Background & Objectives

UCLA DLAM's sanitation program spans 10 buildings, 21 species, and approximately 38,000 rodent cages. While an EMP had been in place, ATP bioluminescence data from a 2020 audit revealed that nearly half of all vivarium floors were failing — with swab results exceeding 500 RLU indicating unacceptable levels of residual organic material. In some areas, readings exceeded 10,000 RLU. Three different chemistries were in active use, all with cotton mops, none delivering consistent results.

The team identified four core objectives for this study:

1. Consolidate to one cleaner/disinfectant — select a single product that cleans effectively, leaves no residue, and is cost-efficient across all animal room surfaces.

2. Confirm no behavioral aversion — the psychology department required that no new cleaning product interfere with ongoing behavioral experiments; the labs had used the same cleaner since approximately 1985.

3. Establish a reproducible mopping protocol — develop a standardized process that could be documented, trained, and consistently followed by all technicians.

4. Validate with ATP testing — define pass/fail benchmarks (≤2,500 RLU for floors; ≤150 RLU for caging) and establish a quarterly testing schedule for all areas and supplies.

Methods

Mop & Chemistry Comparison

Four experimental groups were established by pairing two mop types (microfiber and cotton) with two chemistries (quaternary ammonium and hydrogen peroxide): Microfiber-Quat, Microfiber-H₂O₂, Cotton-Quat, and Cotton-H₂O₂. Each group received a 2-in-1 mop bucket and a defined mopping protocol. ATP swabs were collected before and after mopping in four animal rooms weekly for three weeks. A paired T-test was used to evaluate statistical significance.

Behavioral Aversion Testing

A three-chamber preference assay was used at the Behavioral Testing Core. Each side chamber was sprayed 15 times with either water or a test cleaner, then air-dried. Animals received 10 minutes of habituation in the water (center) chamber, followed by 10 minutes of free exploration across all three chambers. The box was rotated between subjects to control for room-side preference. Thirty-two mice and eighteen rats each completed two exposures. Time spent in each chamber was analyzed to determine preference or aversion.

Spray Bottle Stability (Quat Binding Validation)

Quaternary ammonium cations can become neutralized in solution, reducing germ-killing efficacy — a phenomenon known as quat binding. To address this concern, quat was placed in a spray bottle to simulate hood use. Hydrion® pH and sanitizer test strips (Quat Check 1000) were dipped daily for three weeks to verify parts per million (ppm) remained above the effective threshold of 1,000 ppm.

Results

ATP Reduction by Mop Type & Chemistry

Microfiber mops outperformed cotton mops in both chemistry groups. The most clinically meaningful improvement — microfiber with quat — delivered a 68% reduction in ATP (p=0.088). Microfiber with H₂O₂ achieved a 79% reduction (p=0.004), a statistically significant result, though H₂O₂ was ultimately eliminated for other reasons. Cotton mops with either chemistry produced only a 48% reduction in both cases.

Behavioral Aversion Testing

Mice showed a highly significant aversion to H₂O₂ (p<0.0001), spending substantially less time in the H₂O₂-treated chamber. Rats trended toward a similar aversion. Critically, neither species demonstrated any preference or aversion to quaternary ammonium — confirming that switching to quat would not disrupt behavioral research protocols. Due to the aversion findings, quat was also selected for hood use in place of H₂O₂.

Parameter Comparison Summary

Quat Spray Bottle Stability

Concerns around quat binding — whereby quaternary ammonium cations become neutralized in cleaning solution over time — were directly tested. Quat maintained a concentration above 1,000 ppm for the full three-week monitoring period when stored in spray bottles, confirming suitability for daily hood use without daily dilution.

Conclusions

Both microfiber-based protocols significantly reduced organic soil load compared to cotton mops. While H₂O₂ with microfiber achieved a marginally higher ATP reduction (79% vs. 68%), it was categorically disqualified by the behavioral data: mice showed a highly significant aversion (p<0.0001) and rats trended similarly. No such aversion was observed with quaternary ammonium.

Quat also offered practical operational advantages — no residue, no foaming, lower use concentration, and a technically simple dispensing and validation workflow. The final protocol of microfiber tube mop heads with a 2-in-1 bucket system, properly diluted quaternary ammonium from new chemical dispensing stations, and a standardized training video has now been implemented department-wide, replacing three legacy chemistries and delivering consistent, validated results across all 10 UCLA DLAM buildings.