Subhadrika Sen
Salt: Is salt only added for taste? Yes that, and for making the dish last for a couple of days.
Vinegar: A common component of canned or tinned food, vinegar is a natural preservative.
Oil: Vegetable oil or mustard oil are very good preservatives. Remember, every bottle of achaar has loads of oil!
Lemon juice: Sprinkling lemon juice keeps the dish or item fresh. apart from adding the tang in salad dressing, it also keeps the ingredients fresh and cruchy for longer duration.