798 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS one of its striking properties such as pigment formation. From an in- dustrial-point of view pseudomonads can be considered, in a general sense, as motile, gram-negative rods giving a positive oxidase test. Psychro- philic pseudomonads are ubiquitous and can be isolated from soil, fresh and salt water, food, skin, and feces. Reports of pseudomonads in pharmaceuticals and cosmetic products, with the exception of ophthalmic preparations, have been scarce and one would believe that pseudomonal contamination of pharmaceuticals and, in particular, cosmetics are infrequent. The most frequent con- taminant of ophthalmic preparations and, as such, responsible for serious eye injuries and even loss of vision has been Pseudomonas aeruginosa (2, 3). Accordingly, nonsterile preparations are now regarded as adul- terated and misbranded within the U. S. Food, Drug, and Cosmetic Act. Further, multiple dose ophthalmic products must contain agents that will inhibit the growth of microorganisms (4). During the past decade a number of preservation failures in cosmetic products have been reported. Bryce and Smart (5), for example, found that contaminated hair products, of all varieties, invariably contained gram-negative organisms some of which were pseudomonads. This period coincides with the period of changeover from anionic to nonionic emulsifiers (6). These nonionic surfactants, derived from fatty acids, are responsible for the superiority of current cosmetic and pharmaceuti- cal preparations as stable, smooth, appealing, and effective formulations compared to those of 10 years ago. But nonionics have changed many preparations which could not support microorganisms into veritable cul- ture media for growth, and the contamination organisms found most fre- quently have been pseudomonas. Although there have been relatively few published reports dealing directly with pseudomonas contamination, the many publications con- cerning problems in preservation which have appeared within this same period, frequently mention this genus. Within the 1957-1960 period, for example, a dozen different pseudomonads were isolated from commer- cial and experimental formulations and this experience has occurred in several other laboratories. Thus, pseudomoniasis has been and is a con- tinuing problem. SUSCEPTIBLE PREPARATIONS AND THEIR CONTAMINANTS Pseudomonas growth has been found in or reported as responsible for the degradation of shampoos, facial lotions, sun preparations, baby prod- ucts, ophthalmic solutions, make-up products, cleansing creams, emol-

PSEUDOMONADS IN COSMETICS 799 lient creams, cleansing pads, cosmetic eye preparations, "wrinkle re- mover" solutions, cleansing sponges, protein solutions, pharmaceutical and cosmetic gels, hydrocarbon cleansing oils, and so forth. These in- clude simple solutions, O/W and W/O emulsions, triphase systems, gels, and hydrocarbon oils. The preparations from which pseudomonads are usually recovered are O/W emulsions at a pH of 7.5-8.5, which contain a significant amount of nonionics. This does not mean that formulations containing anionic or cationic emulsifiers are not subject to attack, but the presence of nonionics has been found to be most conducive to pseudomonas con- tamination. This menstruum is so favorable, that pseudomonas, be- cause of its resistance to biostatic agents, is the usual contaminant and one that grows in the product as a pure culture. At times staphylococci, aerogenes, yeasts, and molds have been isolated but never mixed with pseudomonas. Experience has indicated that a poorly preserved prod- uct is naturally contaminated only by a specific organism, e.g., a cream susceptible to pseudomonas is not susceptible to staphylococci or yeast, although a fulminating pseudomonas infection may pave the way for subsequent mold growth. The consequences to the product of heavy growth of pseudomonas are likely to be the development of a foul odor, formation of a deposit or turbidity, a change in flow and break-down of the emulsions by enzymatic activity, decolorization and/or the develop- ment of a brown color in the presence of hydrocarbon oils. A bacterial population such as is encountered in a O/W emulsion is continuously changing through adaptation or mutation. It is possible, therefore, for organisms to emerge which may develop resistance to a particular combination of inhibitors and the emulsion will ultimately spoil. The spoilage may occur after the peak of the microbial popula- tion has been reached and the microbial count is declining. Occasionally materials are seen containing as many as 5 million organisms/ml without obvious signs of deterioration. Few would believe that such material is fit for sale. A perusal of the publications on pseudomonas growth in cosmetic and other industrial products reveal the capabilities of this genus. They break down hydrocarbons (7) including petrolatum (8), remain viable for months in aircraft fuel (9), utilize alkanes such as hexane, and aromatics like benzene (10). They form inducible enzymes to benzoic and an- thranilic acid (11), produce lipases and oxidize fatty acids (12, 13), mal- tose, lactose, cellobiose, and melibiose (14). Then their enzymes liquify gelatin, attack casein, perform amylolysis (15), and are most active at