Celery does not stay fresh when it is stored in clear plastic bags, especially if the bags are sealed. Plastic bags trap ethylene gas, which causes the celery to spoil more quickly.
Consumers can keep celery fresh by wrapping it in aluminum foil. The foil protects the celery and keeps it from drying out, while still allowing the ethylene gas to escape. Consumers can also keep celery fresh by cutting up the different stalks and keeping them in a covered dish of clean, preferably filtered, water. Regardless of the container in which it's kept, celery should be kept in the refrigerator to maximize freshness.