You have to declare all food items on your Customs entry form. Failure to do so, can result in confiscation and if you have restricted products the possibility of a fine of up to $1,000. Restricted products are fresh fruit and vegetables, meat and meat products including such products as soups etc., and dairy products. Every Customs official, in any country, has the right to search your baggage and luggage.
BTW: I think that you are only allowed one litre of alcohol irrespective of the alcoholic content. So 1 litre of whiskey = 1 litre of cider = 1 litre of wine!!
Crisps, snack foods like hola hoops, chocolate (watch out for the alcoholic content of chocolate liqueurs tho') swwet/candy and jam/preserves are permitted.