FP/maternal and child health clinics in many countries do not have sterilization
equipment (autoclaves). Although high-level disinfection (HLD) by boiling or soaking in
chemical disinfectants is an acceptable alternative, neither of these HLD methods is
practical for processing surgical gloves, which must be dried before use. To find a more
practical HLD method, experiments were conducted using a commercially available,
inexpensive three-tiered steam cooker (about $5 US) to steam the gloves.
The cooker consisted of a bottom pan for
boiling water, three steam pans stacked on top of each other and a lid to seal the
assembly (see illustration). Multiple 5 mm holes in the bottom of each pan permitted steam
to pass upwards, and water (from steam condensation) to pass back down.
Method: Output from an iron/Constantan thermocouple was
used to determine temperature changes 1) in the empty pans and 2) when each pan contained
31 latex gloves. After the water in the steam cooker was brought to a rolling boil, the
output was recorded at 20- to 60-second intervals for 20 minutes and time/temperature
profiles were plotted as an average of duplicate runs.
In addition, new gloves were contaminated with known amounts of S. aureus, S.
epidermidis, P. aeruginosa and C. albicans as well as B. subtilis (heat-sensitive) and B.
stearothermophilis (heat- resistant) endospores, steamed for 20 minutes and then cultured.
Results: The temperature reached 96 C within 1 to 2 minutes in all
three empty pans and remained at 96–98 C (±2 ) for the remainder of the test. With
31 gloves placed in each of the three pans to simulate expected use conditions, the
internal glove temperature rose to 96 C within 4 minutes in the bottom and middle pans and
in 6 minutes in the highest pan. Following each experiment, the gloves were cooled,
allowed to air dry, and visually checked for damage and durability. Visual examination
revealed no cracks, surface damage or yellowing of the gloves. In addition, no growth was
observed for all microorganisms tested as well as for B. subtilis (heat-sensitive)
endospores after 24 hours’ incubation with 6, 15 or 30 gloves per pan.
Conclusion: Based on the results of this study, steaming in an
inexpensive steamer is a practical, effective method for HLD of surgical gloves. And,
depending on the size of the cooker, this method can be used for the HLD of metal
instruments, plastic items such as manual vacuum aspiration (MVA) cannula or syringes and
rubber items (catheters) as well.
Major Advantages: Steaming uses less water than boiling for HLD,
thereby saving energy, and is less damaging for latex gloves and plastic items. Also,
where the quality of the water is poor (contaminated, alkaline pH or contains particulate)
steaming is preferable to boiling.
More
