Excellent question, @livertrex,. My best guess (and my practice) is to use the same food safety practices that I routinely use, and have used since my transplant in 2009.
My son, a restaurant GM tells me that the restaurants are under strict codes for food preparation safety. My own opinion is that I would select the same reputable restaurants as I would use during the average year, As far as microwaving - probably only if/when I don't eat the food within the recommended safe time .

Here is some information from the FDA about -Food Safety for Transplant Recipients. I have pasted here only the information that relates to your question. ....." If you plan to get a “doggy bag” or save leftovers to eat at a later time, refrigerate perishable foods as soon as possible—and always within 2 hours after purchase or delivery. If the leftover food is in air temperatures above 90 °F, refrigerate it within 1 hour."

You can also go to the following link to learn more.
https://www.fda.gov/food/people-risk-foodborne-illness/food-safety-transplant-recipients

Be safe and enjoy,