Most cooked leftovers are good 3-4 days in a sealed container at 40°F or below. Soups and stews hold up well, while seafood or cream-sauce dishes are best inside 2 days. When reheating, get food to 165°F all the way through.

Usually, yes. Best-by and use-by dates are about quality, not safety, so they mark the maker's guess at peak flavor rather than a hard cliff. Dry goods, canned foods, and dairy often work days to weeks past that date, so lean on your senses.

No. Freezing stops bacterial growth but doesn't kill the bacteria already there. When food thaws, whatever was present wakes back up, which is why you thaw in the fridge or cold water and cook to safe internal temperatures.

A sour or ammonia-like smell is the clearest sign. Slimy or tacky surface texture, even after rinsing, means it's gone. Color alone isn't reliable, since beef turns gray-brown from oxygen and can still be fine, so trust smell and texture together.

Raw eggs in the shell crack as they expand. High-water vegetables like cucumber, lettuce, and celery turn to mush, soft cheeses like brie and ricotta separate, and cooked pasta or potatoes go grainy. Mayo-based salads break down completely.