Food Storage Safety
When storing your prepared foods, you must make sure that they are completely cooled before you wrap and store it.
Why? Because bacteria grows fastest at temperatures between 40F and 135F and if you seal a warm food (with a lid or by wrapping it in foil or plastic) you are creating a great little environment for nasty critters to thrive.
So, by all means prepare foods ahead of time and save your leftovers. But, let them cool completely in the refrigerator before you seal them.