degrees F and 140 degrees F).  Between these temperatures, you will have bacterial growth with a peak growth at around 35 degrees C  (95 degrees F).  Even if bacteria thrive in warmer temperatures, they do enjoy room temperature as well, where food left out of the refrigerator will spoil faster. It is well established that Listeria monocytogenes can grow at the refrigerated temperature of 4 degrees C (40 degrees F). Should we leave hot food out to cool down before putting them in the refrigerator? Check out the frequently asked questions on my web site and you will find this answer. You do not need to cool hot food before you put it into the fridge. Very hot food can be left out for 30 minutes before refrigerating. The key is to cool hot food quickly to prevent bacteria growth. Bacteria grow very well in the temperature range of 4C to 60F. Food should be cooled to 4C or lower as quickly as possible. For example, store food in shallow containers, stir hot foods occassionally to speed-up cooling and do not "stuff" your fridge. Allow cool air to circulate around food. I cooked chicken marsala on Saturday, and reheated it on Sunday. There were two portions left, which I cooled and then put in the freezer. Can I defrost them, and then heat in the microwave? Many thanks, Hilda. That depends if your chicken marsala was cooled quickly before freezing, it will be safe to reheat them in the microwave.