抄録
To observe the growth activity of bacteria and molds in cosmesics and toiletries, we attempted to create a device to measure the metabolic heat associated with growth nondestructively and continuously. However, in cosmetic products inoculated with microbes the growth rate is too slow to make an accurate measurement of the metabolic heat, even in a system without preservatives. we then found that the growth rate of microbes is elevated when they are adhered to material with a large specific surface area. Therefore, we examined the utility of various supports. As a result, the metabolic heat generated by the growth of the microbes became measurable by saturating a porous urethane foam with the products. This process elevated the growth activity about ten-fold.
The growth of microbes observed using this method exhibited different characteristics depending on the types and amounts of preservatives contained in the product, or on the type of microbes. The procedure employed here was found to be very useful in analyzing the preservative characteristics of the cosmetic products. It is suggested that this method can be used to evaluate quantitatively the preservative properties of cosmetics and toiletries.
