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are destroyed . A food that is sterile contains no bacteria . Unless sterilised and sealed , all food contains bacteria . Drying is a process that people have used for centuries . The removal of the moisture in the foodstuff inhibits the growth of bacteria , yeasts and mould . Cooling preserves food by slowing down the growth and reproduction of microorganisms and the action of enzymes that cause food to rot . Freezing food slows down decomposition by turning residual moisture into ice , inhibiting the growth of most bacterial species . Boiling liquid food items can kill any existing microbes , which is why we boil water
to purify it . Salting or curing draws moisture from a substance through a process of osmosis . Foodstuffs are cured with salt or sugar , or a combination of the two . We use sugar as a means of preservation , because sugar tends to draw water from the microbes ( plasmolysis ). This process leaves the microbial cells dehydrated , thus killing them . We preserve fruit by boiling and storing it in a syrup .
IN THE KITCHEN
Pickling is a method of preserving food in an edible anti-microbial liquid such as vinegar , alcohol , brine or vegetable oil . Smoking is used to lengthen the shelf life of perishable food items . This effect is achieved by exposing the food to smoke from burning plant materials such as wood . Smoke deposits a number of pyrolysis products on to the food , which aid in the drying and preservation of meats and other foods .
Bottling or home canning is the process of preserving food , in particular fruits , vegetables and sometimes meat , by packing them into glass jars and then heating the jars to kill the organisms that would create spoilage . Fermentation works through the use of specific microorganisms that combat spoilage from other lessbenign organisms . This process is used in the making of cheeses , wine and beer .
Bottling
Bagging for the freezer
Biltong and fuit dryer
Air drying herbs
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