You can reheat the food, not necessarily inside the Microwave to reassure you of any contamination. However, there is no evidence of food transmission yet. The coronavirus cannot even multiply in food as it requires an animal or human being to multiply. This is a respiratory illness that can cause by touching a contaminated surface. And this surface could be the food packaging as the virus can remain viable for up to 72 hours on plastic or stainless steel. So, something that you should worry about more is food packaging.