I was in the navy for 8 years, and I’ve had food from navy destroyers, aircraft carriers, submarine tenders, and shore duty galleys.
When a ship is in port, it always had plenty of fresh food on board. Right before a ship pulls out to sea, it is replenished with new food and drink.
If you going to be out to sea for a while, you will start to lose some of the things on board you take for granted. Fresh milk is usually one of the first things to go. They substitute it with powdered milk, and it does not even come close to real milk.
Don’t get me wrong, the food on the ship is actually pretty good, and you get plenty of it!