food preservation is the process of treating and handling food to stop or greatly slow down spoilage

8/9/2019 Food Preservation is the Process of Treating and Handling Food to Stop or Greatly Slow Down Spoilage

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Food preservation is the process of treating and handling food to stop or greatly slow downspoilage (loss of quality, edibility or nutritive value) caused or accelerated by micro-organisms.

Some methods, however, use benign bacteria, yeasts or fungi to add specific qualities and to preserve food (e.g., cheese, wine). Maintaining or creating nutritional value, texture and flavour

is important in preserving its value as food. This is culturally dependent, as what qualifies as

food fit for humans in one culture may not qualify in another culture.

Preservation usually involves preventing the growth of bacteria, fungi, and other micro-

organisms, as well as retarding the oxidation of fats which cause rancidity. It also includes processes to inhibit natural ageing and discolouration that can occur during food preparation

such as the enzymatic browning reaction in apples after they are cut. Some preservation methodsrequire the food to be sealed after treatment to prevent recontamination with microbes; others,

such as drying, allow food to be stored without any special containment for long periods.

Common methods of applying these processes include drying, spray drying, freeze drying,freezing, vacuum-packing, canning, preserving in syrup, sugar crystallisation, food irradiation,

and adding preservatives or inert gases such as carbon dioxide. Other methods that not only helpto preserve food, but also add flavour, include pickling, salting, smoking, preserving in syrup or

alcohol, sugar crystallisation and curing.

DRYING One of the oldest methods of food preservation is by drying, which reduces water activity

sufficiently to prevent or delay bacterial growth.[citation needed ]

Drying also reduces weight, making

food more portable. Most types of meat can be dried; a good example is beef biltong. Many

fruits can also be dried; for example, the process is often applied to apples, pears, bananas,

mangoes, papaya, apricot, and coconut. Zante currants, sultanas and raisins are all forms of

dried grapes. Drying is also the normal means of preservation for cereal grains such as wheat,



maize, oats, barley, rice, millet and rye.

FREEZING Freezing is also one of the most commonly used processes commercially and domestically for

preserving a very wide range of food including prepared food stuff s which would not have

required freezing in their unprepared state. For example, potato waffles are stored in the

freezer, but potatoes themselves require only a cool dark place to ensure many months'

storage. Cold stores provide large volume, long-term storage for strategic food stocks held in



case of national emergency in many countries.

Vacuum-packing Vacuum packing is a method of storing food and presenting it for sale. Appropriate

types of food are stored in an airless environment, usually in an air-tight pack or bottleto prevent the growth of microorganisms. The vacuum environment removes

atmospheric oxygen, protecting the food from spoiling by limiting the growth of aerobic bacteria or fungi, and preventing the evaporation of volatile components. Vacuum

packing is commonly used for long-term storage of dry foods such as cereals, nuts,cured meats, cheese, smoked fish, coffee, and crisps. It is also for storage of fresh foods

such as vegetables, meats, and liquids such as soups in a shorter term because vacuumcondition cannot stop bacteria from getting water which can promote their growth.

Vacuum packaging food can extend its life by up to 3-5 times.

Vacuum packing is also used to reduce greatly the bulk of non-food items. For example,

clothing and bedding can be stored in bags evacuated with a domestic vacuum cleaner or a dedicated vacuum sealer. This technique is sometimes used to compact household



waste, for example where a charge is made for each full bag collected. Vacuum packingcan be used to reduce bulk of inflatable items as well.

Vacuum packaging products using plastic bags, canisters, bottles, or mason jars areavailable for home use.

Vacuum packaging delicate food items can be done by using an inert gas kit, typically

available on chamber vacuum sealers. After air has been removed, an inert gas (such asnitrogen) is added to maintain the preservation of packaged food while preventing

damage. An example of inert gas for packaging delicate foods is potato chips.

SALTING Salting or curing draws moisture from the meat through a process of osmosis. Meat is cured

with salt or sugar, or a combination of the two. Nitrates and nitrites are also often used to cure

meat and contribute the characteristic pink color, as well as inhibition of Clostridium

botulinum.



P

ICKLING Pickling is a method of preserving food in an edible anti-microbial liquid. Pickling can

be broadly categorized as chemical pickling (for example, brining) and fermentation pickling (for example, making sauerkraut).In chemical pickling, the food is placed in an

edible liquid that inhibits or kills bacteria and other micro-organisms. Typical picklingagents include brine (high in salt), vinegar , alcohol, and vegetable oil, especially olive

oil but also many other oils. Many chemical pickling processes also involve heating or boiling so that the food being preserved becomes saturated with the pickling agent.

Common chemically pickled foods include cucumbers, peppers, corned beef , herring,

and eggs, as well mixed vegetables such as piccalilli, chow-chow, giardiniera, andachar .In fermentation pickling, the food itself produces the preservation agent, typically by a process that produces lactic acid. Fermented pickles include sauerkraut, nukazuke,

kimchi, surströmming, and curtido. Some chemically pickled cucumbers are alsofermented.In commercial pickles, a preservative like sodium benzoate or EDTA may

also be added to enhance shelf life.

