BY-PRODUCTS OF THE MEAT-FREEZING INDUSTRY

New Zealand Journal of Agriculture, Volume 81, Issue 3, 15 September 1950, Page 257

BY-PRODUCTS OF THE MEAT-FREEZING INDUSTRY

THE value of by-products of the meat industry to the industry itself and to the country as a whole is too often little realised. Wool, pelts, and tallow have become so important to the economy of New Zealand that today they are being looked upon as independent products, whereas their production relies on the ability of freezing works to handle and process all edible and inedible offals into saleable products. This is the first of two articles by I. B. Chisholm which cover generally the handling and processing of the various by-products in the average New Zealand freezing works, and in some cases touch on products processed and packed in the larger and more up-to-date works, so that the extent of the industry may be fully realised. The second article will appear in the next issue of the “Journal.” STRICTLY, by-products of meat include all portions of the animal excluding carcass meat itself. With such a definition of by-products must be included manufactured meats such as smallgoods and canned meat, and although these are not covered in this article, they provide important outlets for various types of edible meats. Some plants extend their operations to killing poultry and handling certain dairy products and would, were it possible, preserve fruit and vegetables in various forms. The facilities required for processing and distributing these products are

almost the same as those in freezing works and the inclusion of these products among those handled results in better utilisation of packers’ facilities and subsequently reduces the margin of costs between producer and consumer. The smaller by-products, namely edible meats and pharmaceutical products, have been saved and packed in some New Zealand freezing works for some years, but greater attention has been paid to this aspect of the industry in recent years, with the result that today there is very little of the live animal which is not utilised to the greatest extent. There are, however, many products which it is not economically practicable to save and process in New Zealand to the same extent as is done by large overseas companies, mainly because of this country’s comparatively small production and limited distributing facilities. In spite of these limitations the industry in New Zealand has vast ramifications and a great volume of labour is required to handle the by-products of about 19,500,000 sheep, lambs, cattle, calves, and pigs which are killed every year, a large percentage of them being killed during the peak few months of the season. Every department m the works handling by-products is connected directly and indirectly with beef-, mutton-, and pig-killing floors from which run chutes and conveyers carrying all the offals as quickly as possible to their respective departments where processing begins. HIDES AND SKINS Historically, hides and skins were the first by-products of meat packing, and apart from the carcass itself, are still the most valuable. This emphasises the importance of proper care and handling of stock on the farm and of hides and skins in freezing works. On farms and elsewhere

before animals reach the works barbed wire, thorns, and parasites may damage hides and skins. In addition fire branding and some other forms of branding and the use of corrosive branding products at sales . and on farms cause great damage to and depreciation of hides. Excessive use of raddle and sometimes the use of tar ■or other unsuitable branding material will depreciate the value of wool. Scores and cuts made in the works have serious . effects on the ultimate use of the finished leather. Leather in large pieces and free from damage procures the highest prices, but poor supervision on the killing floor may ■easily cost the industry many thousands of pounds. The following important points should be borne in mind by anyone who “kills” or who has to remove a .-skin from a carcass:— 1. Completely rested animals are easier to flay and dress than those that are heated.

2. Damage may be . caused to the grain of cattle hides by dragging carcasses over hard ground or concrete. 3. The hide or skin should be correctly opened up to leave it as square as possible. 4. Butchers should be completely trained and supervised in the flaying of hides or skins if reduction in the percentage of scores and cuts is to be achieved. In the works all cattle hides and sheep, lamb, and calf skins are handled and . processed to some extent. The skins of pigs are normally left on the carcass and only the hair is removed. Goat skins are usually sold direct to trading companies for tanning for fancy goods. Cattle Hides When a cattle hide is removed from the carcass it is conveyed to the hide room, where it is thrown over a low, convex table. Here the hide is

fleshed or flayed by hand to remove any surplus fat and meat left on in butchering, particularly on the neck and butt end. These fleshings are sent to the tallow department and any hide trimmings are salted to be processed later into glue. Fleshing, like butchering, should be done only by experienced men.

