Before revision: If there is an air gap (or at least, poor thermal contact) between the susceptor and food, the susceptor will heat to a much higher temperature (due to its smaller effective heat capacity when in poor contact with food), and at these higher temperatures, will radiate strongly in the infrared.
After revision: ,If there is an air gap (or at least, poor thermal contact) between the susceptor and food, the susceptor will heat to a much higher temperature (due to its smaller effective heat capacity when in poor contact with food), and at these higher temperatures, will radiate strongly in the infrared.