We used to have crew meals in Air Bridge Carriers ( working for DHL, amongst others ) then, in 1992 or thereabouts, "due to austerity measures", along with the Christmas Party that year these were withdrawn never to re-appear. The long (continuing) saga of food was born and, in my opinion, will never be "sorted" by such an uncaring company as DHL continues to be.
They can do it if you really want to push it by refusing to do the next leg on charters but unless you are absolutely sure your case is watertight I wouldn't advise it.
The fact is ,though, you can survive without it as all the ex ABC,HCA & ACL crews will confirm.
Good luck with the sandwiches out of Vitoria though. Much time spent last year for 3 days hovering around the porcelain telephone after eating one that packed a punch.