Final answer:
Acids are added to foods to inhibit microbial growth and extend shelf life by creating an environment where spoilage organisms cannot survive. Examples of such foods include processed cheeses, pickles, and soft drinks.
Step-by-step explanation:
The addition of acid can be used to preserve foods by inhibiting microbial growth, which minimizes spoilage. This is because many food spoilage organisms are unable to survive in an acidic environment.
Certain acids, such as benzoic, propionic, and sorbic acids, can kill microorganisms that lead to food spoilage, and they are particularly effective as the pH of the food decreases. These preservatives are non-toxic, flavorless, and readily metabolized by humans, making them suitable for use in food preservation.
Three examples of foods where acids are added as preservatives include:
- Processed cheeses, where calcium and sodium propionate may be used
- Pickles, which often contain sodium benzoate to inhibit microbial growth
- Soft drinks, which may contain sodium or potassium sorbate to extend shelf life