Interpretation of the requirements and usage methods for sodium hypochlorite disinfectant in the "Hygienic Requirements for Sodium Hypochlorite Generators" (GB 28233-2020)

Sodium hypochlorite generator is a device that uses salt or industrial salt solution electrolysis to produce sodium hypochlorite disinfectant. The produced sodium hypochlorite solution is a strong oxidant with strong bactericidal ability, belonging to efficient, broad-spectrum, and safe disinfectants. It is widely used for disinfecting surfaces of general environmental objects, tableware, fruits and vegetables, fabrics, drinking water, swimming pool water, sewage, and items contaminated with blood and secretions. Hygienic Requirements for Sodium Hypochlorite Generators (GB 28233-2020) Released by the State Administration for Market Regulation and the National Standardization Administration on April 9, 2020, and implemented on November 1, 2020.

1. 1. 1. Requirements for Sodium Hypochlorite Disinfectant

The fluctuation range of effective chlorine content in physical and chemical indicators is determined by the "Safety and Health Standards for Sodium Hypochlorite Generators" (GB 28233-2011) The phrase '≥ rated value' in the text has been modified to mean rated value ± 15%, and a requirement for flow rate has been added； In the killing indicators of microorganisms, due to the similar resistance of Pseudomonas aeruginosa to sodium hypochlorite disinfectant as Escherichia coli and Staphylococcus aureus, and weaker resistance than Candida albicans, the concentration of action on Pseudomonas aeruginosa has been modified to 100 mg/L, and the logarithmic suspension method for killing has been modified to ≥ 5； In terms of safety indicators, as the ammonium hypochlorite generator does not involve the production of toxic substances during the process, the drinking water and salt in its raw materials must meet the corresponding standard requirements, and the safety risks are relatively small. Therefore, the "Hygienic Requirements for Sodium Hypochlorite Generators" (GB 28233-2020) The toxicology requirements for sodium hypochlorite disinfectant have been removed from the document, and only based on the scope of use of the sodium hypochlorite generator, requirements have been made for the safety of the generated disinfectant. Regarding heavy metal indicators, when used for disinfection of drinking water, the content of lead, copper, cadmium, etc. introduced during the disinfection process should not exceed GB 5749 The limit requirements are sufficient. Therefore, the revised regulations stipulate that the hygiene quality of sodium hypochlorite disinfectant used for disinfecting drinking water should comply with the "Hygienic Safety Evaluation Specification for Disinfectants and Disinfection Equipment in Drinking Water (Trial)" According to regulations, the hygiene quality of sodium hypochlorite disinfectant used for disinfection of tableware, fruits, and vegetables should comply with the National Food Safety Standard Disinfectants (GB 14930.2-2012) The regulations.

1. 1. 2. Usage of Sodium Hypochlorite Disinfectant

The usage method does not belong to the technical content. "7.4 Usage of Sodium Hypochlorite Disinfectant" is a recommended clause. For surface disinfection of general objects, there is a certain risk of using 100 mg/L of effective chlorine for 10 minutes. Therefore, the "Hygienic Requirements for Sodium Hypochlorite Generators" (GB 28233-2020) The usage method of effective chlorine at 100 mg/L in the original standard has been deleted; Disinfection of tableware, "Safety and Hygiene Standards for Sodium Hypochlorite Generators" (GB 28233-2011) According to the "Hygienic Standards for Disinfection of Food (Beverage) Utensils" (GB 14934-1994), the disinfection of tableware is regulated in China Implemented, but the standard was revised in 2016 to "National Food Safety Standard for Disinfected Tableware (Drinking Utensils)" (GB 14934-2016) And deleted the relevant content about disinfection methods in the original standard. The disinfection method for tableware soaked in 250 mg/L of effective chlorine for 5 minutes has been widely recognized for its effectiveness over 20 years. Therefore, the "Hygienic Requirements for Sodium Hypochlorite Generators" (GB 28233-2020) The disinfection method has been retained in the document, which involves soaking in 250 mg/L of effective chlorine for 5 minutes to disinfect the utensils after residue removal and cleaning. After disinfection, the residual disinfectant should be washed away. At the same time, the label "effective against intestinal viruses" has been added, and the method of using 250 mg/L of effective chlorine for 20-30 minutes has been retained. The method of soaking in 400 mg/L of effective chlorine for 20 minutes to disinfect contaminated utensils of infectious disease patients after residue removal and cleaning, as well as soaking in 500~800 mg/L of effective chlorine for 30 minutes to disinfect utensils that have been residue removed and not cleaned, has been retained; Disinfection of fruits and vegetables, according to the Safety and Hygiene Standards for Sodium Hypochlorite Generators (GB 28233-2011) The disinfectant dosage for Chinese vegetables is (100-200) mg/L, and the action time is 10 minutes. To ensure safety, the newly revised standard has been modified to use 100 mg/L of effective chlorine for 20 minutes, and retain 200 mg/L of effective chlorine for 10 minutes. The usage method is "wash fruits and vegetables first, then disinfect them; after disinfection, rinse off the residual disinfectant with drinking water"; Disinfection of drinking water, "Safety and Hygiene Standards for Sodium Hypochlorite Generators" (GB 28233-2011)The usage method stipulates that "residual chlorine in the water at the end of the pipeline network should be ≥ 0.05 mg/L", which is not related to this standard. Therefore, it has been deleted in the newly revised standard, and only the effective chlorine content (2-4) mg/L should be retained, with a duration of 30 minutes. After disinfection, the water should comply with the "Sanitary Standards for Drinking Water" (GB 5749-2006) The requirements; Swimming pool water: Sodium hypochlorite generators are often used in the disinfection of swimming pool water. Therefore, the newly revised standard usage method has added disinfection of swimming pool water. The specific dosage depends on the volume and specific situation of the swimming pool water, but the hygiene indicators after disinfection must comply with the national standard "Hygiene Indicators and Limit Requirements for Public Places" (GB 37488-2019) For this purpose, the usage method specifies that "disinfectant should be added, and after disinfection, it should comply with GB 37488"; Disinfection of hospital sewage, sodium hypochlorite generators are often used in the disinfection of hospital sewage. Therefore, the newly revised standard usage method has added disinfection of hospital sewage and stipulated that after disinfection, it should comply with the "Discharge Standards for Water Pollutants in Medical Institutions" (GB 18466-2005)； Disinfection of excrement, due to the difficulty of producing sodium hypochlorite disinfectant with a concentration exceeding 10000 mg/L using a sodium hypochlorite generator, the revised standard has removed the "Safety and Health Standards for Sodium Hypochlorite Generators" (GB 28233-2011) The article specifies the concentration of effective chlorine content (10000~20000) mg/L for excretion disinfection.