Not many of us are aware that microwave cooking, though easy, fast and much preferred, can cause germs to breed when food is reheated unevenly. Cold areas in the food which have not been heated get exposed to the onslaught of bacteria.
Heating large amounts or huge pieces of food in the microwave oven should be accompanied by mixing or stirring the food, so that it heats evenly.
It is advisable to completely avoid partially heated food. Further, never cook frozen food in the microwave directly, as some portions of the food may be left half-cooked exposing them to germs.