12 Storage Requirement in Food Industry

V. Suganthi

1. INTRODUCTION

All catering establishments, irrespective of the volume of food handled, should have adequate, temperature controlled storage facilities to protect food from any kind of spoilage. Temperature controlled storage facilities include a dry food store, refrigerated stores and deep freezers. Storage space required depends on quantity purchased.

2. OBJECTIVES

At the end of this chapter, you will be able to:

Know about the different types of storage in a food service institution.
Have adequate knowledge about the guidelines about proper storage.
Know about the ways of maintaining sanitation, safety and security in stores.

3. GENERAL GUIDELINES FOR STORAGE

Wash items that need washing and prepare food for storage.
Wipe cans.
Rotate food supplies using the ‘first-in, first-out’ basis (FIFO) method. Goods should be placed in the order received. Date goods on receipt and place new deliveries in the rear of the store. The ‘Best before’ or ‘Use by’ date should be marked on the product.
Store foods in areas designed for storage only and not in the kitchen and larder. Each storage area should be separate.
Keep all goods in clean wrappers or containers. Dirty wrappers attract pests and contaminate food. Use waterproof and airtight material. Check packets before storing them.
Keep storage areas clean and maintain a regular cleaning schedule.
Keep vehicles used for transporting food within the establishment clean.
Access to the food stores should be restricted to prevent pilferage and to control stocks.
Periodic inspection and turnover of foods is necessary to check their condition.
Maintain appropriate temperature depending on the type of storage.
Avoid overcrowding of stored food and overstocking. Adequate air circulation and ventilation is necessary.
Food should be used as soon as possible because even under ideal conditions of storage there is loss in nutritive value, flavor and freshness.
Goods are stored as soon as they are purchased. Potentially hazardous food items should not be left in the open yard or receiving area. They should be refrigerated or frozen immediately.
Separate areas should be made available for storage of equipment, cleaning materials, empty cartons and packaging materials.

4. DRY STORAGE

The dry food store should be airy, well lit, clean, protected from pests and excessive moisture. All foods that do not spoil at room temperature are stored here, for example, whole cereal grains, pulses, flour, sugar, oil, canned foods, etc. The temperature in the store ranges from 15-21 degrees centigrade (15 to 70 degrees F) and a relative humidity of 50 to 60 percent.

Features of a dry store

The floors and walls should be made of materials which are easy to clean.
The walls should be tiled or enamel painted.
Cracks and crevices in the walls and the floor should be closed to prevent dust from accumulating and pests from hiding.
Cupboards and racks for storing containers should be of simple design.
Shelves should be adjustable and removable.
Shelves should be slatted to improve air circulation and should be made of non-corrosive material.
Shelves should be placed 5 cms away from walls and 15 cms away from the floor level. This helps in eliminating hiding places for insects, protecting food from dampness, keeping food containers clean and in routine cleaning of the stores.
Doors should be self closing and windows should have frosted glass to keep out light which would otherwise change the colour of the spices and turn fat and oil rancid.
The containers used for storage should be in good condition. They should be easy to clean, impervious and made of non-corrosive and rust-proof material. If galvanized or enameled, they should not be chipped.
Each container should have a metal scoop in it. Lids should be tight fitting, moisture proof, preferably hinged and self closing.
All stocks should be inspected once a week.
Damaged goods should be discarded at once to prevent further spread of damage.

5. REFRIGERATED STORAGE

The term ‘refrigerated store’ includes the domestic refrigerator, reach-in refrigerator, the walk-in chiller, the cold room and refrigerated display cabinets. Storage of foods at refrigeration temperatures retards bacterial growth but cannot undo any damage already done.

Perishable foods like raw meat, poultry, fresh fish, stocks, soups, gravies, milk and milk products, cooked cereals can be held for short periods in the refrigerator. The cabinet temperature should not exceed 4 degrees Celsius. Bacteria, yeasts and moulds grow more slowly at refrigerator temperatures as compared to room temperature, so although foods will spoil when they are refrigerated, the rate of deterioration is much slower because generation time is longer.

The maximum storage time in the refrigerator at ideal refrigeration temperature for some perishable foods are:

Shellfish- 1 day
Raw fish- 2 days
Minced meat- 1-3 days
Cooked fish- 3 days
Poultry- 2-3 days
Eggs- 14 days
Meat- 3-5 days
Milk- 3-7 days
Curds- 5-15 days
Paneer-5 days
Cheese- 3-4 weeks
Cream-3 days

The ideal refrigeration temperatures for specific foods are:

Fish- -1 to 1 degrees C
Meat and poultry- 0-2 degrees C
Dairy products- 3-4 degrees C
Fruits and vegetables- 4-7 degrees C.

