MICROBIOLOGICAL SPOILAGE IN PHARMACEUTICALS AND COSMETICS 723 botulinum which is lethal to mice in doses of the order of 0.1 ng. Fortunately conditions for growth and toxin production are quite strict anaerobiosis, the presence of suitable pH and nutrients and of few competing bacteria is required. Such conditions are not often attained in pharmaceuticals and cosmetics and we know of no case of botulism arising from their use. Certain strains of Staphylococcus aureus produce a toxin, characterized as a specific polysaccharide, but the organism must grow to a density of several million cells per gram before its toxin becomes a problem. The evidence in connection with other bacteria, e.g. Clostridium perfringens, Bacillus cereus, Strepto- coccusfaecalis, Proteus and Pseudomonas species is less clear, but poisonous metabolites are certainly produced by a variety of fungi. Over the last decade there has been much interest shown in the aflatoxins produced by Aspergillus flayus (3). These heat-stable compounds exhibit potent toxic and carcinogenic properties in animals. A. flayus commonly infects peanuts, cotton seed and grain which are all components of animal foods. Under poor storage conditions mould growth occurs and toxic doses of aflatoxin accumulate in the food stuff. While it is difficult to visualize this occurring with cosmetics or pharmaceuticals, it is wise to ensure that ingredients such as talc, kaolin or starch are not stored for long periods under conditions supporting mould growth. Metabolic products In addition to microbial toxins, which are complex molecules and may be looked upon as biosynthetic products, simpler catabolic products such as organic acids and amines, which can be toxic to man, may be produced. Indeed, many microbial metabolites exhibit pharmacological activity (4). As these compounds are considerably less toxic than are the classic bacterial toxins, relatively high concentrations have to be attained before a spoiled product causes illness and the senses often detect that something is wrong before food spoiled to this extent is swallowed. This may not apply to medicines, as they are expected to be unpleasant and, indeed, frequently contain a flavouring agent in order to mask an unpleasant taste. However, well-documented examples incriminating specific metabolic products in pharmaceuticals are not easy to find. Irritancy Incidents of irritation following the application of cosmetics occasion- ally occur, and the offending preparation may subsequently be shown to contain a high level of microbial contamination. Direct evidence that irritation is caused by the presence of the micro-organisms is lacking but it

724 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS is reasonable to suppose that, on some occasions, the contaminants provide a source of foreign protein evoking an allergic contact dermatitis reaction or that high levels of a microbial metabolite will cause a primary irritant reaction. The eye, of course, is particularly susceptible to infection from contaminated cosmetics and it is also at risk from the direct effect of irritant metabolites left in a product even after the organisms producing them have been eradicated. Change of activity An interesting aspect, but perhaps not one of great significance, is the inactivation of biologically active molecules by organisms contaminating a. formulation. Several examples have now been demonstrated in the labor- atory and in some cases have been observed to occur in practice. A classic example is the destruction of penicillins by penicillinases, enzymes pro- duced by a broad range of micro-organisms. Microbial enzymes which in- activate chloramphenicol are also known (5) and the destruction of pre- servatives and disinfectants is established (6). Pharmacologically active substances can also be degraded. For instance Kedzia, Lewon and Wis- niewski (7) found that a loss of atropine of up to 20•o in eye drops could be caused by Corynebacterium and oeseudomonas spp. isolated from the eye drops and atropine itself. Recently, Grant, de Szors and Wilson (8) have shown that in the laboratory, a strain of Acinetobacter lwoffi, obtained from distilled water, utilized aspirin as a sole carbon source in a mineral salt solution. The same organism metabolized other active esters for instance it could degrade heroin to morphine. Another organism, Corynebacterium hoffnaii, which was isolated from laboratory dust, metabolized the anal- gesics aspirin, phenacetin and paracetamol. Loss of useful activity is not restricted to pharmaceutical products. For instance emphasis on the need for detergents which are biodegradable has had some repercussion and shampoos have been known to lose their surface-active properties due to degradation of the surfactants by con- taminating bacteria. Visible effects Visible growth When micro-organisms can actually be observed in or on a product then there is obviously no doubt that microbial spoilage has occurred. In fact, this is probably the most common way in which it is manifest. In liquid