METHOD OF PRESERVING FOOD

1. Drying

one of the most ancient food preservation techniques, which reduces water activity sufficiently to prevent bacterial growth.

2. Refrigeration

Preserves food by slowing down the growth and reproduction of micro-organisms and the action of enzymes which cause food to rot

3. Freezing

-is the process of chilling foods to at least 0 F.

-It can be used with all foods

-True freezing is not possible in the freezer compartment of your refrigerator where the temperature is typically much warmer, between 10 F to 32 F.

- Easy Method.

4.Vacuum packing

A vacuum environment, usually in an air- tight bag or bottle strips bacteria of oxygen needed for survival, slowing spoiling. Vacuum-packing is commonly used for storing nuts to reduce loss of flavor from oxidation.

5.Salting/Curing.

Salt draws water through Osmosis, Prague powder(NaNO2 + Salt) gives it a distinctive pink colour)

Example of food where you can use prague powder are Pork Tocino, Tapa or Cured Ham

7. Smoking

Chemical components from the smoke of burning wood:

Is a complementary process to curing that improves flavor and appearance and can also act as a drying agent

Most commonly subjected to this method of food preservation are meat  and fish  that have undergone curing

Fruits and vegetables like paprika, cheese ,spices, and ingredients for making drinks such as malt  and tea leaves are also smoked, but mainly for cooking  or flavoring  them.

It is one of the oldest food preservation methods, which probably arose after the development of cooking with fire.

8. ArtificiaL Food Additives

Common antimicrobial preservatives include calcium propionate, sodium nitrate, sodium nitrite, sulfites (sulfur dioxide, sodium bisulfite, potassium hydrogen sulfite, etc.) and disodium EDTA. Antioxidants include BHA and BHT. Other preservatives include formaldehyde (usually in solution), glutaraldehyde (kills insects), ethanol and methylchloroisothiazolinone.

9. Jellying

Food may be preserved by cooking in a material that solidifies to form a gel. Such materials included gelatine,agar, maize,  flour, and  arrowroot flour.

10.Irradiation ( exposure to X Rays, gamma rays)

Irradiation is used to reduce pathogens, increase shelf life, eliminate pests, increase juice yield, [citation need ] delay sprouting, and improve re-hydration

It is used to as delay the ripening of fruits and the sprouting of vegetables by slowing down the enzymatic action in food

  In Austria, Germany, and many other countries of the European Union only dried herbs, spices, and seasonings can be processed with irradiation and only at a specific dose, while in Brazil all foods are allowed at any dose

11. High Pressure processing

Is a method of preserving and sterilizing food, in which a product is processed under very high pressure, leading to the inactivation of certain microorganisms and enzymes in the food .

This technique is now used there to preserve fish and meats, salad dressing, rice cakes, and yoghurt. An early use of pascalization in the United States was to treat guacamole. It did not change the guacamole's taste, texture, or color, but the shelf life of the product increased to thirty days, from three days without the treatment.

 However, some treated foods still require cold storage because pascalization does not stop all enzyme activity caused by protein, some of which affects shelf life

12.Burying in the Ground

(lack of light, oxygen,lowpH,cool temp, dessicants in soil)

Century Eggs  are created by placing eggs in alkaline mud (or other alkaline substance), resulting in their "inorganic" fermentation through raised pH instead of spoiling .

13. Biopreservation (addition of LAB)

In biopreservation, beneficial bacteria are used to prevent food spoilage and get rid of harmful pathogens. Lactic acid bacteria (LAB) are probably the most commonly used due to their unique properties and because they are harmless to humans. As LABs compete for nutrients with other bacteria, they release antimicrobials that stop spoilage and inhibit the growth of potentially harmful pathogens.

14. Pickling

Can be categorized in two categorize:

a. Chemical (brine,vinegar, oil)

- the food is placed in an edible liquid that inhibits or kills bacteria and other micro-organisms. Typical pickling agents include brine (high in salt ), vinegar, alcohol , and vegetable oil , especially olive oil  but also many other oils. Common chemically pickled foods include cucumber, pepper, cornedbeef, jeering , and eggs , as well as mixed vegetables.

b. Fermentation (lactic acid produced by the food itself)

-this are foods produced or preserved by the action of microorganisms. In this context, fermentation typically refers to the fermentation of sugar to alcohol using yeast, but other fermentation processes involve the use of bacteria such as lactobacillus, including the making of foods such as yogurt and sauerkraut.

15. Addition of Lye

-NaOH prevents bacterial growth, saponifies fats

-Lye is used to cure many types of food, including lutefisk, olives (making them less bitter), canned mandarin oranges, homminy,lye rolls, century eggs and pretzels . It is also used as a tenderizer in the crust of baked Cantonese moon cakes, in “zongs” (glutinous rice) dumplings wrapped in bamboo leaves), in chewy southern Chinese noodles popular in Hong Kong and southern China, and in Japanese ramen noodles.

6.Canning and Bottling

is the process of heating the product at a specified temperature for a specific length of time (pasteurizing)

Vacuum sealing the pasteurized food in special glass jars.