Is your janitorial or housekeeping staff doing enough to defeat the risks of COVID-19?

close up photo of person cleaning the table

If your cleaning staff is not using a disinfectant like HOCl to clean, you may not be doing enough to be protected.

Many schools, colleges, and universities often have in-house janitorial or housekeeping teams that handle the day-to-day cleaning of classrooms, hallways, dormitories, and other common areas. These services may empty trash, vacuum, clean up spills and messes, and even wipe down some shared surfaces, such as tables and door handles. But that doesn’t mean that they are effectively disinfecting all high-touch surfaces. 

  • Spray and wipe-down methods can miss up to 50% of surfaces, according to ISSA, the worldwide cleaning association.
  • In a 2008 infection control study, only about one-third of janitorial workers followed the needed dwell times listed on products.
  • In one case study conducted at a retail chain during the pandemic, Steritech, the leading provider of operational excellence assessments, found that in-house teams used a multipurpose or glass cleaner, instead of a disinfectant on high-touch surfaces 46% of the time. 

Schools evaluating their cleaning and disinfection practices may want to ensure that these teams are well-versed on what products should be used for disinfection and the appropriate dwell times. In addition, conducting periodic observations of these teams may be necessary to confirm that all high-touch surfaces are being cleaned and disinfected thoroughly. 

A professional disinfecting service, like Offshore Carpet Cleaning & Janitorial Services who uses HOCl for disinfecting, will have access to specialty equipment that can disperse HOCl in more effective ways than traditional spray and wipe down methods. 

Surfaces that need to be disinfected with solutions that kill the virus

Active school, college, and university environments are full of common areas, shared surfaces and equipment, and close contact among students and staff. Add to that the unique nature of schools and campuses – no two are exactly alike – and you have a long list of surfaces that can be potentially contaminated by coronavirus. 

Common surfaces that need to be disinfected include:

  • Appliances, equipment, and machinery
  • Chairs, benches, and seating
  • Counters
  • Desks and tables
  • Dispensers 
  • Doorknobs, handles, and push plates; other handles, pulls, buttons, and knobs
  • Door frames
  • Electronics such as keyboards, phones, remote controls, etc. 
  • Elevators and escalators
  • Light switches 
  • Lockers
  • Railings 
  • Shelves and racks
  • Sinks
  • Toilets and urinals
  • Trash cans
  • Vending machines

These surfaces need to be evaluated across all common areas of your school where students, faculty, and staff have frequent contact. Some areas may be at higher risk than others, especially if there is frequent turnover or high-traffic. The areas that need attention can vary widely from school to school. 

Statistics Show:

  • 77% of parents are concerned that in-person learning could lead to their child or their family members becoming sick.*
  • 75% of teachers are moderately or very concerned about exposure at the workplace.**
  • 1 in 3 college students do not feel safe returning to campus.^
  • 62% of faculty feel somewhat unsafe teaching or interacting with students in person.^^
  • Less than half of parents – 46% – feel their campus is prepared to handle a coronavirus outbreak.+

Provide your campus community with the reassurance that their health and safety is your top priority by having a clearly outlined disinfection plan in place. From precautionary disinfection before reopening, to routine disinfection services as part of your day-to-day cleaning strategies, to critical disinfection following a potential COVID-19 exposure, the experts at Rentokil can help. 

To speak with a specialist, call us today at 609-365-8045.

For additional guidance on reopening, visit the CDC’s Reopening Website.


Washington Post-Schar School Survey, conducted July 2020
** Gallup Survey, conducted June – July 2020
ValuePenguin.com by LendingTree Survey, July 2020.
^^ Purdue University Faculty Survey, July 2020.
TimelyMD Survey, July 2020


Hypochlorous Acid (HOCl)

An ideal disinfectant and sanitizer must be nontoxic to surface contact, noncorrosive, effective in various forms, and relatively inexpensive. HOCl may be the disinfectant of choice for coronaviruses in an oral-maxillofacial surgery (OMS) office.

