Which of the following are food preservatives?

Salt, sodium nitrite, spices and vinegar

The correct answer is option 1. Salt, sodium nitrite, spices and vinegar.

Food preservatives are substances added to food to prevent spoilage and increase their shelf life by inhibiting the growth of microorganisms (such as bacteria, fungi, and molds) or slowing down chemical changes that occur naturally. The correct option includes commonly used food preservatives:

1. Salt (Sodium Chloride):  Salt is a traditional and widely used preservative. It works by drawing water out of microorganisms, thereby inhibiting their growth. It is commonly used in pickling and curing processes.

2. Sodium Nitrite: Sodium nitrite is used primarily in preserving meat and fish products. It inhibits the growth of bacteria, particularly Clostridium botulinum, which can cause botulism. It also imparts a characteristic color and flavor to cured meats.

3. Spices: Various spices, such as garlic, cinnamon, cloves, and others, have antimicrobial properties and can be used as natural preservatives. They not only add flavor but also contribute to the preservation of certain foods.

4. Vinegar: Vinegar, especially acetic acid present in it, acts as a preservative by creating an acidic environment that inhibits the growth of bacteria and molds. It is commonly used in pickling and as a condiment.

The other options mentioned (gypsum, soda, methyl alcohol, and formic acid) are not commonly used as food preservatives:

Gypsum: Gypsum is calcium sulfate dihydrate and is not used as a food preservative. It is sometimes used as a coagulant in tofu production.

Soda: The term "soda" is broad, and it could refer to various substances like baking soda (sodium bicarbonate), which is not a typical food preservative.

Methyl Alcohol: Methyl alcohol (methanol) is not used as a food preservative. In fact, it is toxic and should not be ingested.

Formic Acid: While formic acid is used in some industrial processes, it is not a common food preservative. It is not generally recognized as safe for direct addition to food.

In summary, salt, sodium nitrite, spices, and vinegar are commonly employed food preservatives due to their effectiveness in preventing spoilage and enhancing the safety of food products.