One of the variables which interfere in the maintenance of sterility in the materials is the storage. There are many official and not-official recommendations for temperature and air humidity control in the storage area, however without any theoretical or experimental basis. Some hospitals do not have a system that makes the control of temperature and humidity possible, and, in most cases, the sterilizing chambers are next to the storage area, constantly releasing heat and water vapor. Considering that one of the functions of the wraps is to maintain the sterility of the content, even under adverse conditions, the recommendations to have an environmental control in the storage area, a priori, would have a secondary importance. For these reason the doubt about the real importance of the temperature and humidity in the contamination of the materials stored after the autoclave sterilization arise.
In a presentation at the International Conference on Prevention & Infection Control (ICPIC) held in Geneva, Switzerland. 29 June 29 through July 2, 2011, three researchers from the University of São Paulo in Brazil reported on an experiment in which boxes with surgical instruments and cylinders carriers were packed in cotton sheets, crepe paper, SMS and surgical-grade paper, sterilized, and intentionally contaminated externally with Serratia marcescens and stored in an environment with temperature around 35°C and air humidity around 75 percent. This group was compared with another group, the negative control, stored in temperature around 20 °C and air humidity around 60 percent. After a period of 30 days of storage, the carriers were removed from the boxes and incubated. No bacterial growth was detected in any of the samples.The researchers conclude that the high temperature and high air humidity do not interfere in the barrier efficiency of the packs.
Reference: Bruna CQDM, Graziano KU and Gomes Pinto FM. The influence of environmental temperatures and air humidity in the maintenance of the sterility of materials sterilized in different wraps. Oral presentation at International Conference on Prevention & Infection Control (ICPIC). 2011. BMC Proceedings 2011, 5(Suppl 6):P311doi:10.1186/1753-6561-5-S6-P311. http://www.biomedcentral.com/1753-6561/5/S6/P311