Methods of Food Storage and Preservation | Importance of Food Storage

Methods of Food Storage and Preservation
Methods of Food Storage and Preservation

Food Storage

Food must be stored under right conditions so that it remains safe till it is cooked served and consumed. Food items have different shelf life .These products need to be stored as per set guidelines for each of them. The nature of food item will’ decide how it should be stored.

Methods of Food Storage and Preservation
Methods of Food Storage and Preservation

There are different raw materials used in a kitchen. Some of them are bought raw as meats, milk’ and milk products, vegetables and fruits etc. Canned and frozen food is also used in the kitchen. Cereals, pulses and legumes is another category which comes in kitchen for production of dishes.

Storage of all the foods should be done as per specification of each category.

Heat Treated Foods:
Some foods are treated with high heat to either kill or reduce the micro-organism which may lead to food poisoning.  Such products are e1″her Sterilized or Pasteurized before they are send to market for consumption. We know that spoilage micro-organisms can with stand higher temperatures for longer periods than pathogenic organism. Sterilization means a process of high heat application where all the micro-organism and their spores are destroyed. Pasteurization on means a milder heat treatment which Will reduce the number of spoilage microorganism and destroy all the Pathogenic ones. Ultra high treatment (LIHT) destroys all bacteria but not their spores. By law packed milk, ice cream etc. either pasteurized, UHT treated or sterilized before they are sold.

Canned foods are sterilized so that they can be stored for a long period of time at normal room temperature before they are opened. Once they are opened they should be removed from the can and stored under refrigeration.

Date of Manufacturing and Batch Number labeling on packed food material is” must by law. Apart from date of Manufacturing BEST BEFORE’ time should be mentioned. Some of the products are good; only if they are used with m’ a one, three, six or nine month from the date of manufacturing.

Special Storage Instructions are also written on such packs eg. Store in a refrigerator.

Food Storage at Low Temperature:
All food that supports bacteria growth must be kept in the refrigeration for short term storage. These include:

1. Raw Meats
2. Raw Poultry
3. Fresh Fish and Shellfish
4. Cooked meats, fish or foods containing them as ingredients e.g. soups, stocks etc.
5. Milk, Cheese, Fresh Cream, Eggs or combination of them e.g. cakes, puddings
6. Cooked rice
7. Canned products after they are open.

Temperature inside the Fridge or Refrigerator:
It should be kept in between 1*C  to 4*C Check the temperature inside the fridge with thermometer if required. Most of the micro-organism are inactive at this temperature be they are not chilled. They do grow in the fridge too but at a very normal rate as compared 1f’ they are left at room temperature. That is why food if kept for many days m’ the fridge also get contaminated. The recommended storage duration for some food items are:

Care should be taken when storing food stuff in the refrigerator:

1. Keep the refrigerator m’ a Well ventilated place so that hot air from the condensers of the refrigerator are replaced with cool air.
2. Do not keep the doors open for a long time as the temperature may use’ to 10*C if the door is opened for 20 seconds.
3. Cool all the food before placing it in the refrigerator otherwise it may raise the temperature of the refrigerator.
4. Allow cold air to circulate throughout the fridge by keeping the food stuff at a little distance and away from the air vents.
5. Defrosting of fridge is must at a regular interval for keeping the cooling coils free of ice for effective cooling.

Cross-contamination
Ideally, raw food should be kept in a separate refrigerator from high-risk foods so that cross-contamination cannot occur. If only one refrigerator is available, the positioning of the foods should be carefully planned. Raw food must always be placed at the bottom of the refrigerator, with cooked food above it, so that any contaminated liquids from raw food cannot drip on to food that will not be cooked again.

food preservation methods
food preservation methods

Food should be covered while in the refrigerator to prevent cross-contamination, drying out and absorption of absorption. if cling film is used for this purpose, it should be placed over the food when it is cold. If the food is still warm, condensation collects on the food and extra moisture accelerates the growth of spoilage bacteria and moulds. Cling film should not be allowed to touch the food it is covering and should not be used to wrap foods, particularly those that have high fat content, e.g., cheese.

Stock Rotation
Most foods now carry a ’best before’ or a ’use by’ date. Any foods that do not carry such a date should be coded when they are put in the refrigerator to ensure effective stock rotation. Older food must always be used first and any food that has been stored longer than the recommended time should be destroyed.

Cleaning
The refrigerator must be kept clean any spills wiped up immediately. The inside surface should be washed regularly with weak solution of sodium bicarbonate.

Refrigerator display cabinets
In many catering establishment, refrigerator with glass doors are used to display food such as desserts and cream cakes. It is’ very important to check the temperature inside such cabinets regularly (several times a day on hot sunny days) to ensure that it does not rise” above 4°C. If the glass door is exposed to sunlight, it will allow heat to build up m’ the same way as it does m‘ a greenhouse. In addition, the fluorescent tubes used for display lighting will also tend to increase the temperature.

