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A solution for dysfunctional dilution: real-time detection of malfunctioning automated disinfectant dispensers using colorimetric or hydrophobic wipes that indicate disinfectant concentrations

Published online by Cambridge University Press:  24 September 2025

Jennifer L. Cadnum,
Elizabeth C. EcksteinOpen the ORCID record for Elizabeth C. Eckstein[Opens in a new window],
Abhishek DeshpandeOpen the ORCID record for Abhishek Deshpande[Opens in a new window] and
Curtis J. DonskeyOpen the ORCID record for Curtis J. Donskey[Opens in a new window]
Jennifer L. Cadnum
Affiliation:
Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
Elizabeth C. Eckstein
Affiliation:
Infection Control Department, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
Abhishek Deshpande
Affiliation:
Alice L. Walton School of Medicine, Bentonville, AR, USA
Curtis J. Donskey*
Affiliation:
Geriatric Research, Education, and Clinical Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USADepartment of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, USA
*
Corresponding author: Curtis J. Donskey; Email: Curtis.Donskey@va.gov
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Abstract

Automated dispensers that dilute concentrated disinfectants with water are commonly used but can malfunction. We provide proof-of-principle that incorporating indicators into wipe products could be an effective method to provide environmental services staff with real-time visual indication that disinfectants are present and at correct concentrations with every use.

Information

Type
Concise Communication
Information
Infection Control & Hospital Epidemiology , Volume 46 , Issue 11 , November 2025, pp. 1167 - 1170
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Creative Commons
This is a work of the US Government and is not subject to copyright protection within the United States. Published by Cambridge University Press on behalf of The Society for Healthcare Epidemiology of America.
Copyright
© Department of Veterans Affairs, 2025.

Introduction

Many disinfectants used in healthcare settings are distributed as a concentrate that is diluted to in-use concentrations. These dilutable products are often dispensed from automated wall-mounted systems that mix concentrated disinfectant with water. Reference Boyce1 Monitoring of these systems has been recommended to ensure that they are working correctly. Reference Boyce1–Reference O’Neill, Ramage, Wyatt and Ballantyne3 However, in a recent survey of 10 hospitals, we found that none routinely monitored their dispenser systems and 9 had 1 or more malfunctioning dispensers. Reference Cadnum, Kaple, Eckstein, Saade, Ray, Zabarsky, Guerrero, Yassin and Donskey4 Of 107 dispensers assessed, 29 (27%) dispensed product with lower-than-expected concentrations, including 15 (14%) with no detectable disinfectant. For a peracetic acid product, 58% of systems dispensed higher-than-expected peracetic acid concentrations, potentially posing a risk to environmental services (EVS) personnel. Reference Hawley, Casey, Cummings, Edwards, Johnson and Cox-Ganser5 These findings suggest that there is an urgent need for improved strategies for monitoring of automated disinfectant dispensers.

One approach to monitor disinfectant dispensers would be to require use of test strips that measure pH or disinfectant concentrations in dispensed product. Reference Boyce1,Reference Cadnum, Kaple, Eckstein, Saade, Ray, Zabarsky, Guerrero, Yassin and Donskey4 However, this approach requires ongoing training and monitoring to ensure compliance. In our facility, we continued to occasionally detect malfunctioning dispensers despite efforts to implement monitoring for more than a year. We hypothesized that incorporating colorimetric or other indicators into dry wipes could provide real-time visual indication of the disinfectant concentration with every use. Here, we evaluated commercial colorimetric wipes that detect quaternary ammonium disinfectants and hydrophobic wipes that indicate when disinfectant is present (i.e., water with no surfactants is not absorbed). We also assessed the potential to incorporate pH or redox potential indicators into dry wipes to detect disinfectants.

Methods

Potential disinfectant indicators evaluated

Detailed information on the indicators is provided in the supplementary material. Sertun™ Rechargeable Sanitizer Indicator Towels with Color Check Technology (ITW Pro Brands, DeWitt, Iowa) change from yellow to blue when wet with solution containing quaternary ammonium disinfectant. The wipes revert to yellow when the concentration of quaternary ammonium compound is insufficient for disinfection. The wipes are marketed to the food service industry.

ContecCleanTM Cloths (Contec, Inc., Spartanburg, SC) are hydrophobic wipes that absorb liquids with surfactant but not pure water. The hydrophobic design is intended to minimize binding of quaternary ammonium disinfectants and provide uniform disinfectant application.

pH strips can be used as an indicator for disinfectants that are acidic (e.g., peracetic acid) or basic (e.g., quaternary ammonium). Reference Cadnum, Kaple, Eckstein, Saade, Ray, Zabarsky, Guerrero, Yassin and Donskey4 We did not identify commercial wipes impregnated with a pH indicator, so a proof-of-principle assessment was conducted by adding 100 µL of pH indicator solutions to sections of dry microfiber wipes. Red cabbage was boiled to obtain anthocyanin pigments that appear purple/blue in neutral, red/pink in acidic, and green/yellow in alkaline solutions. Bromophenol blue (ThermoFisher Scientific, Oakwood, Ohio) and resazurin (ThermoFisher Scientific), a redox indicator, were also evaluated.

