[Methodologic problems in the bacteriological laboratory testing of disinfectants for surface disinfection in...

The intention of investigations was to clear central problems of disinfecting testing in carrier model. Ways of practical and standardized evaluation should be found out. Concrete investigations were made to guarantee a highly and regularly initial bacterial count, practical germ carriers and organic matter as also detecting damaged bacteria. Investigations for resistance level of test organisms were made in suspension test with formaldehyde as reference disinfectant. It was obviously that test organisms used in disinfecting testing were after 8 weeks more sensitive against disinfectants. Therefore results of disinfecting testing are often no representative because those test organisms are not qualified for representative declaration of disinfectant efficiency. Animal passage in distance of 8 weeks is a possibility for guaranteeing highly and regularly resistance of microorganisms We recommend to use soft wood from the same origin, addition of 10% horse serum and 1% carboxymethylcellulose as organic matter for a model relating to practice. Buffered peptone water and nutrient agar are guarantee for detecting damaged bacteria after disinfecting.