XL750
Your airport may have a list of permitted items but crew don't just fly from one airport, each airport has its own interpretation of the national rules and the brainless numpties who take pleasure in interpreting the rules in the strictest way.
The whole thing is a mess with no common standard, if a crew member buys something to eat away from base it is a gamble if it gets past security an if you loose you will not be eating for twelve hours.