A refrigerator keeps all foods safe to eat for four hours without electricity. Beyond that time, some, but not all foods remain safe to eat. Foods that should be discarded after four hours are meats, dairy, soft unprocessed cheeses, and prepared meals or leftovers.
Generally, condiments with high acidic content, hard cheeses, bakery items and produce can be kept for a longer time and discarded if they show changes in color or smell or the presence of mold. A freezer keeps foods safe to eat for 48 hours if full and 24 hours if partially full. It is also helpful to keep a thermometer in the refrigerator and important to refrain from opening refrigerator doors unnecessarily during a power interruption.