Cold Water Cage Wash Validation
What Happens When a Cage Washer Boiler Fails
What would you do if the boiler on your tunnel washer died on a Friday, with no repair timeline in sight and a backlog of soiled cages already stacking up? That's exactly what happened to one of our customers earlier this year. Their existing provider had no answer, so instead of waiting on a repair team, they called Quip Labs.
Their biosafety account manager, Ethan Lingenhöl, took the call. Ethan, named Vendor of the Year by the Metro NY Branch of AALAS, had a technician on-site the same week. Rather than a quick patch, the plan was to introduce an EPA-registered chlorine dioxide chemistry into the tunnel washer's wash and rinse tanks and run the entire cycle on house-hot water (otherwise known as cold water cage wash), no boiler required.
The facility wasn't interested in taking anyone's word for it, ours included. They wanted to see it. "Plate the caging," they said, "and show it works."
What's the Appropriate Method for Validating a Cold-Water Wash Cycle?
Now the question that immediately comes up during cold water cage wash validation, is "why not just use ATP?"
We recommend ATP testing in plenty of scenarios. It's fast, it's simple to run, and it's an excellent way to confirm a wash cycle removed organic soil, the job detergents and mechanical action are supposed to do. But organic soil removal and biocidal efficacy are two different questions, and a cold-water wash program depends on getting both right. The 180°F step it replaces wasn't just rinsing. It was also the critical control point in the cycle a facility relied on for microbial reduction. Quiptrol takes over that second job, and confirming a chemistry did its job requires a method that can detect microbial organisms, not just leftover residue.
Quip Labs has internal data that shows why the two don't substitute for each other. Fellow biosafety account manager David Ferguson, who's built a reputation internally as our ATP expert, analyzed 2,300 paired ATP and CFU sampling events, collected by Quip Labs personnel across five research institutions using Neogen AccuPoint ATP swabs and third-party-incubated contact plates.1
- The correlation between RLU (ATP) readings and CFU counts was weak (R² = 0.061), meaning an ATP result explains very little of the variation in the actual colony count on the same surface
- Narrowing the analysis to the RLU thresholds a vivarium would realistically use as a pass/fail cutoff didn't tighten that relationship
Some of that gap is built into what ATP measures. ATP is present in both living and recently inactivated cells, so a surface can carry a detectable ATP signal from dead cell residue even right after a disinfection step has done its job. Even at a strict RLU threshold of 10, 30% of the paired samples that passed still had a detectable CFU count on the plate.1 At a looser threshold of 50, that rose to 40%. ATP is a strong tool for verifying a surface was cleaned, and prepared for disinfection. It isn't built to confirm a biocidal step made that surface microbially safe.
How Environmental Monitoring Validated the Cold-Water Program
Plating gave this facility a direct, culture-based answer. A separate peer-reviewed study on reduced-temperature cage washing paired ATP testing with RODAC contact plates to validate 125°F and 140°F wash and rinse conditions, using defined pass thresholds of under 30 RLU for ATP and under 15 CFU per plate, with at least 90% of sampled cages required to pass in each category.2 Pairing ATP with plating is standard practice in this field for exactly the reason above: the two methods answer different questions.
The Data: Environmental Monitoring Results
Quip Labs' Expanded Lab Services team ran the sampling on-site, using D/E Neutralizing microbial contact plates, an agar formulation specifically designed to neutralize residual disinfectant chemistry, including chlorine dioxide, iodine, and quaternary ammonium compounds, before it can suppress microbial recovery on the plate. That detail matters here specifically. Without a neutralizing agent, any chlorine dioxide residue could artificially suppress colony growth on a standard plate, making a cage look cleaner than it actually is. D/E Neutralizing plates remove that variable, so a low count reflects what was actually on the surface, not an artifact of the chemistry itself.
| Sample | Location | Result |
|---|---|---|
| Positive control | N/A | 59 CFU |
| Negative control | N/A | 0 CFU |
| Stations A–D | Pre-sanitation | TNTC (too numerous to count) |
| Stations A–D | Post-sanitation | Under 10 CFU each |
The positive and negative controls behaved as expected, which is what confirms that the media itself is performing as designed. Pre-sanitation samples came back too numerous to count, consistent with heavily soiled caging before any wash cycle. Post-sanitation samples across all four stations came back under 10 CFU (worth noting that even a fully validated 180°F wash has never meant zero organisms, one related study found trace genetic material from several organisms still PCR-detectable on a portion of tunnel-washed cages without any resulting infections). Ethan and the account team are already working to refine the dosing further, with a goal of reaching zero colony-forming units rather than treating the current result as a finished benchmark.
How Quip Labs Supports Cold-Water Cage Wash Programs Long-Term
Ethan's quick thinking answered the emergency and kept their cage wash program running without a hiccup, but keeping that program reliable for years is a different problem, one that depends on consistent dosing and routine validation long after the crisis has passed. That's what MaestroChem and Expanded Lab Services are built to provide together: automated dispensing with QuipGard remote tank monitoring on the chemistry side, and the same kind of on-site plating this facility relied on to prove the program worked, offered as an ongoing service instead of a one-time response.
Facilities working with Quip Labs' Expanded Lab Services team can:
- Run ATP monitoring in-house for daily checks
- Submit their own contact plates for CFU analysis
- Bring in a full CFU+ service, where Quip Labs staff handle the sample collection, and shipment to the lab, with species-level identification available through MALDI-TOF or DNA sequencing when a result calls for it
It's the same validation logic that answered "plate it and show it works" in an emergency, offered as a standing part of a cage wash program instead of a one-time response to a crisis. What started as a field-wired workaround on a Friday afternoon is now a documented, validated program, one Ethan and the account team keep refining rather than treating as finished. That's the difference between solving a crisis and building something that lasts.
Frequently Asked Questions
Can a cage washer run without hot water if the boiler fails?
Yes. With the right chemistry and a documented switch to a house-hot cage wash program (also known as cold water cage wash), a facility can keep processing cages while a boiler is repaired. That chemistry has to be validated for the specific setup, not assumed to perform the same as the heated cycle it's replacing.
Why isn't ATP testing enough to validate a cold-water cage wash program?
ATP measures organic residue, not confirmed viable organisms, so it's well-suited to confirming a surface was cleaned, but not to confirming biocidal efficacy. Quip Labs' internal analysis of 2,300 paired ATP and CFU sampling events found only a weak correlation (R² = 0.061) between ATP readings and actual colony counts on the same surface.
What's the difference between ATP testing and CFU plate testing?
ATP testing gives a fast, indirect read on organic residue, useful for confirming a surface was cleaned and prepared for disinfection. CFU plate testing is a direct, culture-based method: contact plates grow out any organisms present so they can be counted, confirming whether a biocidal step actually worked.
What does validated cold-water cage wash monitoring data actually look like?
In one Quip Labs customer's environmental monitoring, pre-sanitation samples came back too numerous to count, while post-sanitation samples across all four stations came back under 10 CFU. Positive and negative controls performed as expected, confirming the media itself was performing as designed.
How does a facility keep a validated cage wash program reliable over time?
Ongoing dispensing oversight, like Quip Labs' MaestroChem program, paired with routine ATP and CFU validation testing through a service like Expanded Lab Services, is what keeps a program reliable long after the initial proof point, catching dosing drift before it becomes a compliance issue.
Running a workaround that needs to become a standing program?
Talk with our team about MaestroChem dispensing oversight, QuipGard tank monitoring, and Expanded Lab Services validation testing built for laboratory animal facilities.
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