9 Purchasing Specification for Perishable Foods

V. Suganthi

1. DEFINITION

Perishable foods are those which cannot be kept for more than two days at room temperature, because certain enzymes present in them bring about physical and chemical changes which are undesirable. Standard purchasing specifications are documents that are drawn up for every commodity describing exactly what is needed for the establishment.

2. OBJECTIVES

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

· Identify and select different types of perishable foods available and used by food service institutions.
· Formulate specifications foe different types of perishable foods used in food service institutions.

3. STANDARS PURCHASING SPECIFICATION

All standard purchasing specifications for food products should include the following information:

Name of product (trade or brand) or standard
Whether conforming to established standards like FPO
Size of container (e.g., weight, can, size)
Count per container or approximate number per kilogram (number of pieces per container if applicable)
Unit on which price will be based

Information that would describe a product in more detail might include:

Product use (e.g., for soups or salads)
Product test procedures used by the food service operationto determine quality compliance if applicable (e.g., degree of ripeness, flavor characteristics)
Quality tolerance limits (for example, number of substandard products in a container of produce)
Weight tolerance limits (range of acceptable weight, such as for meat, poultry or seafoods)

Any other information that helps to describe the condition of the product should be included, as in the following:

Canned goods: Type or style, pack, syrup density, size, specific gravity
Meat and Meat products: Age, exact cutting instructions, weight tolerance limit, composition, condition upon receipt of product, fat content, cut of meat to be used, market class
Fresh fruits and vegetables: Variety, weight, degree of ripeness or maturity, quality tolerance limit, geographical origin
Frozen foods: Temperature during delivery and upon receipt, variety, sugar ratio
Dairy products: Temperature during delivery and upon receipt, milk fat content, milk solids, bacteria content

Buyers can now write definite specifications by citing a known standard, which in itself is a rigorous specification. These reference standards constitute a common technical language for buyers and suppliers.

4. MEAT AND MEAT PRODUCTS

The term meat is generally applied to flesh of lamb, mutton, beef and pork. The commonly used meat in India is lamb mutton, about seventy percent of all meat used comes from sheep and goat. The wholesale cuts of lamb are legs, loin, racks, breasts and shoulders. Each of the wholesale cut is further cut into retail cuts such as chops, roasts and neck slices. Meat sold in the market must be wholesome and fit for human consumption.

The different classes of meat and related products are:

Veal: It is the meat from cattle slaughtered 3-4 weeks after birth
Beef: Meat of cattle over 1 year old
Lamb: carcasses of young sheep which is between 12-20 months old
Mutton: Flesh of animals over 20 months of age at the time of slaughter
Pork: It is the meat of swine
Organ meats: Liver, kidney, heart, pancreas and brain

The tenderness of the meat depends on the age and feeding of the animal. The flavor of meat is determined by various factors such as feeding, age, sex and maturity. The older the flesh, the greater the flavor in most cases; young flesh is not so highly flavoured but sweeter and more tender. Flesh of male animals is stronger in flavor than that of females. Well developed muscles are usually more strongly flavoured e.g., chicken leg as compared with breast.

Flavour of the meat also depends on fat. Pork and mutton for example, have individual flavours depending on the fat. Wherever possible, select meat which is marbled. This is meat where the fat is interspersed between the muscle fibres and connective tissue. This shows good feeding. Marbling helps to keep the meat moist when cooked by dry methods.

Bacon is made by preserving the meat of carefully bred pigs. The preservative used is salt. Good quality well cured bacon should have a pleasant smell, the rind should be thin and smooth, the fat firm and free from any yellow marks, the lean part a good deep pink colour and the flavor mild and mellow.

Selection of meat and meat products

Mutton and lamb

A good quality animal should be compact and evenly fleshed.
The lean flesh should be firm, of a pleasing dull red colour and of a fine texture and grain.
There should be an even distribution of surface fat, which should be hard, brittle and flaky in texture, and of a clear white colour.
In a young animal, the bone is pink and porous, so that when it is cut, only a small amount of blood can be seen. With progressive ageing, the bones become hard, dense, white and inclined to splinter when chopped.

