METHODS OF PRESERVATION OF MATERIALS
- Photocopying using photocopying machines.
- Chilling and Freezing – Bacteria and yeast grow best at specific temperatures, usually between 40-140ºF. By lowering the temperature below 40ºF their metabolic and reproductive action is significantly slowed. While this may not actually kill the bacteria and yeast, it does slow the spoilage process. Although freezing food has been used in colder climates for hundreds of years, the expansion of electricity and home appliances in the early and mid-20th century greatly expanded the use of freezing as a food preservation method.
- Canning – Canning preserves materials like food by removing the oxygen needed for most microorganisms to grow. Because some organisms are able to flourish in the absence of oxygen, canning is usually combined with a second factor that inhibits microbial growth, like acid or salt (usually in the form of a brine). Canning became a popular method of food preservation with the industrial revolution and is still quite popular today.
- Dehydrating – Most microorganisms also require moisture to grow, so removing the moisture from perishables is a very effective method of preservation. The key to dehydration is to complete the process faster than the spoilage occurs. Evaporation is usually quickened with the addition of moderate heat, sometimes provided by natural sunlight. The added bonus of sunlight are ultra violate rays, which also serve to kill microbes. Modern methods of dehydration use circulating air that is heated just enough to promote dehydration without “cooking” the food. Dehydration is the method of food preservation used for meat jerky, dried fruit or fruit leathers, and herbs.
- Fermenting – Fermenting is another ancient technique of materials preservation that has remained popular to this day. The popularity is most likely attributed to the unique flavor that is accrued through fermentation. Fermentation itself is a form of perishables spoilage, but when the microorganisms are tightly controlled, it can produce desirable effects and provide safeguards against harmful organisms. The bacteria or yeast used in the fermentation process produce acid as a byproduct, which acts to prevents other, potentially harmful bacteria from thriving. As an added bonus, many of the organisms used to ferment foods are also healthy additions to the natural flora of the human gastrointestinal tract. Both sauerkraut and kimchi are examples of the use of fermentation to preserve cabbage.
- Salting – Salting preserves materials by removing the moisture and creating an environment unsuitable for microbial growth. Very few bacteria grow in high salt solutions, so simply adding a very high amount of salt can be an effective method of preservation.
- Custom Protective Enclosures – Custom protective enclosures provide books with structural support and protection from dust, light, and mechanical damage. Detailed information on boxes can be found in NEDCC’s forthcoming leaflet 4.5 Custom Protective Enclosures. For the best level of protection, enclosures should be constructed of permanent, durable materials and custom made to fit the book’s dimensions exactly. Enclosures come in many varieties and each has its strengths: drop-spine boxes, phased boxes, wrappers, slipcases, book shoes, dust jackets, and pamphlet binders. Candidates for protective enclosures include:
- Volumes with fragile bindings of special value that should be retained in their present condition;
- Damaged books that have low value or are rarely used and do not warrant treatment or repair of the binding;
- Thin, small, fragile, limp, or oddly-shaped volumes; and
- Parchment bindings.
- Acidification – Many foods last longer if they are simply dunked in a bath of vinegar. Just as vinegar rids dirty clothes and kitchen countertops of infectious germs, it can be put to the same— though tastier—use with fruits, vegetables and herbs. The most famous vinegar-preserved foods are cucumbers (though some cucumber pickles are actually fermented), but many other foods are delicious in vinegar, too—turnips, beets, radishes, carrots, leeks, kale, garlic scapes, Swiss chard, green beans, cauliflower, zucchini, peppers, asparagus, cantaloupe and green tomatoes are just some of the options that are delicious when pickled. From balsamic and apple cider to rice and champagne, a wide world of vinegar flavors awaits. The recipe above provides a supersimple way to preserve fresh cucumbers using acidification.
- Vacuum-packing: – Vacuum-packing process leads to storing food in an airtight environment, like a bag or bottle.
- Irradiation: – It is also known as cold pasteurization. It helps in keeping the molds and bacteria’s away. This can help in preserving vegetables and fruits in a jar without ripening or any spoilage. 11 Ultra heating -This entails heating the material at very high temperature to kill micro organisms
- Storage in refrigerators
- Storage of materials eg information drives such hard drives ,flash disks, floppy disks, google drives, cloud storage
- Storage in strong rooms safe boxes
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