Chill condiments and beverages before placing them in coolers. Use separate coolers for beverages and food. Beverage coolers are opened more frequently than food coolers - the temperature inside a cooler rises each time it is opened. Transfer food directly from the refrigerator to the cooler. Add more ice, or less-perishable foods, such as peanut butter or fruit.
Temperatures remain more constant in a full cooler.
Transport coolers in the air-conditioned passenger compartment, not in the trunk. Keep coolers out of the sun, covered with a blanket. Open coolers only when necessary. Grill only the quantity of food that will be eaten. Transfer cooked meats and poultry to a clean serving plate.