Related Experiment Video
Updated: Jun 18, 2026
07:45
Preparation and Maintenance of Bioexclusion IsoPositive Cage Experiment for Human Fecal Transplantation into Germ-Free Mice
Published on: February 28, 2025
Humidity and cage and bedding temperatures in unoccupied static mouse caging after steam sterilization
Gina M Ward1, Kelly Cole, Jennifer Faerber
1University Laboratory Animal Resources, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Summary
Steam sterilization of mouse cages requires over 2.5 hours of cooling to reach safe temperatures for housing. Positional effects within the autoclave impact cooling rates, especially with corncob bedding.
Area of Science:
- Laboratory animal science
- Biomedical research infrastructure
Background:
- Steam autoclaving is standard for sterilizing rodent caging and equipment.
- Ensuring appropriate environmental conditions post-sterilization is critical for animal welfare.
Purpose of the Study:
- To assess the cooling dynamics of static mouse cages after steam sterilization.
- To determine the time required for internal cage temperatures to reach safe levels for housing.
Main Methods:
- Polycarbonate mouse cages with food and corncob bedding were autoclaved.
- Hygrothermometers measured internal cage temperature, bedding temperature, and humidity every 10 minutes for 150 minutes.
- Cages from different positions (top, middle, bottom rows; edge columns) were analyzed.
Main Results:
- Initial temperatures were high (IT: 95.9°F, BT: 109.8°F, CH: 84.1%).
- Positional effects influenced cooling rates; center row cages cooled slower, top row cages had faster humidity decrease.
- After 150 minutes, average temperatures were IT: 75.8°F, BT: 77.9°F, CH: 82.4%.
Conclusions:
- A post-sterilization cooling period exceeding 2.5 hours is necessary for safe rodent housing.
- Autoclaving corncob bedding within cages prolongs the cooling time.
- Environmental conditions must be validated to ensure animal welfare post-sterilization.
Related Concept Videos
01:29Methods of Sterilization I: Physical Methods
As used in a healthcare facility, sterilization destroys all microorganisms through physical or chemical methods. The physical method includes steam, dry heat, boiling water, and radiation.
Steam sterilization uses non-toxic, low-cost moist heat in the form of saturated steam under pressure, which is fast, microbicidal, and sporicidal, and quickly warms and penetrates fabrics. Autoclaves, or steam sterilizers, expose each item to direct steam contact for a predetermined time at the necessary...
Steam sterilization uses non-toxic, low-cost moist heat in the form of saturated steam under pressure, which is fast, microbicidal, and sporicidal, and quickly warms and penetrates fabrics. Autoclaves, or steam sterilizers, expose each item to direct steam contact for a predetermined time at the necessary...
01:23Physical Methods for Controlling Microbial Growth: Temperature
Heat is a widely used method to control microbial growth by targeting and denaturing cellular proteins, thereby killing or inactivating microbes. This method's effectiveness is quantified using parameters such as the thermal death point (TDP), thermal death time (TDT), and decimal reduction time (D value). TDP represents the lowest temperature at which all microorganisms in a liquid suspension are eliminated within 10 minutes, whereas TDT is the time necessary to achieve sterilization at a...