It is alright to eat leftovers in the morning but you need to refrigerate them properly. The leftover food stuff on the dining table should be transferred to a container with a lid and should be refrigerated immediately. Every minute that it is left lying on the kitchen counter the food would get contaminated by bacteria. It is safe to cook all foods thoroughly. All fresh vegetables and fruits must be thoroughly washed in running water to get rid of the pesticides sprayed on them. Undercooked chicken or beef could bring a lot of trouble for you. If you have raw meat on the kitchen counter or in the refrigerator it should never be left open. It is also a good thing to wash hands thoroughly before starting to cook. After cooking you need to tell your family members that all utensils must be washed in hot water with good detergents.