Pork

Lean flesh should be pale pink, firm and of a fine texture.
The fat should be white, firm, smooth and not excessive.
Bones should be small, fine and pinkish.
The skin or rind should be smooth.

Beef

The lean meat should be bright red with small flecks of white fat.
The fat should be firm, brittle in texture, creamy white in colour and odourless. Older animals and dairy breeds have fat which is usually deeper yellow in colour.
Beef in good condition should have streaks of fat running through the lean section and the flesh should rise again quickly after being pressed with fingers. Any cut surface should present a slightly moist appearance to the touch.

5. POULTRY

The term poultry is applied to all domestic birds used as food and includes chicken, duck, geese, turkey and pigeons. Common cuts are chicken and turkey halves and quarters, breasts, drumsticks, thighs and livers. Poultry is classified on the basis of age. The classification of poultry according to Indian standards is:

Broiler or fryer: Chicken of 8 to 10 weeks of age either sex, having tender meat with soft, pliable, smooth textured skin and flexible breastbone cartilage
Rooster: A young chicken, usually 3 to 5 months of age, of either sex, having tender meat, with soft, pliable smooth textured skin and breastbone cartilage that may be somewhat less flexible than that of the broiler or fryer
Stag: A male chicken, usually under 10 months of age with coarse skin. Somewhat toughened and darkened flesh and a considerable hardening of the breast bone cartilage
Stewing chicken or fowl: A mature chicken, usually more than 10 months of age, with meat less tender than that of a roaster and inflexible breast bone tip
Cock: A mature male chicken, usually over 10 months of age, with coarse skin, toughened and darkened meat and hardened breast bone tip

Choosing poultry

Only young birds are suitable for roasting; older birds may be broiled, steamed, braised or stewed. A roasting chicken should be about nine months to a year old; geese and other birds for roasting should not also be older than one year.

Signs of a young bird

The feathers, especially the quills on the wings, should be easy to pull out.
The feathers should be down all over the body, more under the wings.
No long hair on the body.
The skin should be white or clear and smooth.
The feet should be supple, with smooth, even, over lapping scales.
The comb sand wattle should be small and not well developed

Signs which show that a bird is fresh

Feathers – light and fluffy
Eyes – prominent and clear
Smell – not unpleasant
Feet – moist and not stiff and dry
Skin – clear with no dark or greenish tinge

Points which denotes good condition in ducks

The breast should be plump.
The bill and feet are yellow in young birds, but they darken with age.
The webbing of the feet should be smooth, tender and easily broken.
The under bill should be soft and pliable.

6. FISH AND OTHER SEA FOODS

Fishes are classified into fin fish and shell fish. Fin fish are vertebtares and have skin and scales which cover the body. They are sub divided into:

1. White fish which are mainly flat fish and contain oil only in the liver. Most of these are deep sea fish. Examples are pomfret and sole.

2. Oily fish which are mainly round fish and contain fat all over the body. The amount of fat varies from 1.5 percent to 20 percent. These fishes are often pigmantes and tend to be surface fish. Examples are mackerels and sardines.

Shell fih as the name denotes, have a shell covering the body. They are invertebrates. They are sub divided into:

1.Mollluscs: e.g., oysters, scallops, mussels, clams and cockles. They have two distinctly separate shells joined by a hinge-like membrane. The movements are controlled by strong muscle. When the muscle relaxes, the two halves of the shell fall open.

2.Crustaceans: e.g., lobsters, crabs, prawns and shrimps. They have crust like shell. The shells of the crustaceans do not grow with the fish. They are shed every year. With the new one forming to suit their new size.

