MICROBIAL QUALITY CONTROL 75 previously been shown to be dcrmatologically safe and capable of preventing secondary contamination of the product. While formalin and mc'rcurial germicides are recognized as very powerful preservatives their use in cosmetic pro, ducts is not permitted in Japan. We have also found that some of the halogenated salicylanilides were photoallcrgenics, therefore, they were not used in our formulations for these particular products. iLricrobial Contamination During Manufacturing Process In order to accomplish the production of a microbially free cosmetic, J•: •: necessary to have microbially free materials and manufacturing facilities with no contamination during processing. Figure i shows an outline of the various manufacturing steps carried out before various controls for microbiological contaminat'ion were estab- lished. Thus far, microbial contamination was found during deaeration, cool ing, storage, and filling. In the deaeration stage, the contamination was caused by airborne micro- organisms after air discharge and when new air was supplied. During the cooling process, the contamination was caused by residual liquid after wash- ing. Due to imperfect closure during storage, as well as because of the in- complete cleansing of the tank, airborne microorganisms were found to be causes of contamination. Finally, during the filling operation, due to the fact that no clean room was available, contamination was caused by airborne Oil part• •-(Emulsification) -- (Deaeration) -- (Cooling) -- (Storage) -- (Filling) Water part • Places contaminated and causes of contamination Deaeration: Contamination caused by air borne microorganisms due to air supply. Cooling: Contamination caused by residual liquid after machine Storage: Filling: washing. a) Contamination caused by b) Contamination caused by a) Contamination caused by b) Contamination caused by c) Contamination caused by Figure 1. Possible areas for introduction of microbial process air borne microorganisms. insufficient tank cleansing. air borne microorganisms. filling machine. the container. d) Contamination caused by the worker. contamination during marefracturing

76 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS microorganisms, insufficient cleansing of the filling machine, contamination of the containers, and by the use of unskilled and careless workers. Preventing Microbial Contamination of Raw Materials A. Sterilization of Deionized Water Based upon the contamination noted in the raw materials, we considered various methods of sterilization for those raw materials, which had previously caused particular trouble. Table II shows these results, which were obtained using the sterilizer shown in Fig. 2. As deionized water is considered to be one of the most important raw materials used in the formulation and manufacture of cosmetic products, we adopted the uv sterilization treatment for the deionized water, which is used widely in other in-plant general purpose applications. B. Sterilization of Cellulose Gums The cellulose gums, used as raw materials, are often found to be con- taminated and are sources of contamination in the finished product. They may be readily sterilized by ethylene oxide gas, and under these conditions it is possible to get good sterilization. Moreover, sterilization by the ethylene oxide gas method results in a product having no noticeable change in quality and does not affect the end product. These results are shown in Table III. Prevention o[ Microbial Contamination During the Manu[acturing Process A. Microbially Free Condition During Manufacturing In consideration of a microbially free condition, processing equipment such as kettles, pipes, and cooler, etc., were automatically cleansed in a closed system, and a standardized operational method of cleansing was set up. All processing equipment (before each pieces' use in the manufacturing process) xvas sterilized as is indicated in Table IV. In order to prevent microorganisms from contaminating the kettle, all the air which was drawn into the kettle was filtered by a highly efficient Flow (Kg/hour) Table II Sterilization" of Deionized Water by uv _ Untreated Water Treated Water Microorganism count F]oxv Microorganism count (cells / ml) (Kg/hour) (cells/ml) 2400 0 2100 0 6400 0 6000 0 8800 0 10000 0 10000 0 Before uv 3.6 X 10 • Before uv 6 X 10 •Sterilizer employed: Steroline Sterilizer: Steroline System Co., Model C-4-S, Capacity: 10T/hour.