Which of the following is commonly used as a food preservative?

Sodium benzoate

The correct answer is option 1. Sodium benzoate.

Let us look at each of the provided options:

1. Sodium Benzoate:

Sodium benzoate is a widely used food preservative. It is effective in acidic conditions (pH below 4.5), making it suitable for preserving acidic foods and beverages such as soft drinks, fruit juices, pickles, and sauces. It inhibits the growth of bacteria, yeast, and fungi.

2. Potassium Benzoate:

Potassium benzoate is also used as a food preservative, similar to sodium benzoate. However, it is less common compared to sodium benzoate.

3. Terephthalic Acid:

Terephthalic acid is not used as a food preservative. It is mainly used in the production of polyethylene terephthalate (PET) plastics and polyester fibers.

4. Acetic Acid:

Acetic acid, commonly found in vinegar, is used as a preservative in some foods, especially pickles. However, its primary role is as a condiment and flavoring agent rather than a general food preservative.

While potassium benzoate can also be used as a food preservative, sodium benzoate is the more commonly used preservative among the options provided. Terephthalic acid is not used as a food preservative, and acetic acid, while having preservative properties, is more commonly used as a flavoring agent. Therefore, sodium benzoate is the most appropriate answer.

Therefore, the correct answer is Sodium benzoate.