Fish that are fresh can be easily identified by noting the following qualities:

The skin should be bright, moist and shiny.
The scales should be firmly attached to the skin and plentiful.
The eyes of fresh fish will be convex, the pupil black and the cornea translucent. The eyes should be bright, clear and bulging, and not sunken.
The gills of the freshly caught fish are bright red.
The tail should be stiff.
If fish is split along the backbone and lifted, the bone should stick firmly to the flesh. If the bone separates easily, the fish is stale.
The surface should be free of dirt and slime.
The flesh should be firm to touch with no traces of browning or drying around the edges.
It should not have any off odour.

Choosing shell fish:

They should be bought in season as far as possible. They should be medium sized and of good weight. It is best to buy them alive, particularly oysters, crabs and lobsters. If they are dead, the following precautions must be taken:

The claws of crabs must be springy and not hanging down. The eyes should be bright.
The tail of lobsters should spring back when stretched out.
Shrimps and prawns must be crisp.
Oyster shells must be tightly closed.

7. EGGS

Although eggs of all birds may be eaten, the egg of chicken is used more often than any other. Fresh eggs have best quality. Quality of eggs can be determined by:

Size: The normal weight of an egg in India is between 40-60 grams. The weight depends on the inheritance, stage of laying, season of laying, age, diet and health of the bird. Size does not reflect the quality. Usually, small eggs contain a higher proportion of yolk than large eggs.
Shell: The factors to be considered are its strength, porosity and cleanliness. Any dirt on the shell means the presence of a large number of contaminating microorganisms. Weak shells, rough handling results in damage to the shell. Good egg should be unbroken.
Air cell: As the quality of the egg decreases, the size of the air cell increases due to loss of moisture through the cell especially in warm, dry atmosphere.
Egg white: A fresh egg white broken onto a plate stands up in rounded form due to the viscosity of the thick portion of the egg white that surrounds the yolk. As egg deteriorates, the percentage of the thin white increases.
Egg yolk: In deteriorated egg, the yolk also takes up water from the white,and the yolk membrane i.e., vitelline membrane stretches and when broken onto a plate the deteriorated egg flattens and tends to spread over the plate. If stretched excessively by movement of water into the yolk, the yolk membrane is weakened and may break when the egg is removed from the shell. Separation of white from the white is thus difficult or impossible.
Chalazae: As egg deteriorates, they start to disintegrate and cannot hold the yolk n the centre of the egg.

The quality of egg can be found out by putting it in water. If the egg sinks, it is considered as good. Poor quality eggs float due to increase in size of the air cell and due to loss of moisture. The quality of the egg can also be evaluated by candling. The egg is held against a source of strong light. Candling will reveal:

A crack in the shell
The size of the air cell
The firmness of albumin
The position and mobility of yolk, and
The possible presence of foreign substances like blood spots, developing embryo and moulds

8. MILK AND MILK PRODUCTS

All milk and milk products are highly perishable and are subject to contamination, adulteration and development of off flavours. It is important that the food service manager purchases only the highest quality available. All milk products purchased for food services should come from milk that has been pasteurized and that has been handled in accordance with the best sanitary practices.

9. VEGETABLES

Vegetables are plants or parts of plants that are used as food. All vegetables, particularly green ones, are best when taken straight from the garden. But this is not always possible, so it is essential that one should know how to judge a well grown vegetable. A well grown vegetable is usually tender and free from pests. They are classified into three groups:

1. Green leafy vegetables

2. Roots and tubers

3. Other vegetables

The purchasing criteria for the different groups of vegetables are:

Green leafy vegetables: These should be crisp and give a crunchy sound when squeezed. If the vein of the leaf is broken, it should give a sharp sound. If the leaves are limp, then the vegetables are not fresh.

Roots and tubers: These should be firm and heavy for their size. They should be free from earth and grubs. They should smooth skinned.

