Having chopped carrots, celery and onions on hand in the fridge is so convenient and can be a major timesaver. Mirepoix — a combination of chopped carrots, celery and onions— is a staple in many recipes and is used to flavor soups, stocks, sauces and other cooked dishes.
Properly stored, chopped carrots, celery and onions will keep well for at least a week in the fridge. Wash/peel the veggies thoroughly before chopping. Wrap the chopped veggies tightly in plastic wrap or aluminum foil, or place in a covered container or sealed plastic bag.