Active Chlorine Component of Hypochlorous Acid Solution Volatilized in the Air^(*1) Eliminates Over 99% of Group A Streptococci

Osaka, Japan – Panasonic Corporation (https://www.panasonic.com/global/home.html) today announced that its Heating & Ventilation A/C Company (hereinafter referred to as Panasonic) verified that the active chloride component volatilized from the hypochlorous acid solution, produced by electrolysis of salt water, effectively eliminates over 99% of group A streptococci (GAS) adhered in a space of approx. 25 m³ within 60 minutes^(*2).

The hypochlorous acid solution is produced through the electrolysis of salt water and demonstrates high efficacy in sterilization and deodorization. Since adopting the hypochlorous acid solution for the hygiene maintenance system of cup-dispensing vending machines in 1987^(*3), Panasonic has been researching hypochlorous acid technology for over 30 years. The company verified in the past few years that the solution is effective in suppressing viruses, including the influenza virus (H1N1), novel coronavirus (SARS-CoV-2) Omicron variant, and enterovirus and coxsackievirus, which can cause hand-foot-and-mouth disease, as well as herpangina.

GAS is mainly transmitted via droplet infection (coughing and sneezing) and direct contact. These bacteria can cause a wide range of infections, such as strep throat and skin infections, and in severe cases, necrotizing fasciitis. Specifically, they are responsible for group A streptococcal pharyngitis, which primarily affects children with symptoms such as fever, sore throat, reddened tongue, and a red rash on the body. It can also cause sepsis and multiple organ failure, as exemplified by the streptococcal toxic shock syndrome, which has shown an increasing trend in recent years.

Based on the current verification results, the active chloride component volatilized from the hypochlorous acid solution is expected to eliminate GAS adhered to tables, railings, and other objects.

■Verification method
Two cases were verified: one by soaking the rotary sterilization filter in a hypochlorous acid solution of approx. 100 mg/L, exposing the filter to a given amount of wind (3.8 m³/min) to volatilize the active chloride component, and then exposing the specimens with GAS to the volatilized substance; and the other by not exposing the specimens to the active chloride component (natural attenuation).

■Verification results
The effect of suppressing 99% of GAS within 60 minutes was confirmed (Figure 1).

• Verifying organization: Kitasato Research Center for Environmental Science, Panasonic Corporation
• Verification device: The rotary sterilization filter was soaked in a hypochlorous acid solution of approx. 100 mg/L and was exposed to a specified amount of wind (3.8 m³/min) to volatilize the active chloride component.
• Verification method
  ・Exposure time: 0 to 6 hours (Exposure [with the verification device] / Non-exposure [no verification devices])
  ・Test space volume
  Exposure: Approx. 25 m³ without ventilation
  Non-exposure (natural attenuation): Approx. 25 m³ without ventilation
  [Placement of bacteria (exposure)]
  ・Placement of GAS
  Drop 10 μL of test bacterial liquid (2 μL x 5 spots) in petri dishes and dry them in a constant temperature and humidity chamber for about 50 minutes. Place the petri dishes with the test bacteria 1.5 m away from the verification device (1.2 m above the floor).
  [Placement of bacteria (non-exposure)]
  ・Place petri dishes with GAS inside a test chamber of approx. 25 m³.
• Exposure method
  Place specimens with GAS inside a test chamber of approx. 25 m³ and operate the verification device.
  ・Measurement of GAS
  Collect petri dishes at each predetermined time. Consider the liquid used to wash out the dishes as an undiluted test solution, and serially dilute it to 10 levels using the sterile saline solution. Use the pour plate method by mixing 0.1 mL of the undiluted test solution or diluted solution with TSA. Incubate the media at 36±2°C for 44 hours. After incubation, count the number of colonies formed to obtain the amount of bacteria adhered per dish.