Efficacy of ultraviolet (UV‐C) light in reducing foodborne pathogens and model viruses in skim milk

The efficacy of low wavelength ultraviolet light (UV‐C) as a disinfection process for a scattering fluid such as skim milk was investigated in this study. UV‐C inactivation kinetics of two surrogate viruses (bacteriophages MS2 and T1UV) and three bacteria Escherichia coli ATCC 25922, S. Typhimurium ATCC 13311, Listeria monocytogenes ATCC 19115 in buffer and skim milk were investigated. UV‐C irradiation was applied to stirred samples, using a collimated beam operating at 253.7 nm wavelength. A series of known UV‐C doses (0–40 mJ·cm−2) were delivered to the samples except MS2 where higher doses (0–150 mJ·cm−2) were delivered. Biodosimetry, utilizing D values of viruses inactivated in buffer, was carried out to verify and calculate reduction equivalent dose. At the highest dose of 40 mJ·cm−2, the three pathogenic organisms were inactivated by more than 5 log10 (p 0.96). Models were validated and parameterized for predicting log reduction as a function of UV‐C irradiation dose (p