CANNING&BOTTLING Canning involves cooking food, sealing it in sterile cans or jars, and boiling the

containers to kill or weaken any remaining bacteria as a form of sterilization. It wasinvented by Nicolas Appert [1]. Foods have varying degrees of natural protection against

spoilage and may require that the final step occur in a pressure cooker . High-acid fruitslike strawberries require no preservatives to can and only a short boiling cycle, whereasmarginal fruits such as tomatoes require longer boiling and addition of other acidic

elements. Low acid foods, such as vegetables and meats require pressure canning. Food preserved by canning or bottling is at immediate risk of spoilage once the can or bottle

has been opened.Lack of quality control in the canning process may allow ingress of water or micro-organisms. Most such failures are rapidly detected as decomposition

within the can causes gas production and the can will swell or burst. However, there



have been examples of poor manufacture (underprocessing) and poor hygiene allowingcontamination of canned food by the obligate anaerobe Clostridium botulinum, which

produces an acute toxin within the food, leading to severe illness or death. Thisorganism produces no gas or obvious taste and remains undetected by taste or smell. Its

toxin is denatured by cooking, though. Cooked mushrooms, handled poorly and then

canned, can support the growth of Staphylococcus aureus, which produces a toxin that isnot destroyed by canning or subsequent reheating.

BOILING Boiling, a type of phase transition, is the rapid vaporization of a liquid, which typically

occurs when a liquid is heated to its boiling point, the temperature at which the vapor pressure of the liquid is equal to the pressure exerted on the liquid by the surroundingenvironmental pressure. Thus, a liquid may also boil when the pressure of the

surrounding atmosphere is sufficiently reduced, such as the use of a vacuum pump or athigh altitudes. Boiling occurs in three characteristic stages, which are nucleate,

transition and film boiling . These stages generally take place from low to high surfacetemperatures, respectively.

COOLING



Cooling is the transfer of thermal energy via thermal radiation, heat conduction or

convection.

SMOKING

Smoking is a practice in which a substance, most commonly tobacco, is burned and the smoke tasted or inhaled. This is primarily practised as a route of administration for recreational drug

use, as combustion releases the active substances in drugs such as nicotine and makes themavailable for absorption through the lungs. It can also be done as a part of rituals, to induce

trances and spiritual enlightenment. The most common method of smoking today is throughcigarettes, primarily industrially manufactured but also hand-rolled from loose tobacco and

rolling paper . Other smoking tools includes pipes, cigars, hookahs and bongs.Smoking is one of the most common forms of recreational drug use. Tobacco smoking is today by far the most

popular form of smoking and is practiced by over one billion people in the majority of all humansocieties. Less common drugs for smoking include cannabis and opium. Some of the substances

are classified as hard narcotics, like heroin and crack cocaine, but the use of these is very limitedas they are often not commercially available.The history of smoking can be dated to as early as

5000 BC, and has been recorded in many different cultures across the world. Early smokingevolved in association with religious ceremonies; as offerings to deities, in cleansing rituals or to

allow shamans and priests to alter their minds for purposes of divination or spiritualenlightenment. After the European exploration and conquest of the Americas, the practice of



smoking tobacco quickly spread to the rest of the world. In regions like India and SubsaharanAfrica, it merged with existing practices of smoking (mostly of cannabis). In Europe, it

introduced a new type of social activity and a form of drug intake which previously had beenunknown.Perception surrounding smoking has varied over time and from one place to another;

holy and sinful, sophisticated and vulgar, a panacea and deadly health hazard. Only relatively

recently, and primarily in industrialized Western countries, has smoking come to be viewed in adecidedly negative light. Today medical studies have proven that smoking tobacco is among theleading causes of many diseases such as lung cancer , heart attacks, erectile dysfunction and can

also lead to birth defects. The inherent health hazards of smoking have caused many countries toinstitute high taxes on tobacco products and anti-smoking campaigns are launched every year in

an attempt to curb tobacco smoking.

WAXINGWaxing is a method of semi-permanent hair removal which removes the hair from the root. Newhairs will not grow back in the previously waxed area for two to eight weeks. Almost any area of



the body can be waxed, including eyebrows, face, bikini area, legs, arms, back , abdomen andfeet. There are many types of waxing suitable for removing unwanted hair.Waxing is

accomplished by spreading a wax combination thinly over the skin. A cloth or paper strip is then pressed on the top and ripped off with a quick movement against the direction of hair growth.[1]

This removes the wax along with the hair. Another method utilizes hard wax (as opposed to strip

wax). In this case, the wax is applied somewhat thickly and with no cloth or paper strips. Thewax then hardens when it cools, thus allowing the easy removal by a therapist without the aid of cloths. This waxing method is very beneficial to people who have sensitive skin

Pastearization

Pasteurization is a process which slows microbial growth in food. The process was named after its creator, French chemist and microbiologist Louis Pasteur . The first pasteurization test was

completed by Louis Pasteur and Claude Bernard on April 20, 1864. The process was originally

conceived as a way of preventing wine and beer from souring.[1]

Pasteurization is not intended to destroy all pathogenic micro-organisms in the food or liquid.Instead, pasteurization aims to reduce the number of viable pathogens so they are unlikely to

cause disease (assuming pasteurization product is stored as indicated and consumed before itsexpiration date). Commercial-scale sterilisation of food is not common because it adversely

affects the taste and quality of the product. Certain food products are processed to achieve thestate of commercial sterility.

[2]

food preservation is the process of treating and handling food to stop or greatly slow down spoilage

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