Bacteria are discourage to grow in acids and citric acid boosts the acidity. So, Citric acid is in use as a preservative. Its use is in various food items like confectionery like candies, jellies, jams, canned food. In juices or beverages as well as in meat products. Its powder form is also to make sour flavors.
Citric Acid anhydrous Belgium is available at Humayun Wellchem Trading Concern in Pakistan.