Correct Option
The correct option is (c) 1 and 3 only.
Explanation
Food preservation involves the use of physical or chemical agents to inhibit the growth of microorganisms (bacteria, yeasts, and molds), thereby increasing the shelf life of food products. In the food industry, specific chemical preservatives and natural substances are permitted based on safety standards.
Statement-wise Analysis
- Statement 1 is Correct: Sodium benzoate is one of the most common chemical preservatives used in acidic foods such as jams, squashes, and fruit juices. It inhibits the growth of yeast, mold, and bacteria by disrupting their cellular metabolism.
- Statement 2 is Incorrect: Sulphuric acid is a strong, corrosive mineral acid used in industrial applications like battery manufacturing and fertilizer production. It is toxic and corrosive to human tissues and is never used as a food preservative. Organic acids like citric acid or acetic acid are used instead.
- Statement 3 is Correct: Sugar acts as a natural preservative in jams, jellies, and squashes. It works by reducing the moisture content (water activity) of the food through osmosis, which creates an environment where bacteria and other microbes cannot survive or reproduce (plasmolysis).
Key Takeaway
Sodium benzoate and sodium metabisulphite are common chemical preservatives, while sugar, salt, and vegetable oil serve as natural preservatives by altering the osmotic environment or blocking air contact.