Microbiological quality control of a cage washing machine by means of a thin film culture system (PetrifilmTM)

Abstract

Washing machine effectiveness is dependent on treatment of cage surface with hot water containing detergent. The temperature of the washing chamber will not reflect the degree of treatment of each individual cage. Bacteriological testing of
cage surface will give a true indication of residual contamination. This study describes the use of rehydratable contact films to harvest and culture residual bacteria. The method registers numbers of colonies retrieved from the surface. It does not
type the bacteria and is as such a non-specific method. The study reveals that the machine in question was effective and that no bacteria were found following a normal cycle. A machine breakdown was demonstrated before the mechanical
cause was uncovered.