The temperature of the refrigerator should be checked regularly by placing a thermometer in the war5mest part of the refrigeration unit. If temperatures below 5 degrees C are not maintained, it needs to be checked. The likely reasons for this inadequate cooling could be:

1. Opening the refrigerator very often.

2. Leaving the door open for long.

3. Placing hot foods in the refrigerator.

The refrigerator should be cleaned inside out. Cleaning should coincide with defrosting. The time for cleaning should also coincide with the time when the refrigerator is relatively empty. This makes the task easier and minimizes chances of contamination of food. All shelves and trays should be removed and washed in a warm soda solution, dried and replaced. The floors and walls of the cold room should be mopped and brushed. This cleaning should be done weekly for large refrigerators and fortnightly for smaller ones. To prevent foods stored in it from developing fridge odour.

Operating procedure

The refrigeration unit should be placed in an airy and well ventilated place away from any source of heat.
It should not be overcrowded as this hampers the circulation of cold air.
Milk and milk products should be tightly covered to prevent absorption of odour and should be kept away from foods with a strong odour.
Prepared food should be stored above and not below raw food, to prevent cross-contamination.
Food stored in glass or metal containers should be stored in the lower part of the refrigerator to prevent condensation drippings from affecting other food items.
The refrigerator should be opened for the shortest possible time and the door should not be left open.
Liquids, meat, fish and poultry should be placed in the coldest part of the refrigerator closest to the coils.
Foods to be stored for the longest time should be stored at the coldest temperature.
Foods should be stored in clean covered containers and not in their original pack or can.
Covering food protects it from cross contamination, drying out and from absorbing odours.
Do not use refrigerator to cool foods which are at high temperatures. The escaping steam will not only increase the frost formation on the coils but will increase the temperature inside the refrigerator, thus favouring the growth of dormant microbes.
In walk-in coolers, store foods away from the walls and floor.
Hang meat and poultry on hooks for better air circulation.
Do not refrigerate canned and bottled foods unless specified on the label.
The refrigerator should be defrosted regularly to prevent ice building up on the refrigeration coils. Additional ice on the coils reduces the efficiency on the refrigerator.
Green leafy vegetables and mushrooms should be stored in perforated polythene bags to prevent spoilage by moisture accumulating in the bag. Extra moisture accelerated the growth of microorganisms.
Never use a sharp instrument to remove frost from the coils or frozen foods that is stuck to the coils, as this can damage them. Use a tray of warm water instead.

Chillers

Chillers are necessary in large catering establishments to reduce the temperature of large portions of food to 15 degrees C or lower in a short time of one and a half hours. Once chilled, the food can be promptly refrigerated. The walk-in chilling room contains a refrigeration unit and a fan to circulate cold air.

6. FREEZER STORAGE

The term freezer store includes the commercial deep freezing cabinets, walk-in freezers, open top display freezers, blast freezers and the frozen food storage compartment of the domestic refrigerator. The freezer store is used for preserving food for longer periods than the refrigerator, the temperature being so low that food turns into ice and is maintained in that state. This preserves the colour and flavor of food better than the refrigerator, especially if the food is blast frozen.

Most bacteria can survive the freezing process and remain dormant for many months or years in frozen foods. Only fresh high quality foods should be frozen because freezing cannot improve the quality of contaminated food. When frozen food is thawed and the temperatures reach the danger zone, the dormant bacteria starts multiplying rapidly. Therefore food should be thawed properly before being cooked.

Foods to be stored in the deep freezer should be at room temperature and wrapped in moisture proof material to prevent dehydration and to keep odour and contaminants away. The wrapping should be air tight. All packets should be labeled and dated before being frozen.

The temperature of the deep freezer varies from -6 to -25 degrees C or lower, as in the case of blast freezers. In blast freezers it may be lower than -35 degrees C. The function of some freezers like the frozen storage compartment of the refrigerator is to already frozen foods.

Guidelines for freezer storage

The temperature should be maintained at -18 degrees C to keep the food safe and the thermostat and the thermometer should be checked regularly.
Each time the food is thawed, microbes start growing and the damage cannot be rectified by re-freezing.
When thawed food is refrozen, the process of refreezing is relatively slow and results in the formation of large ice crystals which affects the texture of the food when it is thawed again.
Frozen foods should be well packed to prevent freezer burn, cross contamination and absorption of odour and flavor. Freezer burn is caused due to very low temperatures and results in discolouration and dehydration of the exposed food.
The temperature at which frozen foods are delivered should not exceed -15 degrees C.
The freezer unlike the refrigerator should be tightly packed with frozen food as cold air circulation is uneconomical.
In case of power failure or breakdown of the freezer, the freezer door should not be opened and the food should be left inside. A well stacked freezer can keep food frozen for a day or more.
It is better to cook foods which have thawed and then refreeze them.
Lengthy freezer storage influences the taste, colour and texture of foods and increases the possibility of spoilage and contamination.
The flavor of foods with a high fat content deteriorates faster than other foods.
Frozen foods should be put in the freezer immediately after delivery and only the quantities required should be removed.
The freezer should be adequately insulated, well lit and doors should have proper gaskets.

