Effects of resterilization and storage time on sterility of paper/plastic pouches

Eur J Dent. 2018 Jul-Sep;12(3):417-421. doi: 10.4103/ejd.ejd_351_17.


Objectives: Paper/plastic pouches are widely used packaging materials for autoclaving medical and dental equipment. Although these pouches are recommended for single use, they are generally reused in Thailand. This study aimed to determine the ability of paper/plastic pouches to maintain sterility after multiple sterilization processes and stored in a closed environment for up to 6 months.

Materials and methods: A total of 6720 paper/plastic pouches were divided into four experimental groups: new pouches, 1 time, 3 times, and 5 times resterilized pouches. A piece of filter paper was placed inside each pouch, and the pouch was sealed, sterilized, and stored for up to 6 months. At the end of each storage period, the pouch was opened, and the filter paper was transferred to culture broth for microbial cultivation to determine sterility. Negative and positive controls were also used to validate the procedures.

Results: All filter papers in the experimental groups, as well as the negative control group, remained sterile for up to 6 months of storage in a closed environment. On the contrary, all filter papers in the positive control group showed microbial contamination.

Conclusions: In a closed storage condition, the paper/plastic pouches that passed multiple sterilization processes (up to 5 times resterilization) still maintained good barrier efficacy and remained sterile for up to 6 months.

Keywords: Microbial contamination; paper/plastic pouches; resterilization; sterility; storage time.