Other vegetables: Cabbage and cauliflower should be free from green fly. The cabbage should have a firm heart and the outer leaves should stand the same test for freshness as green leafy vegetables. Cauliflower should have a close white flower. Tomatoes should have rusty red colour and should not be soft. French beans should not be stringy. Peas should be full in the pod and green. Ladies finger should snap if the ends are broken. Brinjals should have a smooth skin and should not be heavy for their size.

The purchasing characteristics of some commonly used vegetables are:

Beans: tender, fresh, crisp, clean, firm, velvety to touch, should break easily with sharp sound
Broccoli: firm bright, tender young stalks, compact bud clusters, dark to purplish green, yellow or wilted leaves indicate ageing
Cabbage: fresh, should be compact, no insect holes, no yellow or withered leaves
Carrot: firm, fresh, smooth, yellow orange in colour, no wilted, soft or flabby portion
Cauliflower: compact, no insects, fine heads, tender green leaves, should not be rough, flowers should not be spread out or yellow
Celery: white or green, medium length, crisp, solid brittle stalks
Brinjal: firm, bright uniform dark rich purple or green colour, free of scars, or decay, should not be wilted, flabby or soft, no insect holes
Ladies finger: young, tender, tips should break easily, should not have any holes
Green peas: young, fresh, tender, bright green velvety appearing pod
Greens: tender, fresh, bright green, leaves should not be holed or withered, leaves should be crisp, stem should be thin
Onions: bright, hard, well shaped
Potatoes: medium size, even shape, smooth, no black or green discolouration
Tomatoes: bright red in colour, firm, no holes, softness, black, over ripened or cracks

10. FRUITS

Fruits are produced from flowers and they are ripened ovary or ovaries of a plant together with adjacent tissues. Fruits are fleshy or pulpy in character often juicy and usually sweet with fragrant, aromatic flavours. Fruits are divided into groups depending upon the shape, cell structure or natural habitat. The different types of fruits are:

Berries: straw berries, gooseberries, blackberries, cranberries
Citrus fruits: sweet lime, orange, lime, lemon, grape fruit
Drupes: apricots, peach. Plums
Grapes: green grapes, black grapes, seedless grapes
Melons: water melon, musk melon
Pomes: apples. pears
Tropical and sub tropical fruits: amla, avocado, banana, dates, guava, jackfruit, mango. Papaya, pine apple, pomegranate, sapota

The purchasing characteristics of some commonly used used fruits in food service institutions are:

o Apple: bright red in colour, firm, distinctive aroma
o Apricots: best if tree ripened, mature, plump. Juicy and be a uniform gold colour o Avocado: fresh and bright appearing with flesh just beginning to be soft when

pressed

Bananas: bright, clean, fresh appearance, dry and not over ripe or under ripe
Citrus fruits: firm but springy to touch, well shaped, heavy for size, thin skinned, juicy, should have few seeds
Grapes: plump, fresh, highly coloured for the variety, firmly attached to stems
Melons: firm, distinctive aroma, no black spots
Pears: fairly firm, free from blemishes, sweet and juicy
Pine apples: fresh clean appearance, almost hollow eyes o

CONCLUSION

The food buyer should have a thourogh knowledge about the purchasing characteristics of different perishable foods to ensure that foods of the highest quality is purchased in a food service institution.

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BIBLIOGRAPHY:

Modern Cookery for teaching and trade, Volume 1 & 2, Sixth editioin, Thangam.E.Philip, Orient Blackman Private Limited, 2010.Arora, Food service and Catering Management: A.P.H. Publishing Corporation, 2007
Food Science, Sixth edition, Srilakshmi.B., New age International publishers, 2015Sethi, Institutional Management: New Age International publishers, 2004
West & Wood, Food Service in Institutions, Wiley Eastern Limited, 2000

WEB LINKS

www.nutrimantra.com/how-good-is-your-egg
www.coursehero.com
www.ssb.sr/smartcons/downloads/poultry%20and %20poultry%20products.pdf
www.hodderplus.co.uk/catering/pc/extra2.pdf
www.best4online.com/food.htm