RESUMO
The use of nuclear power through radiation for the destruction of microorganisms which cause food decay, infections and toxicosis, is specially for peacefull purposes. Toxoplasma gondii is a protozoa responsible for illness in humans and animals. One of the most common ways of transmission is through raw or poorly cooked meat. There is little information on the resistance of T. gondii to radiation. The objective of this research is to determine the Minimun Lethal Dose (MLD) of gamma radiation for these microorganisms. Suspensions of T. gondii containing approximately one million taquizoites/ml were irradiated with doses between 0.01 up to 0.15 HGy (kiloGray) and inoculated to mice. The surviving T gondii were re-irradiated with 0.01 up to 0.16 HGy. The irradiated protozoa were totally destroyed with 0.15 HGy dose (MLD). Taquizoites issued from live protozoa of 0.14 KGy, also were completely destroyed with dose of 0.15 KGy. No increase in resistance was observed regarding the non irradiated protozoa