Plasma-activated water mist (PAWM) is obtained by the ignition of plasma within an air-vapor mixture. PAWM demonstrates significant antibacterial properties, decreasing loads of foodborne pathogens by a factor of 35.5 for Listeria monocytogenes, 166 for Salmonella Typhimurium, and 266 for Escherichia coli O157:H7 within 15 s. Bacterial biofilms have a similar species-dependant susceptibility. Biofilms of L. monocytogenes, Salmonella Typhimurium, and E. coli O157:H7 are destroyed by 44%, 77%, and 71%, respectively, after being treated for 2 min. Obtained results suggest importance of short-lived radicals, because PAWM condensate is not bactericidal. A new model of PAW generation as a cyclic process of oxidation reactive nitrogen species by reactive oxygen species, which occurs during effective bidirectional mass transfer between heavily humid air and water mist in plasma discharge, is presented.