HOCl is an endogenous substance in all mammals and is effective against a broad range of microorganisms. Neutrophils, eosinophils, mononuclear phagocytes, and B lymphocytes produce HOCl in response to injury and infection through the mitochondrial membrane–bound enzyme known as “respiratory burst nicotinamide adenine dinucleotide phosphate oxidase.”28 HOCl selectively binds with the unsaturated lipid layer and subsequently disrupts cellular integrity. Between pH levels of 3 and 6, the predominant species is HOCl that has maximal antimicrobial properties.29 , 30

HOCl is a powerful oxidizing agent.

In aqueous solution, it dissociates into H+ and OCl, denaturing and aggregating proteins.30 HOCl also destroys viruses by chlorination by forming chloramines and nitrogen-centered radicals, resulting in single- as well as double-stranded DNA breaks, rendering the nucleic acid useless and the virus harmless.31

How Is HOCl Made?

HOCl can be made on-site combining non-iodinated salt, water, and electrolysis. The system to make HOCl on-site is a 1-L container that is filled with water, to which 1 g of non-iodized salt and 1 teaspoon of vinegar are added. The system has the ability to make concentrations of 50 to 200 ppm (in which 1 ppm is equal to 1 mg/L) depending on its use, which is chosen by pressing a button on the instrument. The electrolyzed solution is completed in 8 minutes, when it is ready for use.

The parameters that contribute to HOCl’s efficacy as a disinfectant include contact time and concentration.323334 The method of application also will affect its efficacy to disinfect.

Stability of Solution

Rossi-Fedele et al35 investigated the shelf life of HOCl by being either exposed to or protected from sunlight. When the HOCl solution was exposed to sunlight, the chlorine reduction started on day 4. When it was sheltered from sunlight, the chlorine reduction started after day 14. The half-life increases with decreasing pH owing to the decreasing ratio of OClto HOCl.36 The parts per million (ppm) is the concentration of the –OCl, which is the active ingredient and is known as the available free chlorine (AFC) in the solution. HOCl solutions are less stable when exposed to UV radiation, sunlight, or contact with air or when the temperature of the solution is elevated greater than 25°C. HOCl solutions should be stored in cool, dark places, and contact with air should be minimized. The water for fabrication should be water that contains organic and inorganic ion concentrations that are as small as possible.37383940

Concentration Related to Time Needed for Virucidal Action

HOCl has been shown to inactivate a variety of viruses including coronaviruses in less than 1 minute.39 At a concentration of 200 ppm, HOCl is effective in decontaminating inert surfaces carrying noroviruses and other enteric viruses in a 1-minute contact time. When diluted 10-fold, HOCl solutions at 20 ppm were still effective in decontaminating environmental surfaces carrying viruses in a 10-minute contact time.40Go to:

Recommendations for Office Use

Importance of Aerosol Size to Disinfection and Application

Individuals working in the dental and medical field using surgical and high-speed handpieces are at risk from aerosolization. Aerosols are defined as particles less than 50 μm in diameter. Particles of this size are small enough to stay airborne for an extended period before they settle on environmental surfaces or enter the respiratory tract.41 , 42 Additionally, a true aerosol or droplet nuclei may be present in the air of the operatory for up to 30 minutes after a procedure.41

Particles are classified based on size: Coarse particles measure 2.5 to 10 μm; fine particles, 0.1 μm to less than 2.5 μm; and ultrafine particles, less than 0.1 μm. The nose typically filters air particles larger than 10 μm. If a particle is smaller than 10 μm, it can enter the respiratory system. If smaller than 2.5 μm, it can enter the alveoli. A particle smaller than 0.1 μm, or an ultrafine particle, such as the COVID-19 virus, can enter the bloodstream or target the lungs.

Sotiriou et al42 showed that the concentrations of small particles (<0.5 μm) generated during dental drilling procedures were much higher than the concentrations of larger particles (>1 μm). Ultrasonic and sonic transmission during nonsurgical procedures had the highest incidence of particle transmission, followed by air polishing, air-water syringe, and high-speed handpiece aerosolization.43 One study found that ultrasonic instrumentation can transmit 100,000 microbes/ft3 with aerosolization of up to 6 ft and, if improper air current is present, microbes can last anywhere from 35 minutes to 17 hours.44

Mouth Rinse

If HOCl is used as a mouth rinse, one must assume that a portion of the rinse will be swallowed. The systemic and gastrointestinal effects of ingesting HOCl, from the perspective of its use in mouthwash, was evaluated in an animal study.45 Seventeen mice were given free access to HOCl water as drinking water. No abnormal findings were observed in terms of visual inspections of the oral cavity, histopathologic tests, or measurements of surface enamel roughness, showing no systemic effect.

