Food for the Future
{OUR ANSWER TO WORLD HUNGER}
Food preservation involves using certain mechanism to prevent food spoilage due to bacteria, fungi and other micro-organisms, as well as retarding the oxidation of fats that cause rancidity. Food preservation can also include processes that inhibit visual deterioration, such as the enzymatic browning reaction in apples after they are cut.
Although there are more than 20 preservation methods, we will focus on the 7 common types.
Drying
Drying reduces water concentration to prevent bacterial growth. Food can be dehydrated by various means: the Sun, a conventional oven, an electric dehydrator or a microwave oven (for herbs only). Drying, like other preservation methods, requires energy. Unless sun drying is possible, the energy cost of dehydrating foods at home is higher than for canning, and in some cases more expensive than freezing.
Electric Dehydrators. Reproduced from Canning and Preserving for Dummies, 2nd Edition. (n.d.)
Pasteurisation
In 1862, Louis Pasteur invented pasteurisation, used mainly for preserving liquid food. It is now used to prevent milk from spoilage by heating it at 70°C for 15 to 30 seconds to kill the bacteria and cooling it quickly to 10°C to prevent remaining bacteria from growing. Finally, it is stored in sterilized bottles in cold places.
Pasteurisation Process. Reproduced from Centrale Laitière Vallée d'Aoste site.
Refrigeration
It preserves food by slowing down the growth and reproduction of micro-organisms and the action of enzymes that cause food to rot. It is the most commonly used household appliance to prevent food from spoilage.
Refrigerator. Reproduced from Home Improvement Blog.
Food Preservation Techniques
Preservatives
Addition of preservatives includes pickling, adding salt, sugar and artificial food additives. Jam is made by boiling, sugaring and sealing the contents within an airtight jar. Boiling reduces fruit moisture content and kills bacteria, while sugaring prevents their regrowth and sealing prevents recontamination.
Salting of Fish. Reproduced from food24.com
Vacuum Packing
It stores food in an air-tight environment, stripping bacteria of oxygen needed for survival, slowing spoiling. Food can be cooked and then stored in vacuum packs for long periods. Many companies now package their food in vacuum packs as it allows ready-to-eat food to be kept fresh.
Vacuum-packed sausages. Reproduced from xjpack.cn
Freezing
It is commonly linked to refrigeration, provides large-volume, long-term storage for strategic food stocks held in case of national emergency. It is also a better form of food preservation compared to refrigeration as it inhibits bacteria. Freezing enables families to survive during winter as it stores large volumes of foodstuff that is not available during the winter.
Ice Cubes. Reproduced from iFood site.
Canning
Canning involves cooking food, sealing it in sterile cans or jars and boiling the containers to kill remaining bacteria. It was invented by Nicolas Appert. A pressure canner is used to ensure safe low-acid canned foods.
Canned Fruits and Vegetables. Reproduced from Old Fashioned Families.