Chillers
Large catering premises may have a ’walk in chilling room that contains a refrigeration unit and a fan to circulate the air, Small chillers are also available. Chillers are used to reduce the temperature of large volumes of meat or other food to 15°C or below within’ 1 1/2 hour of cooking. The food can then be transferred to a refrigerator without a risk of increasing the temperature of the refrigerator significantly.

Freezers
Freezers are widely used in catering premises, as well as m’ the home, for long-term, low-temperature storage of food. The majority of bacteria will survive the freezing process and can remain dormant for months or years in the frozen food, although they are unable multiply. Freezing therefore cannot improve the quality of contaminated food, so only fresh, good quality food should be put in’ a freezer.

When frozen food is thawed, any dormant bacteria start to grow and multiply again when the temperature reaches the danger zone (5°C 63 C), so it is important to thaw food in correct way.

Operating temperature
A star marking system has been devised to indicate the temperature  a freezer or ‘ the frozen food storage compartment of a refrigerator. A four star symbol distinguishes a true freezer from appliances that are only designed to store frozen food. The operation temperature of a four star freezer 15′ also 48°C, but in‘ addition to its storage use it is capable of freezing fresh food without affecting the temperature of the frozen food 1n’ the rest of the freezer.

Storage times
The bacteria that cause food poisoning cannot multiply m’ or on frozen food, so provided that the temperature of the freezer 15′ maintained at -18 C there is’ no longer danger of frozen food becoming a health hazard, however long it is stored. The taste, colour and texture of the food Will however, deteriorate, so recommended storage times refer to the length of the food can be stored without any change in its eating quality. The flavour of foods with a high fat content tends to deteriorate more quickly than that of other foods. Since people’s opinion about the flavour of food vary. Opinion about storage time will also vary. As a guide, the following table gives some ties for foods stored in a four star freezer:

Food Storage Time (Months)
Beef 12
Lamb and veal 9
Pork 6
Mince, offal, sausages 3
Pate 1
Chicken and turkey 12
Duck and game birds 6
Giblets 3
White Fish 6
Oily fish 3
Shelfish 2
Bread and cakes 6
Fruit 9
Vegetables 12
Ice cream 3

Blast freezers
Commercially prepared frozen food is frozen in a blast freezer. The blast freezer is a chamber with a continuous blast of cold air at -20°C circulating through it. This provides very rapid method of freezing and gives a better quality product than a domestic free some large catering establishment have a blast freezer.

Open-top display freezers
Open top display freezers are not to be used for freezing food; they are only intended for storing it before sale. Storage times may be different from those shown for a dam freezer, so the manufacturer’ recommendations should be observed. Food must never stored above the freezer load line, since the temperature here Will’ be higher than in the main freezer compartment.

Freezer breakdown
If the freezer breaks down or there is’ a power cut, the food should be left inside freezer, the door or lid kept shut and blankets placed over it. If the freezer is tightly pack the food will probably remain frozen for 24 hours or longer. If the food is still partially fro when the freezer is mended, it may be safe to keep it, but only if the surface temperature the food is less than 5°C. Alliteratively, some foods can be cooked and refrozen. If there is doubt about, an environmental health officer should be contacted to advice about the various options.

Storage of food at room temperature

Dry food stores
All foods that do not require refrigerated storage, such as rice, flour, pulse, canned foods, fresh fruit and vegetables, should be stored separately from dry goods.

Storage rooms should be designed so that pests and insects cannot enter them easily an additional precaution, all open food in the store should be covered and placed above fl level on tubular or mesh shelves, so that if any pests do enter the store, they Will’ not have easy access to the food. To prevent insect’s pests from reaching the food by climbing up the wall, shelves and storage racks should not be in contact with the walls. Any spillages should be wiped up immediately.

Stock rotation is very important. If the packets and cans in the store do not have a date mark, some method of marking must be devised to ensure that old stock is used before newer stock.

Rice, flour and pulses
Foods such as these that are not pre-packed should be stored in mobile metal bins with tight-fitting lids.

Fruit and vegetables
Any plastic wrapping on fruit and vegetables should be removed before they are put in the store because it traps condensation, which encourages mould growth. Mould spreads rapidly, so mouldy fruit and vegetables should be thrown away immediately. Fruit and vegetables should be used as soon as possible after delivery.

Canned foods
Food poisoning from canned food is very rare. Change in color, flavor and texture Will’ take place if” the cans are kept for a long time. The shelf life of acid canned food is shorter then neutral food.

After opening the can the contents should be transferred to a glass or plastic bowl and keep under refrigeration.

Blown cans of puffed cans should not be used.

Storage of Food at High Temperature
If prepared food is to be served within short time of preparation, it will be more convenient to store such food in hot case and maintain’ a high temperature. Bain-Marie heated electrically is a good example. It is filled with water which is heated to 70-75*C (above 63*C. foe not allowing micro-organisms to grow) and food be served is kept m’ the container fitted in the machine.

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