I always paid for all the consumables on a voyage. I'd often offer each crew member $20.00 for their special treats, and if there is a dedicated cook, that person must put together a meal and snack plan and shop accordingly. Nobody can have a stash of their "private" consumables, except that $20.00 worth, which they may or may not share at will. Since I won't take anyone on any special diets to sea, the cook basically makes 4 good meals a day, on the 4 hour on/8 hour off schedule, everybody stays well fed.
Finding that cook who can serve up a really great, warm, heaty, pot of beef stew, made mainly from cans, in any conditions, is a true gem. Save that person's number if you plan on needing a cook now and then. Never hire someone who says they are a chef. Most are prima donnas, some of whom won't even do the dishes!