A Memorial Day picnic can be a festive start to the summer season if you can avoid foodborne illness. Don't forget three important rules when packing your picnic. Keep hot foods hot, keep cold foods cold, and if in doubt about the safety of food, throw it out.
Temperature is important as well.
Hot foods should be kept at 140 degrees F or higher and cold foods at 40 degrees F or lower. It is important to keep hot and cold foods in separate coolers or containers. Use ice packs and a cooler for cold foods, and wrap hot foods in aluminum foil or an air tight container. Foods which contain meat, fish, poultry or dairy ingredients are most susceptible to foodborne illness, so store and serve them properly. Serve picnic foods right before eating and stow them away when the meal is finished.