Blast freezing

This is a method of rapid deep freezing of packed cooked or uncooked foods by a continous blast of cold air in a tunnel or chamber at temperatures as low as -40 degrees Celsius. Because of the very rare method of freezing, the quality of the product i.e., its freshness is preserved. Quick freezing produces very tiny ice crystals in food which do not damage the cells. Once frozen, food should be stored at -20 to -30 degrees Celsius.

7. STORAGE OF SPECIFIC FOODS

Meat and meat products: They should be refrigerated soon after delivery at 0-2 degrees C. This temperature minimizes and controls bacterial growth if meat is contaminated. Raw meat should be wrapped loosely for better air circulation. Cooked meat should be wrapped tightly. Cooked and raw meat should be stored separately.
Poultry: They is more perishable than meat and should be stored at 0-2 degrees C. Whole dressed birds may be loosely wrapped in wax paper or aluminium foil and should be refrigerated for three days. Frozen poultry is stored at a temperature of -18 degrees C and should be cooked soon after thawing. It should be used six months after processing.
Eggs: They should be stored at 4-7 degrees C. Always refrigerate eggs. Eggs stored in the refrigerator can stay fresh for two weeks as against three days at room temperature. They should be stored with larger end up. At 2 degrees C, eggs may be stored for 9-10 months. Treatment with pure, colourless, odourless mineral oil increases shelf life by several months.
Sea foods: These should be stored at 0 degrees C. Fresh fish covered with ice may be stored for three days. If kept at 0 degrees C without ice, then fish should be used within 24 hours.
Dairy products: Fresh milk should be stored in cold room or refrigerator. Milk should be stored at 3-4 degrees C for five to seven days. Milk powder should be stored at 10-21 degrees C and can be stored upto one year if not opened. It should be refrigerated after opening. Butter should be stored at 3-4 degreed C for two weeks.
Vegetables: In general, vegetables should be stored at a temperature of 4-7 degrees C. Onions and potatoes should be stored in ventilated containers in a cool dark place. Potatoes and other vegetables should be stored in sacks if purchased in bulk. As vegetables respire, they require ventilated storage. They should be stored on wire racks adequately above ground level. Cabbage and green leafy vegetables should be used as soon as they are received or else emptied on the racks and refrigerated. They should be checked thoroughly if they are to be held for a day or two.

8. DANGER ZONE

The food handler should always remember that food cannot be stored indefinitely as all foods will ultimately spoil. Bacteria is present everywhere. Even if one is careful and all attempts are made to prevent contamination, some bacteria will still find their way into food and contaminate it. It is therefore necessary to prevent multiplication and contamination at every step of food preparation with the help of appropriate time-temperature control.

Bacteria multiply over a wide range of temperature. The range of 5-63 degrees C (45-145 degrees F) is called the danger zone because the hazard of bacterial growth is great within this range. The golden rule of food protection is called time and temperature principle. It requires that all potentially hazardous food be kept at an internal temperature above 63 degrees C (145 degrees F) during display and service. If, during periods of preparation, potentially hazardous or high risk foods must be exposed to temperatures between 5 to 63 degrees C, this exposure time must be kept to an absolute minimum. The longest period for which food may remain in this zone is four hours, but food should not be in the 15-49 degrees C for longer than two hours.

9. PLANNING STORAGE SPACES

Whatever the type of storage required, its planning and arrangement depend on a number of factors such as proximity to markets, menu and purchasing policy of the establishment with respect to the form in which foods are purchased, whether raw, partly prepared, processed or frozen.

Layout

Every store should aim at reducing mental and physical strain, time and effort of store staff in locating items when required, by placing them correctly on delivery. Depending on the size of the store, a reception platform approximately 90 cms in length at the delivery point helps to prevent excessive lifting.

Whatever the type of arrangement, store items must be placed at heights which allow for easy reach and readability, so that time is not wasted in trying to search for items when required. There should also be sufficient clearance between items, to allow them to be easily reached and replaced.

10. STRUCTURAL FEAUTRES

The ceiling of the store should be atleast 3.5 to 4 metres high with provision for ventilation and lighting all protected by grills for security. Enamel painted walls and ceilings, with floors of concrete or heavy tiles are recommended to withstand wear and tear resulting from the movement of goods on trolleys or carts. Construction of ceilings, floors and walls should be aimed at easy cleaning to maintain hygiene; walls near floors should be damp-proofed to prvent microbial infestation and spoilage of foods.

