The wording of the memo, dated 15 Sept 1965, suggests that this wasn't the first time it had happened and not even the first time the CIA had to fire agents for food-fighting.
Muckrock has uncovered multiple CIA memos about problems with the Agency's cafeteria food (requests for cafeteria complaints are a good way to test an agency's responsiveness to FOIA). While 1965 appears to have been a real peak in shitty CIA cafeteria food, even today there are many complaints about overpriced bacon, pieces of chicken served with charred feathers still on them, and packaged sandwiches that come out of the wrapper covered in black slime.
The CIA fired "three or four" employees over a cafeteria food fight
[Jpat Brown/Muckrock]
(via Kottke)
