Final answer:
The main principle behind food preservation methods is to ensure safety and freshness by slowing down spoilage and preventing microbial growth. Techniques vary from the use of preservatives, antioxidants, and methods that alter osmotic pressure, to fortification with vitamins and minerals.
Step-by-step explanation:
The main principle behind the food preservative method is to maintain or improve the safety and freshness of food. This is achieved by using techniques and substances that slow the spoilage caused by microbes such as mold, air, bacteria, fungi, or yeast. These preservative techniques help in controlling contamination that could lead to foodborne illnesses and maintain the quality of food by preventing the development of rancid flavors or off-flavors in fats and oils. Similarly, antioxidants prevent cut fresh fruits from browning when exposed to air.
Preservatives also play a critical role in improving or maintaining the nutritional value of food. They assist in fortification and enrichment, thereby reducing malnutrition. An example includes the addition of vitamins and minerals to food products. Moreover, certain preservatives work on the principle of osmotic pressure, creating an environment that dehydrates bacteria, as seen in the use of high concentrations of sugar in jams and jellies, or salt in preserved meats like ham and bacon.
Common chemical preservatives include substances such as sorbic acid, benzoic acid, and propionic acid, which are used to control mold growth in acidic environments. Natural chemical food preservatives like nisin, produced by microbes, also contribute to this process by disrupting cell wall production of bacteria. Other preservatives include antioxidants, such as BHA and BHT, which prevent food deterioration due to oxygen exposure.