Abstract
Accurate thermometry is essential in the thermal evaluation of washer disinfectors. The wireless thermologger is a useful tool for the thermal evaluation of washer disinfectors because it is independent of the thermoregulatory system of the washer disinfector. The present study focuses on when washer disinfectors should be thermally evaluated, using a wireless thermologger, to assure optimal management of thermal disinfection procedures. Method: The actual disinfection temperature and thermal exposure time were evaluated using the wireless thermologger in one multi-chamber (HAMO T-840cs) and two single-chamber (HAMO T-21's) washer disinfectors installed in Tokyo University Hospital. Disinfection temperature and thermal exposure time were programmed at 93 °C for either 5 or 10 minutes in these three washer disinfectors. Thermal evaluation of the washer disinfectors was sequentially conducted three times using the wireless thermologger system. The wireless thermologger was placed in a wirebasket, which was then loaded into the washing rack. The actual disinfection temperature and thermal exposure time measured by the wireless thermologger were compared with the programmed disinfection temperature and thermal exposure time.
Results: In all three washer disinfectors, the actual disinfection temperature failed to satisfy the programmed value in the first thermal evaluations. Sequential thermal evaluations of washer disinfectors with a wireless thermologger revealed that actual disinfection temperature also failed to meet the programmed value when a washer disinfector was installed or the temperature control system was manipulated.
Conclusion: The results of the present study suggest that thermal disinfection procedures for washer disinfectors must be evaluated, using a wireless thermologger system periodically as well as at the time of installation and whenever the temperature control system is manipulated or a control panel is replaced.
 

Abstract
The presence of biological soils on instrument surfaces is the main cause of contamination related to inadequate disinfection or sterilisation. Glutaraldehyde is the most widely used high level disinfectant in France. It is known to stick on prion proteins and to reduce treatment efficacy. We have compared the efficiencies of detergents, pre-treatment products and disinfectants, in particular glutaraldehyde. The intent was to define the rank of each in the treatment cycle of reusable medical devices and to validate "in use" parameters. Microplates were contaminated by yeast extract, bovine albumin supplemented with sheep blood, fibrin and bovine serum, and exposed to products (6 detergents, 2 chemical inactivators of prions and 3 disinfectants) at different concentrations and for different times. The overall efficacy of treatments was compared to untreated control microplates. The products which are recognised as chemical prion inactivator are able to eliminate all types of soils. In particular, sodium hypochlorite was found to be interesting, including at concentrations lower than 2 % (v/v), recommended by W.H.O. These observations could broaden the use of chlorine by reduction of its corrosive effects on medical instruments.
 

Abstract
Event related sterility (ERS) is based on the concept that events, not time are responsible for contamination of sterilised supplies. In moving from a expiration dating policy to an ERS policy it is recommended that sterility testing of sample packs be carried out as part of the validation process. This is to ensure that packs which have been processed, wrapped, handled and stored in an appropriate manner will remain sterile over an extended period of time. A test method was developed and testing was carried out on a range of sample packs for four hospitals in the Brisbane area. In total 179 packs were tested with 4 positives giving a contamination rate of 2.2 %.