Apple has 150k employees. Probably get <$15 revenue on average per employee/day, 230 days a year. So <$500M of revenue a year, and with the price/quality of the food, I doubt it's being run at a profit (It's not like they have a wine menu to boost their bottom line).
Most of those 150k employees are in retail, who don't eat at their cafeterias, and $15 is a stretch at that - I think the most I ever spent at a cafe Macs was about $10...
All that to say, you're probably off by about 80%....
I'm not sure to what extent this is true for all their cafeterias, but the Cupertino based cafeterias are very much in house, with quite a bit of executive attention. Steve Jobs made the revamp of Cafe Macs one of his first priorities on his return, and he personally recruited Francesco Longoni, who I think still runs the cafeterias, from Il Fornaio.