Chemical Safety of Microwaves-Challenges

Microwave technology has been widely used in food processing. During this process, electromagnetic energy is converted into heat due to frictions at the molecular level, which results in rapid volumetric heating of food products. Besides thermal effect, some special effects are also observed during microwave processing, which is also known as the non-thermal effect. Microwave non-thermal effects are attributed to the direct interaction between alternating electromagnetic (EM) fields and polar molecules and ions. Non-thermal effects can reduce the activation energy of chemical and biochemical reactions, that change the structure of biochemical molecules. It may accelerate or slow down the rate of certain chemical reactions. To explore the non-thermal effects, it is essential to precisely exclude the thermal aspect from the microwave processing, and then analyze the mechanisms of non-thermal effect on the composition of food nutrition. These are related to chemical safety of microwave processing. At present, it has not been found that the non-thermal effect has potential risk on the chemical safety of food. But further studies are essential to reveal the mechanisms of microwave non-thermal effect on the nutritional composition. In addition, microwave packaging plays an important role in microwavable food products. The packaging must be designed to prevent any chemical migration from package materials to food or reaction with the food components during the heating process, which may otherwise compromise the safety and quality of the food products. Different types of packaging materials should be selected and tested to ensure that they meet the required safety standards.