Evaluation of disinfectants – the past begets the future

The efficacy of disinfectants is verified on the basis of the results of test methods that have undergone continuous change in line with new scientific insights. To begin with, the prime focus was on the relevance of practical measures: germ carriers were contaminated with, for example, the sputum of patients suffering from tuberculosis or with stools, while the data provided on the recoverable bacteria following exposure were very imprecise since they were based on subjective evaluation – using different methods for the various countries. With the development of the quantitative suspension test various factors of influence were analyzed for the first time and the concept of reduction factors with logarithmic units was introduced. Today, such insights are viewed as something to be taken for granted in all European and international standards. European standardization orchestrated by the European Commission received important impetus from one scientist: H. Reber. An important aspect here was that the European standards introduced and recognized in principle a separation of the methods into “in-vitro tests” and “tests conducted under everyday practice conditions”. The increasingly more precise test methods have, on the other hand, soon revealed shortcomings in the disinfectant performance of even commonly used and hitherto accepted products. This gave rise to tests with a lower margin of error and with quantitative requirements. It is only by having a uniform overview that it is possible to detect and eliminate such shortcomings. The closure of several Hygiene Institutes at German and Austrian universities and the ongoing confinement of this discipline (infection control) to microbiology have additionally meant that already today there is a shortage of infection control experts who have a holistic view of matters and are able to spearhead further development of test methods. Without experts capable of taking a holistic view of matters, it will not be possible to create an atmosphere conducive to the development, and evaluation, of test methods, as needed for quality assurance. The less often disinfectants are evaluated by competent specialists, the greater is the risk that dangers are not recognized and countered.