Ultraviolet Radiation-An Effective Bactericide for Fresh Meat

Ultraviolet radiation (UV), with principal energy at a wavelength of 253.7 nm, was effective in destroying bacteria on the surface of fresh meat. A radiation dose of 150 mW s/cm² (275 uW/cm² for 550 s) reduced bacteria on smooth surface meat (beef plate) about 2 log cycles (99% "kill"). Further increases in dose level to 500 mW s/cm² (275 uW/cm² for 1800 s) reduced the bacteria level one additional log cycle. Since UV radiation does not penetrate most opaque materials, it was less effective on rough surface cuts of meat such as round steak because bacteria were partly shielded from the radiation. Unlike gamma (ionizing) radiation, UV had no deleterious effects on color (Hunter "a", redness) or general appearance. UV treatment chambers could be easily installed in new or existing meat processing facilities at relatively low cost. Experimental results indicate that UV irradiation of meat carcasses could effectively increase the lag phase of bacteria multiplication until adequate cooling had occurred.