Student or Learner
Food and/or drinks purchased outside these premises is/are not allowed.
Which word in each case should I use?
Actually OR/IS is just as acceptable.
Not a teacher - AmE native
I wouldn't use "is" in that sentence.
I wouldn't use is after drinks either. It would work fine with food and drink for me.
Or and are.
If you say "food and drinks" then logically one could argue that the prohibition does not apply to just food or just a drink.