Methods for Inactivation of Toxoplasma gondii Cysts in Meat and Tissues of Experimentally Infected Sheep

This study utilized infectivity bioassays in cats and mice to assess the efficacy of inactivation of Toxoplasma gondii cysts in experimentally infected sheep meat and tissues subjected to chilling, freezing, heating, microwave cooking, and gamma ray irradiation. Heating at 60 degrees C or 100 degrees C for 10 minutes, freezing at either -10 degrees C for 3 days or -20 degrees C for 2 days, or irradiation at doses of 75 or 1.00 krad was sufficient to kill tissue cysts. Meanwhile, neither cooking in a microwave nor chilling at 5 degrees C for 5 days was sufficient to kill tissue cysts.