Food Preservation Methods - Food Poisoning

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Food Preservation Definition

Food preservation is the procedure by which food is treated and handled to stop or slow down food spoilage, loss of quality, edibility or nutritional value and thus allow for longer food storage.

Preservation usually involves preventing bacteria, fungi (such as yeasts), and other micro - organisms from developing, as well as retarding the oxidation of rancid-causing fats.

Importance of Food Preservation

Food preservation stops the growth of micro - organisms (such as yeasts) or other micro - organisms (although some methods work by presenting benign bacteria or fungi into the food), and slows the oxidation of rancid-causing fats.

Methods of Preservation 

A number of food preservation techniques that can be used which can either prevent, delay or otherwise reduce food spoilage altogether. Preservatives can extend the shelf life of food and can last as long as it can be grown, stored, marketed and kept in the home of the customer for a reasonable period of time.

Preserving or producing nutritional value, texture and flavor is an important aspect of food storage methods, although some methods have drastically altered the character of the preserved foods. These changes have now been seen in many cases as desirable qualities, such as cheese, yogurt and pickled onions.

Drying

Drying is one of the most ancient techniques of food preservation which reduces water activity enough to prevent bacterial growth.

Refrigeration

Refrigeration preserves food by slowing down microorganism growth and reproduction and the action of enzymes that cause food to rot.

Freezing

It is also one of the most frequently used processes for preserving a wide range of foods, including prepared foods that in their unprepared state would not require freezing.

Salting

The salting or curing process removes moisture from the meat through an osmosis process. Meat is salted or cured with sugar, or a combination of the two. Nitrates and nitrites are also widely used to treat meat, leading to the distinctive pink color and inhibiting Clostridium botulinum.

Crystallization

Sugar is used to maintain fruits, either in fruit syrup such as apples, peaches, apricots, or in a crystallized form where the preserved material is cooked in sugar to the point of crystallization and the resulting product is then stored in dry place.

This method is used for the citrus (candied peel), angelica, and ginger skins. A alteration of this process creates glacé fruit, such as glacé cherries, in which the fruit is preserved in sugar but then extracted from the syrup and sold, preserving the fruit's sugar content and superficial syrup coating.

The use of sugar in brandy or other spirits is often combined with alcohol for preserving luxury products such as fruit. These should not be confused with spirits that are aromatised with fruit such as cherry brandy.

Smoking

Smoking is used to prolong the shelf - life of perishable food. This effect is achieved through the exposure of the food from burning plant materials such as wood to smoke. The meats and fish that have undergone curing are most commonly subjected to this method of food preservation.

Also smoked are fruits and vegetables such as paprika, cheeses, spices and ingredients for making drinks such as malt and tea leaves, but mostly for cooking or flavouring. It is one of the oldest methods of food preservation which probably emerged after cooking with fire evolved.

Additives

Additives to the preservative foods can be antimicrobial. These inhibit bacterial or fungal growth, including mold or antioxidant, such as oxygen absorbers, which inhibit the oxidation of food components. 

Preservatives

Adding preservatives is the chemical methods of food preservation. Conventional antimicrobial preservatives include calcium propionate, sodium nitrite, sodium nitrate, sulphites (sulfur dioxidepotassium hydrogen sulfite, sodium bisulfite, etc.) and disodium EDTA. BHA and BHT are antioxidants. 

Pickling

Pickling is a food preservation method used in an edible anti - microbial liquid. Pickling can be broadly divided into two categories: chemical pickling and pickling by fermentation.

Canning

Canning includes cooking food, sealing it in sterile canisters or pots, and boiling the containers as a method of sterilization to destroy or weaken any remaining bacteria. Foods have varying degrees of natural spoilage protection, and may require the final step in a pressure cooker. 

No preservatives are added to High - acid fruits like strawberries and only a short boiling period, while marginal fruits such as tomatoes require longer boiling and addition of other acidic components. Feeding stuffs with low acidity, such as vegetables and meats, require canning pressure.

Food preserved through canning or bottling is at immediate risk of spoilage after opening the can or bottle.

Other Types of Preservation may Include: 

Irradiation, jellying, jugging, , processing of pulsed electric fields, modified atmosphere, ground burial, biopreservation and high pressure.

FAQ (Frequently Asked Questions)

Q1: What are the 5 Methods of Food Preservation?

These are 5 Types of Food Preservation Methods:

  • Canning

  • Freezing.

  • Drying.

  • Fermenting. 

  • Pickling.

Q2: What is the Meaning of Food Preservation?

Ans: Food preservation is the method of food treatment and managing to stop or slow down food spoilage, quality loss, edibility or nutritional value and thus allow for longer food storage.

Q3: What are the Objectives of Food Preservation?

Ans: Food preservation stops the growth of micro - organisms (such as yeasts) or other micro - organisms (although some methods work by presenting benign bacteria or fungi into the food), and slows the oxidation of rancid-causing fats.