All fittings in the stores should be of a type which can be easily dismantled for regular cleaning. It is preferable to have racks or shelves of metal or any other non porous material, situated atleast 5 cms away from walls, or placed in the centre of a room with aisles around them, so that each part of every shelf is accessible. The space between the shelves may vary from 50 cms to 90 cms, depending on the size of the containers to be stored. For small cans or jars, 30-40 cms is the usual spacing.

The recommended height for racks is 2.3 metres. Racks higher than this will pose problems in reaching for placing and issuing of items, fixing of lighting, etc. For the storage of jutebags or cartons, slatted platforms with 8 cm clearance from the floor are advisable, for free air circulation through piled goods. A work table is necessary near the entrance of a storeroom for replacing or handling of requisitions and issuing of stores. Provision of scales either fixed on the wall nearby or placed on the table, are important for issuing small quantities.

11. LIGHTING

Flourescent lightings in trough fittings placed in a row at right angles to the shelves are the most suitable because light penetrates best from this angle into each shelf. If the shelves are light coloured, light gets cross reflected for greater advantage. Lights should be fitted high enough above the topmost shelves of the store to prevent damage to fittings while goods are being placed or removed. Lights fitted too close to food items also generate heat which can affect the quality of the stocks.

12. VENTILATION

Windows and exhaust fans provide suitable ventilation for storage, but these should be situated high up on the walls to provide ample and uninterrupted circulation of air, while preventing direct draughts on the foods stored.

13. DIMENSIONS FOR STORAGES

Dimensions for storages should take into account freedom of movement between aisles in a storeroom. Where trolleys or carts are used, the dimensions need to be adjusted to requirements. In no case should passages allow movement of one person at a time. Some dimensions for movement in storerooms are:

Width of gangway-90 cm
Width of aisles
For single person-60 cm
For person carrying a load-65 cm
For two persons-70 cm
For two persons with load-90 cm
For an average handtruck-1.2 m
For two average handtrucks-2 m
Turning space for an average truck-2m

Door openings should be large enough to allow free passage of supplies and equipment.

This is usually three and a half feet (1.07 m) for single and five feet (1.52 m) for double doors.

14. SANITATION, SAFETY AND SECURITY OF STORES Hygiene and sanitation

Hygiene and sanitation in and around the stores is of paramount importance. It is therefore necessary to keep stores neat and clean and to prevent attack of food by bacteria and moulds. Dry food stores should be fly proofed and walls treated with suitable insecticides. All stores should be guarded against rodents and pests, to safeguard both staff and customers against infested and contaminated food. It is good policy to formulate a schedule or chart for regular cleaning and maintenance of stores.

The following points may be kept in mind while preparing a schedule:

Wash floors, walls and shelves once a week or fortnight and disinfection of spaces.
Inspect incoming food for signs of damage, spoilage or infestation before storing.
Arrange food systematically, so that old stocks are used first.
All opened packages should be put in covered airtight containers before re-storing.
Foods of similar types should be stored together.

Staff should be given clean coats, and made to observe proper personal hygiene while handling food items.

Security

Since stores stock items of daily use which are vulnerable to pilferage and theft, it is extremely important to provide proper safety and security measures at the designing stage. In addition, stores have a lot of money blocked in stocks, which make security a vital aspect of store management. The safety hazards to which stores can be exposed are:

Infestation or contamination of food held in storage.
Theft or pilferage.
Microbial spoilage due to improper temperature and humidity controls especially in cold storages.
Fire.

Some important guidelines for maintaining security in stores are:

Have minimum inlets or outlets to the stores. It is preferable to have a few well guarded openings placed high up on the walls for exhaust fans. All windows and other openings should be well guarded with mesh and grills. There should be only one door for entry into and exit from stores.
The storekeeper’s office must be positioned such that supervision is possible at all times and the door is in full view during working hours. At no time the store should be left unmanned.
Issue counters must close by roll-down shutters or half doors.
Safety locks must be fixed and the keys to the stores should always be kept in a safe under the charge of a single responsible person. Safety devices such as automatic locks, number locks, and built-in alarm systems against fire, gas leakages and theft should be installed.
A guard on 24 hours duty is important. Well guarded exits inhibit pilferage if a personal checking system is established when staff go off duty.

SUMMARY

Storage of food is an important factor which needs to be considered if the emphasis is on serving high quality products. Depending on the nature of the food, it may be stored in the deep freezer, refrigerator, dry food store or it may be held at high temperatures during the service period. Food stores should be kept scrupulously clean and food should not remain in the danger zone for more than four hours.

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Web links

Books

Roday.S., Food Hygeine and sanitation, Tata McGraw Hill Education (p) Limited, 2011
Arora, Food service and Catering Management: A.P.H. Publishing Corporation, 2007
Foskett & Paskins: The Theory of hospitality and Catering, Hodder Education, 2016
Sethi, Institutional Management: New Age International publishers, 2004
West & Wood, Food Service in Institutions, Wiley Eastern Limited, 2000