Disinfectants tested

Virex Plus (Diversey, Fort Mill, SC) is a quaternary ammonium disinfectant with an expected in-use concentration of ∼800 parts per million (ppm) with pH 8–9. Reference Cadnum, Kaple, Eckstein, Saade, Ray, Zabarsky, Guerrero, Yassin and Donskey4 OxyCide Daily Disinfectant Cleaner (Ecolab, St. Paul, MN) is a peracetic acid/hydrogen peroxide product with an expected in-use peracetic acid concentration of ∼1300 ppm with pH ∼3. Reference Cadnum, Kaple, Eckstein, Saade, Ray, Zabarsky, Guerrero, Yassin and Donskey4,6

Laboratory evaluation of disinfectant indicator wipes

The disinfectants were diluted with tap water to provide a range of concentrations. Quaternary ammonium concentrations were measured using Micro Essential Lab Hydrion Quaternary Test Paper Kits (Fisher Scientific, Hampton, NH). pH was measured with Micro Essential Lab Single-Roll Hydrion pH Test Paper (Fisher Scientific). Peracetic acid concentrations were measured using a dropper-bottle method (Peracetic Acid Test Kit, LaMotte, Chestertown, MD).

For the Sertun and pH or redox indicator wipes, 100 µL of the disinfectant solutions or water were applied. Color change was assessed after 30 seconds. For the ContecClean wipes, 100 µL of the solutions were applied and absorption was assessed visually.

Use of the indicator wipes to assess in-use dispensers in conjunction with a hospital intervention

In our facility, an intervention that included education by Infection Control and monitoring by EVS supervisors was implemented to improve monitoring of automated dispensers of Virex Plus (see supplementary materials for details). Reference Cadnum, Kaple, Eckstein, Saade, Ray, Zabarsky, Guerrero, Yassin and Donskey4 Research personnel conducted a point-prevalence evaluation of dispensers 9 months after the intervention began. The concentration of quaternary ammonium compound was measured, and the indicator wipes were assessed for ability to detect malfunctioning dispensers.

Results

Laboratory evaluation of disinfectant indicator wipes

Figure 1 shows the color changes for the Sertun, anthocyanin, and bromophenol blue wipes and absorption with the ContecClean wipes with different concentrations of the quaternary ammonium disinfectant. The Sertun wipe remained yellow in water but developed increasing blue coloration with increasing quaternary ammonium concentrations. The anthocyanin and bromophenol blue wipes were purple in water with increasing blue coloration with increasing quaternary ammonium concentrations. The ContecClean wipe did not absorb water but did absorb solutions containing 200 ppm or more of quaternary ammonium compound.

Figure 1.

Impact of different concentrations of quaternary ammonium disinfectant on color of Sertun Rechargeable Sanitizer Indicator Towels with Color Check Technology (A), anthocyanin dye (B), and bromophenol blue (C) wipes, and on absorption with ContecClean hydrophobic wipes (D).

Wipes with anthocyanin dye, resazurin, and bromophenol demonstrated color changes that distinguished water from acidic solutions containing the peracetic acid/hydrogen peroxide disinfectant (Figure 2). With increasing peracetic acid concentrations, anthocyanin turned from blue to pink, resazurin changed from blue to orange, and bromophenol blue changed from purple to yellow.

Figure 2.

Impact of different concentrations of a peracetic acid/hydrogen peroxide disinfectant on color of wipes with anthocyanin dye (A), resazurin redox indicator (B), and bromophenol blue (C).

Use of the indicator wipes to assess in-use dispensers in conjunction with a hospital intervention

Of 46 automated dispensers assessed, 3 (6.5%) dispensed lower-than-expected quaternary ammonium concentrations, and 3 (6.5%) delivered product with no detectable disinfectant. The Sertun, anthocyanin, and bromophenol blue wipes detected all the dispensers with low or no detectable quaternary ammonium compound. The ContecClean cloths only detected dispensers with no detectable disinfectant.

