Meals Ready to Eat, also known as MREs are provisions that solders eat while out on the battlefield. All
factions and species in the military have in some way, shape, or form their own version of it. It is easily packaged for space travel and it can last a long time before spoiling.
Human MREs come in packets, no one really knows what is in them unless they read the ingredients. The ingredients are freeze dried and the flavor has been described as a unimportant detail.
Kig-Yar try to have fresh food available when ever they can but for out lasting a simple fridge they tend to carry mostly jerky and crackers, as well as canned food wine, rum, or whisky. Though their long voyage diet is mostly what ever they can loot from defeated enemies and what they can hunt on planets they stop by at. Aside from this their main method is to just put vats of stew in a cooker and just keep it at a low heat and sealed tight so that bacteria cannot spoil it.
Sirens tend to simply can their meals in large cans made of strong non corroding metals that are much larger to smaller beings such as humans. A sword may be advised for use as a can opener if you ever get ahold of them. Plus unless you get your hands on a can made for feeding your species your best bet is to water it down in case it has to much salt, as sirens don't need to be carful of their salt intake them selves. After the canned food has expired they have live sea animals in cryo-pods that they then eat instead and they can the left overs. In most ships their are even rooms with the sole purpose of breeding more animals to eat later.
Unggoy usually carry around little pouches of liquidized meals, which are referred to as food nipples. If need be, multiple Unggoy can share a single food nipple, proving the capacity of the pouch.
Turian MREs consist of a mix of dextro-based foods (because any other foods will give them cramps or worse) they are usually in similar packets to human MRE's but marked for Turian use.