Keep the lid closed as much as possible to slow down the melting of the ice and to maintain the internal temperature of the cooler. Keep foods that require constant access such as soft drinks and other non-perishable foods in another cooler. Return any leftovers to ice chests as soon as possible. Food sitting at outside temperatures more than two hours is not safe to eat. At 90 degrees or above, food should not sit out more than one hour.
Food spoils quickly at high temperature.
The few dollars of expense associated with the discarded food is far less that the expense, discomfort and threat to one's health with a case of food-borne illness. If insects are a problem, there are netting devices available to place over food to keep it bug-free. Keep insect sprays away from the food. If there are leftovers after the game, take precautions to ensure safety. There should still be ice in the cooler, and the food should be refrigerator cold.