To summarize, lysozyme at relatively low concentrations is able to protect food from contamination by noroviruses, and its action is preferable to many substances used for this purpose, since lysozyme does not need to be removed from the treated food before consumption, is effective against viruses infecting cloven-hoofed domestic and wildlife animals, and is also effective against influenza and respiratory viruses in humans. The gene discussed is LYZ; the disease is influenza.