc. Cosmet. Chem., 24, 655-662 (September 16, 1973) Some Techniques for Microbial Control ß M f 'gPla anu actann nts FREDERICK W. DAWSON, B.S.* Presented December 11, 1972, New York City Synopsis-MICROBIAL CONTAMINATION problems are a rapidly growing concern to COSMETIC MANUFACTURERS. While preservatives may limit the growth of low levels of contaminants, large numbers of microorganisms can overwhelm the preserva- tive system. The primary sources of contamination present in cosmetic preparation are MAKE-UP WATER and RAW MATERIALS. Microbial organisms from the city water supply can mttltiply rapidly in the aleionizing columns and seed the entire distribution system. Various locations within the manufacturing process then act as niduses of infection which continually shed organisms into the system. Techniques for reducing microbial levels in deionized water systems such as formalin decontamination, recirculation, point-of-use filtration, and principles of clean system de- sign are discussed. Design parameters for FILTRATION SYSTEMS capable of sterilizing other raw materials such as waxes, petrolatum, and oils, at flow rates of 8 kg/min and costs of 9 cents/kg, are presented. INTRODUCTION The problem of microbial contamination in tofietries and cosmetics is of concern to the industry, the consumer, and regulatory agencies. Pathogenic organisms such as the Pseudomonas species have been implicated as the etio- logical agents of various conditions ranging from minor skin infections to cor- nea1 ulcers and fatal septicemias. The presence of enteric organisms (Entero- bacter) should also be cause for alarm. Opportunistic pathogens such as Staphylococcus, Candida, and Corynebacterium are also undesirable in cos- metics. While these groups of organisms may not affect the normal population, they are capable of causing disease in the very young, the aged, and in persons with impaired immunological defense mechanisms. Pseudomonas organisms are not solely a health hazard. They represent a potential economic loss in terms of product spoilage. They have been respon- * Millipore Corp., Bedford, Mass. 01730. 655

656 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS sible for the degradation of shampoos, facial lotions, and sun screen prepara- tions (1). These gram-negative, nonsporulating, motile bacilli attack hydrocarbons, including petrolatum (2, 3), and utilize alkanes and aromatics such as hexane and benzene (4). They produce lipases and oxidize fatty acids (5, 6) as well as a variety of carbohydrates. In addition, they produce protolytic and amylo- lyric enzymes. They reproduce most rapidly at 25øC at a pH of 7-8. The most common source of coagulase positive Staphylococcus aureus and Corynebacterium is the plant personnel. These gram-positive organisms in- habit the nasopharynx and skin. They are responsible for a vide variety of skin infections ranging from furunculosis to an ache-like condition. Preservatives or biocidal agents are used in the final product to suppress or inactivate the flora present in the ra v materials or introduced from the en- vironment during manufacturing. In some cases, these inimical substances may be "over vhelmed" by a high level of microbial contaminants. As pointed out by Tenenbaum (1), many ingredients in current formulations can, on oc- casion, become nutrients vhich stimulate microbial growth and reduce the efficacy of preservatives. Minimizing the risk of overloading the preservative system can best be accomplished by reducing the number of bacteria going into the final product. The chief sources of contamination in cosmetic plants are the make-up ter, raw materials, and the plant environment which includes personnel. Of these, make-up vater is perhaps the source of the greatest number of gram- negative contaminants. This is particularly true vhen deionized vater is used in product preparation. CONTAMINATION S OLrRCES Make-up Water Potable vater entering the deionizing (DI) system, although free of coil- forms, contains large numbers of gram-negative bacteria. They multiply in the interstitial spaces bet veen the resin beads. This is particularly true vhen the system remains static during periods of plant inoperation. When the vater is again utilized, these bacteria are distributed throughout the piping system as vell as into the tanks used for compounding the product. They migrate through to lo v points in the system or dead ends such as unused tees, valves, etc. Here they multiply at an alarming rate. These points serve to fiu'ther seed the system vith these organisms. Species of microorganisms com- monly encountered in DI systems include Pseudomonas and Achromobacter. In many instances these organisms are able to vithstand the rigors of DI resin regeneration. Therefore, some measure must be taken to remove them from the system.