Discussion

Despite efforts to implement monitoring with quaternary ammonium test strips, we have continued to find automated systems in our facility that dispense product with low or no detectable disinfectant. Our findings suggest that incorporating indicators into wipe products could provide EVS staff with real-time visual indication that disinfectants are present and at correct concentration. Although hydrophobic wipes were only able to identify situations where no disinfectant was present, colorimetric wipes that detect quaternary ammonium compounds or indicate pH or redox potential were also able to detect solutions with lower-than-expected concentrations.

Our findings provide proof-of-principle that indicator wipes could be useful, but additional work will be needed to develop optimal commercial wipe products. Indicators may be effective if applied to only a small section of a wipe rather than throughout the wipe. The addition of an easy-to-interpret indicator such as a check mark that appears only when the disinfectant concentration is adequate might be helpful. For peracetic acid/hydrogen peroxide disinfectants, there is a need for indicators of concentrations that are too high.

Our study has limitations. Wipes with pH and redox potential indicators are not commercially available. However, a pH-sensitive color indicator for detection of sanitizers on wipes or disinfectant containers has been patented. Reference Lake, Smith, Heinbuch and Molinaro7 The manufacturer of the Sertun wipe recommends repeated use for 6 to 8 hours. 8 Such repeated use would be discouraged in healthcare settings to avoid transfer of microorganisms from dirty to clean surfaces. Colorimetric indicators may be problematic for color-blind individuals. Finally, it is possible that EVS staff may ignore the color indicator on the wipes.

Although we focused on indicator wipes, alternative approaches to address malfunctioning dispensers should be considered. These might include integrating quality indicators directly into disinfectant products or incorporating quality indicator technologies into the dispenser.

Supplementary material

The supplementary material for this article can be found at https://doi.org/10.1017/ice.2025.10263.

Acknowledgments

We thank the Environmental Management Services team at the Louis Stokes Cleveland VA Medical Center for helpful discussions.

Financial support

Supported by the Department of Veterans Affairs.

Competing interests

C.J.D. has received research grants from Clorox and Ushio America. The other authors report no conflicts of interest relevant to this article.

References

Boyce, JM. Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals. Antimicrob Resist Infect Control 2016;5:10 10.1186/s13756-016-0111-xCrossRefGoogle ScholarPubMed
Boyce, JM, Sullivan, L, Booker, A, Baker, J. Quaternary ammonium disinfectant issues encountered in an environmental services department. Infect Control Hosp Epidemiol 2016;37:340–342 10.1017/ice.2015.299CrossRefGoogle Scholar
O’Neill, C, Ramage, L, Wyatt, L, Ballantyne, L. Quality control is indispensable for automated dilution systems with accelerated hydrogen peroxide. Can J Infect Control 2009;24:226–228 Google ScholarPubMed
Cadnum, JL, Kaple, CE, Eckstein, EC, Saade, EA, Ray, AJ, Zabarsky, TF, Guerrero, BJ, Yassin, MH, Donskey, CJ. Dilution dysfunction: evaluation of automated disinfectant dispenser systems in 10 hospitals demonstrates a need for improved monitoring to ensure that correct disinfectant concentrations are delivered. Infect Control Hosp Epidemiol 2024:1–4. doi: 10.1017/ice.2024.148 CrossRefGoogle Scholar
Hawley, B, Casey, M, Cummings, KJ, Edwards, N, Johnson, A, Cox-Ganser, J; National Institute of Occupational Safety and Health. Evaluation of exposure to a new cleaning and disinfection product and symptoms in hospital employees. NIOSH health hazard evaluation report, HHE 2015-0053-3269, 2017. https://stacks.cdc.gov/view/cdc/44556. Accessed May 15, 2025Google Scholar
United States Environmental Protection Agency. OxyCideTM Daily Disinfectant Cleaner. https://www3.epa.gov/pesticides/chem_search/ppls/001677-00237-20191003.pdf. Accessed May 15, 2025Google Scholar
Lake, K, Smith, C, Heinbuch, K, Molinaro, MP. Patent: pH sensitive color indicator for sanitizing applications. Application No. AU 2020274035 B2. 2020.Google Scholar
Sertun™ Rechargeable Sanitizer Indicator Towels with Color Check Technology. https://www.itwprobrands.com/product/sertun-rechargeable-sanitizer-indicator-towels. Accessed May 15, 2025Google Scholar
Figure 0

Figure 1.Impact of different concentrations of quaternary ammonium disinfectant on color of Sertun Rechargeable Sanitizer Indicator Towels with Color Check Technology (A), anthocyanin dye (B), and bromophenol blue (C) wipes, and on absorption with ContecClean hydrophobic wipes (D).

Figure 1

Figure 2.Impact of different concentrations of a peracetic acid/hydrogen peroxide disinfectant on color of wipes with anthocyanin dye (A), resazurin redox indicator (B), and bromophenol blue (C).

Supplementary material: File

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