Other Clinical Applications


HOCl is used in the treatment of blepharitis by reducing the bacterial load on the surface of the periocular skin. Twenty minutes after application of a saline hygiene solution containing HOCl at 100 ppm, a greater than 99% reduction in the staphylococcal load was achieved.46


HOCl may be effective for cleaning biofilm-contaminated implant surfaces. HOCl significantly lowered the lipopolysaccharide concentration of Porphyromonas gingivalis when compared with sodium hypochlorite and chlorhexidine and was well tolerated by the oral tissues.47 HOCl significantly reduced bacteria on toothbrushes; it was effective as a mouthwash and for toothbrush disinfection.48

Wound Care

In a clinical study on intraperitoneal wound care, patients underwent lavage of the peritoneal cavity with 100-ppm HOCl and washing of the wound with 200 ppm.49 No adverse effects were observed.

HOCl has been shown to be an effective agent in reducing wound bacterial counts in open wounds.50 In irrigation solution in an ultrasonic system, HOCl lowered the bacterial counts by 4 to 6 logs. By the time of definitive closure, the bacterial counts were back up to 105 for the saline solution–irrigated control wounds but remained at 102 or lower for the HOCl-irrigated wounds. Postoperative closure failure occurred in more than 80% of patients in the saline solution group versus 25% of those in the HOCl group.

Hand Sanitizing

Hand antiseptics are alcohol based or non–alcohol based containing antibiotic compounds.51 Chlorine-based sanitizers, at a concentration of 50 to 100 ppm, are effective against bacteria and viruses.52 HOCl specifically used for hand sanitizers is effective at 100- to 200-ppm strengths.53 , 54

Surface Application

A study looked at disinfecting outpatient surgical centers using HOCl.55 After cleaning, the rooms in the HOCl cleaning and disinfection study arm had significantly lower bacterial counts than the rooms that underwent standard cleaning and disinfection.

HOCl Applied by Spray or Fogger

A fogger takes a solution and creates a small aerosol mist, ideally less than 20 μm in size, to disinfect an area. HOCl fogs are highly effective in the microbial disinfection of surfaces. The fogging process can alter the physical and chemical properties of the disinfectant. It was found that fogging reduced the AFC concentration by approximately 70% and increased the pH by approximately 1.3, making the solution slightly more basic; it is speculated that the loss of chlorine resulted from evaporation of chlorine gas.56 , 57 Because the changes in the properties of hypochlorous fogs are predictable, pre-fogging adjustment of the concentration and pH of the solution makes it possible to control the concentration levels to the desirable range to inactivate pathogens after fogging.40 When the appropriate concentrations are used, a study found 3 to 5 log10 reductions in both the infectivity and RNA titers of all tested viruses on both vertical and horizontal surfaces, suggesting that fogging is an effective approach to reduce viruses on surfaces.40 , 58

HOCl solutions appear to be virucidal based on concentrations above 50 ppm. HOCl was evaluated against a low-pathogenic avian influenza virus (AIV), H7N1.59 The HOCl solutions contained 50-, 100-, and 200-ppm chlorine at pH 6. Spraying with HOCl decreased the AIV titer to an undetectable level (<2.5 log10TCID50/mL) within 5 seconds, with the exception of the 50-ppm solution harvested after spraying at a distance of 30 cm. When HOCl solutions were sprayed directly onto sheets containing the virus for 10 seconds, the solutions of 100 and 200 ppm inactivated AIV immediately. The 50-ppm solution required at least 3 minutes of contact time. These data suggest that HOCl can be used in spray form to inactivate AIV.59 , 60 When the aerosol was not sprayed directly onto an inoculated surface, a lower amount of solution had a chance to come into contact with the AIV. It required at least 10 minutes of contact to be effective.61

The ability of a sprayer to make smaller particles may help a solution’s molecules to be suspended in the air for a longer period because of their low settling velocity rate. This may increase the solution’s chance of coming into contact with pathogens and inactivating them. Thus, the fogger used should have an aerosol size less than 20 μm.62Go to:

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