How To Preserve Food Against Bacteria - For A Longer Life
Food preservation is an important aspect of the food industry. So, how to preserve food against bacteria for a longer life?
It involves methods of processing food to preserve its freshness and nutrition. This is done by slowing down growth of micro-organisms that can spoil food at the same time preserving the texture and nutrition of food. There are several ways one can do this.
Freeze Dried Foods: This method removes the water but not the flavor and just like the frozen food retain the nutritional content and fresh food taste. Unlike the dehydrated foods they do not shrink or shrivel up but maintain their shape and texture. Just add a little water and they come back to their original texture. Commonly used by food companies for having a good shelf life and convenience like canned or preserved foods. They weigh less because of less water content and are also not that easily perishable or susceptible to spoilage mainly because of the removal of moisture and oxygen from them.
Canning: This method of preserving food has been in vogue since 19th century. Food is boiled to destroy bacteria and sealed in the container or jars. Foods with low acidity need sterilization under high temperature, specially meats, seafood, poultry and dairy products. Canned foods are very popular due to its high shelf life and transportability. This is one of the preferred methods for transferring food in the army even today. Some studies have indicated that the canned food carry as much nutrition as the fresh food with not much loss.
Pickling: This is an anaerobic fermentation method also called as brining or corning used by preserving the vegetables or fruits in salt water. Ph of less than 4.6 is enough to kill bacteria. Garlic, cinnamon, mustard is used to add to the pickled vegetables to add flavor. Salting the vegetables to draw out their water and the natural fermentation by lactic acid bacteria brings on the acidity.
Vacuum Packing: Vacuum-packing stores the food in a vacuum environment. The container is made air-tight stripping it of oxygen needed for the bacteria, which in turn slows down the spoilage. Nuts are stored this way to reduce the loss of flavor by oxidation.
Artificial Food Additives: There are also anti-microbial agents that can be added to inhibit bacteria and fungi also antioxidants that inhibit oxidation of foods. Some of the examples of such preservatives are calcium propionate, sodium nitrate, sulfites etc.
Irradiation: Exposure of food to ionizing radiation either by high energy electrons or X-rays from accelerators or Gamma rays. This treatment kills bacteria, molds and insects which in turn reduces spoilage at the same time sterilizing it. Spices and condiments are subjected to this treatment although now even fresh fruits are included for fly quarantines. 500,000 tons of foods are irradiated in over 40 countries now.
There are several other methods such as Drying, Freezing, Sugaring, adding Lye, Bottling, Jellying, Irradiation, Pulsed electric field processing, High pressure food preservation, burying underground, Heat treating, Dehydrating and refrigeration.