Deep-Ultraviolet Disinfection System and its Application in the Cryogenic Environment

The impact of the complex environment and cargo situation on the DUV dose had always been a challenging issue. This study designed a deep-ultraviolet (DUV) disinfection passageway-type system with specific optical design, in which the DUV light modules (wavelength ranging from 270 to 280 nm) were installed on the top, bottom, left, and right surfaces. The DUV inactivation test of staphylococcus aureus (ATCC 6538) and bacillus atrophaeus (ATCC 9372) on two widely used carriers in the food cold chain logistics were conducted in the cryogenic environment. The study found that the impact of temperature, material, or DUV dose on virucidal efficacy were different. The woven bag exhibited significantly poor virucidal efficacy compared to corrugated boxes at DUV dose levels of 37.5 mJ/cm
²
and 75.0 mJ/cm
²
. However, at higher DUV doses (e.g., 150.0 mJ/cm
²
, 225.0 mJ/cm
^2,
and 450.0 mJ/cm
²
), the woven bag demonstrated notably superior virucidal efficacy when compared to corrugated boxes. Furthermore, the work have simulated the DUV light uniformity, optimized the inner light distribution, and analyzed the influence of material reflectivity for the evaluation of the disinfection effect in the cryogenic environment.