I'd like to propose a simple system for food for travelers.

For large groups:
Individual servings (entree, side dishes, deserts, etc.) are placed in little paper trays and sealed onto a larger tray that is then frozen. Cooking is simple - a tray is removed from the freezer, heated according to directions, then the served, with people taking one of the individual servings from each tray so they have an entree, side dishes, deserts, etc.

These can be supplemented with fresh fruits and vegetables from a hydroponics section or for smaller ships, small portable hydroponic units that mount onto the wall. Also, some food like canned soup that can be reheated.

For smaller groups or special dietary needs (like for a member of an alien race):

Individual frozen meals like today's TV dinners that can be placed in a microwave.

Alternately, a small box that's like a classier MRE that holds shelf-stable packaged foods and can be eaten cold or reheated. May include drink and soup mixes that require heated or chilled water. May require a specialized individual "cooking" station in the galley or crew's mess.

Or some combination of that. I've used TravelRation for the more basic shelf-stable boxed MRE, and Seares Standard Rations for fancier packaged meals. Each race has a range of numbers that allows them to select the correct ration pack for them, and may have a selection of both kinds for variety.

I welcome any other ideas someone else might have on food aboard ships.