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Updated: Jul 11, 2026
Aseptic Laboratory Techniques: Volume Transfers with Serological Pipettes and Micropipettors
Published on: May 31, 2012
Maintenance of sterility in 1-mL polypropylene syringes
Serafin Gonzalez1, Darlene Miller, Steven P Murphy
1Department of Pharmacy, Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA. sgonzale@med.miami.edu
Purpose:
The sterility of syringes filled with a growth-promoting broth when stored under various temperature conditions was studied.
Methods:
Samples of tryptic soy broth (TSB) were injected into 150 1-mL polypropylene syringes and incubated at 33-37 degrees C for 14 days, after which time they were visually inspected for microbial contamination. In addition to visual inspection, the sterility of all syringes was tested by inoculating samples into 10-mL tubes of thioglycollate broth, incubating at 35 degrees C, and observing for growth for 5 days. After the 14-day incubation period, 30 syringes were removed for sterility validation and microbial growth promotion. TSB from 15 syringes was transferred into sterile culture tubes and challenged with Staphylococcus aureus, Escherichia coli, Bacillus cereus, Candida albicans, and Aspergillus niger. The remaining 120 syringes were repackaged and stored at room temperature (22 degrees C), in a refrigerator (5 degrees C), or in a freezer (-20 degrees C). The sterility of the samples was evaluated at 30 days, 45 days, three months, and six months.
Results:
No microbial growth was detected by visual inspection in any of the 15 syringes examined for turbidity during validation testing. All study syringes (n = 120) remained sterile throughout the respective evaluation periods, regardless of storage condition.
Conclusion:
Growth-promoting broth stored in 1-mL polypropylene syringes remained sterile when stored at room temperature, in a refrigerator, or in a freezer for six months.
