My local Zoo Linton Zoo is very small and has a rather small but very addequate Cafe and Gift Shop. The Cafe is in the small building but there are plenty of tables outside by the parrots within the Gardens.
The Zoo offers food such as Sausage Rolls,Jacket Potatoes,Cornish Pastry's etc and the usual Drinks aswell as a large array of chocolate and biscuits etc. It is pretty cheaply priced and freshly made so overall a pretty good deal. It may not have the big meals of other zoo's but being a small zoo it doesn't really need too. It generally doesnt get too queued up and caters for the Zoo at the right level it needs.
There are also some splendid picnic sites right within the Gardens and many people take the decision to bring their own food and eat within the Zoo Gardens during the Summer Months.
So overall = Basic Meals,Freshly made and rather cheap. Its all good.
But I do have to say one of the best meals me and my family have ever had in a Zoo would definately have to be at the new Dartmoor Zoo. It had a great range of food from what I can remember Fish and Chips, Salad, Pastries etc. It was very very nice and at a reasonable price and all made on site. I didnt have to que very much at all as it is a huge restuarant for such a small zoo. I was very suprised, the Restuarant was so profesionally done for a very recently run down zoo.