Development of Cryogenic Disinfectants Using in -18 °C and -40 °C Environments - Worldwide, 2021.

Introduction: Since the outbreak of coronavirus disease 2019 (COVID-19) in Beijing Xinfadi Wholesale Market, a series of COVID-19 outbreaks has indicated the threat of transmission due to outer surfaces of objects under low temperatures. Therefore, 2 kinds of chlorine-containing disinfectants for -18 degrees C and -40 degrees C were developed in order to solve the problem of low temperature disinfection. Methods: The properties of two cryogenic disinfectants were evaluated by low-temperature test. Staphylococcus aureus and Escherichia coli were used as two indicator microorganisms to evaluate the effects of the two cryogenic disinfectants in the laboratory and field tests according to Technical Specifications for Disinfection (2002 version) and Test method for bactericidal effect of disinfectants in laboratory (GB/T 38502-2020). Results: Two disinfectants could remain in the liquid state at -18 degrees C or -40 degrees C in 72 hours without crystallization and precipitation, and the average log values of microbial reduction before and after disinfection (the average killing log value) both on Staphylococcus aureus and Escherichia coli were >3 in the laboratory and field tests. Discussion: The results showed that these two disinfectants remained functional at low temperature to disinfect the packaging of imported cold chain food and surrounding packaging to prevent transmission of COVID-19 from material to people.