The caterer must purchase all food products from a licensed and inspected retail store or supplier. The caterer cannot guarantee the source or safe handling of any dish they do not prepare and may not be willing to provide this service. The caterer may choose to retain or dispose of all the leftovers so that the subsequent handling of the food is in a controlled environment. Preparation and serving of food should be under cover, such as in a tent. Seasonal conditions requiring the exclusion of flies and bees must also be considered.
References can sometimes recommend additional things to discuss with a particular caterer.