Extended Sanitation Intervals for Cage Components and Automated Watering Valves: Validation and Cost Analysis

Abstract

Although the Guide suggests changing rodent cage components every 2 wk, it states that "decreased sanitation frequency may be justified if the microenvironment in the cages, under the condition of use ..., is not compromised." The purpose of this study was to evaluate extended sanitation intervals of cage components (automated watering valve, wire bar lid, and filter top) of mouse individually ventilated caging (IVCs) at our institution. We hypothesized that there would be no significant difference in relative light units measured by ATP luminometry of these cage components at the control time point of 14 d as compared with each extended time interval: 28, 56, and 84 d. In addition, for automated watering valves, the study was extended to 168 d. We also hypothesized that time-and-motion studies performed by moving to a sanitation interval of 84 d for all components would result in substantial time and cost savings. The components of a total of 24 cages containing 4 or 5 mice each were swabbed, and an ATP luminometer was used to detect organic matter. We found no significant differences in organic matter load between 14 d and all other time points for all cage components. Our time- and cost-savings analysis found that extending the sanitation interval of cage components from every 2 wk (14 d) to every 3 mo (84 d) for every 10,000 cages would save about 3,000 technician hours annually, for a total annual labor cost savings of about $100,000. This study is the first to validate the extended sanitation interval of automated watering valves and confirms the findings of previous studies that validated the extended sanitation frequency of wire bar lids and filter tops of rodent IVCs. Overall, extending the sanitation frequency of cage components reduces workload of animal care staff without compromising the cage microenvironment.

Figure 1.

Swab collection pattern for each accessory. (A, B) Consistent 4- × 4-in. area at near right (when facing cage on individually ventilated caging rack) was swabbed on both the outside of wire bar lid and inside of filter top. Swabbing was performed in 3 directions with 10 passes each: vertically, horizontally, and diagonally as shown. The swab was rotated between fingers throughout swabbing to increase surface area contact. (C) The swab was passed 10 times around circumference of automated watering valve, with final swab being of front face portion. The swab was rotated between gloved fingers throughout swabbing.

Figure 2.

Mean ATP luminometer testing results in relative light units over time. No statistically significant differences were seen between any time point compared with baseline (14 d) across all cage component groups: wire bar lids (A), filter tops (B), and automatic watering valves (C).