The hide is then thoroughly washed and scrubbed to remove dirt and blood and hung flesh side up over a wooden horse to drain and to allow the hide to expel the animal heat completely. Salting

After draining, the hide is placed on a stack and the flesh side, which is uppermost, is lightly covered with clean, medium coarse salt, particular care being taken to cover the edges and shanks well. The hide should be left in the stack at least 14 days, but the period will vary considerably according to floor space available and conditions at the plant. . After the required period the salt is swept off and the hides are graded by weight under the headings of bull, ox, cow, and heifer and freedom from fault. The graded hides are neatly folded up and placed in their respective bins to await sale by tender. The hides when tanned are made into sole and upper leather for footwear, whips, straps, bags, athletic equipment, automobile upholstering, etc. Calf Skins Calf skins are handled in the same manner as cattle hides. Most of the finished leather is used in the manufacture of footwear. Sheep Skins Sheep skins are usually delivered to the washing dollies (wooden or concrete tubs with horizontal four-armed paddles) by water chutes from the killing floor. When the dolly is full of skins the paddle is set revolving slowly so that although the skins are washed, no damage is done to the pelt. About 10 minutes' washing removes all the blood, sand, dirt, etc. After their removal from the dollies excess water is removed from the skins in a hydro-extractor or by wringers. The hydro-extractor consists of a fairly large perforated basket which revolves at 900 to 1000 r.p.m. until the skins are partly dry. Alternatively the skins may be wrung out by passing them flat between the rubber rollers of wringers. If the skins are too dry, wind blast may occur in the pelt; if they are too wet, the sodium sulphide in the paint which is later applied in the depilatory process is diluted and its action on the skin in loosening the wool is retarded. Thus the moisture content of the skin is very important to nearly all succeeding operations. Painting There are three methods for removing wool from the —sweating, liming, and depilatory processes. The last-named is used almost universally in New Zealand freezing works. In the depilatory process a mixture which consists in most works of sodium sulphide and hydrated lime is painted on the skin. The most common way to reduce the solid, concentrated sodium sulphide (Na.,S) to liquid form is to place it in

a tank where it is covered with water and boiled by steam until all the sodium is dissolved. Sufficient water must be added to the concentrated NaS to ensure that after dissolving and cooling it will not revert to its original solid form. After it has been cooled the sodium is run into small tanks where it is broken down to the required strengths by the addition of more water. The strength of the sodium solution may be increased by the addition of stronger NaS but not by evaporation of the water in it. A hydrometer is used to measure this strength at 60 degrees F. The liquid sodium is then run into tanks equipped with slowly revolving paddles and hydrated lime is added until the sodium becomes a paste of the required density. The density may vary slightly according to the grade of lime and its ability to bind with the Na 2 S to make a suitable paste. The paint is conveyed by various means into troughs at the paint table. • On sheep and lamb skins different strengths of sodium are used, and these strengths are further governed by the length of wool on the skin, which varies considerably during the season. The longer the wool, the weaker the sodium sulphide required to loosen the wool from the pelt, and vice versa. The skins are placed on the paint table with the wool side down. The shank, head, and ear skin pieces are cut off and as they accumulate are sent to the pie wool department at intervals. As the skins move along the paint table the sodium and lime mixture is painted on by hand, care being taken not to touch the wool on the edges. At the end of the table the skins are folded lengthwise, with paint to paint and hung up over sticks or placed flat paint to paint, in stacks on trays on the floor. Pulling Within 24 hours the wool is easily removed from the skin. Usually the skins are taken to the pulling board on trays or trucks, but a system of slow-moving

. . . MEAT BY-PRODUCTS: HIDES AND SKINS

chains which take the skins from the paint table to the pulling board is now being gradually introduced. This is a great improvement on older methods, as the 'only labour it requires is that of placing the skins on the chain and removing them at the other end. The skin is opened up and thrown over a convex board fixed at approximately 45 degrees. With a sweeping motion of the hands the wool is pulled off, classed, and the classes thrown into their respective bins. (The further treatment of the wool is described later.) The pelts are then delivered to the pelt department. Pelts Depilating The “green pelts? as they are known at this stage are placed in wooden or concrete dollies. The little sodium solution still on the pelts is sufficient to dissolve any wool which may still be adhering to edges and necks. Lime in the dollies penetrates the pelts through the epidermis, breaking up the proteins and swelling the pelts to give them a plump appearance. The old method of placing the green pelts in stacks to lime is being superseded by this 24-hour dolly process. After processing, the pelts are transferred to the bating dollies. Deliming and Bating The pelts are washed in dollies in soft cold water for a short period to remove any sodium and lime still adhering to them. The temperature of the water is then raised to 90 to 100 degrees F. and the bating material added. The action of the bating material is to remove the lime, causing the plumpness to disappear, and the pelts become soft and flaccid by the action of the enzyme trypsin in the bate. The paddle in the dolly is revolved slowly for approximately 2 hours during the bating process, after which the pelts are washed again in clean water.

Pickling After a brief period of draining, the pelts are placed in dollies which contain a solution of sulphuric acid and salt in fixed quantities. The pelts immediately absorb the pickle, and further salt and acid is added during the process until the original chemical content of the pickle remains constant. This means that the pelts are saturated and thus are cured. During this process the pelts are continuously agitated by a slowly revolving paddle. A chemical test is usually taken on each dolly of pelts to verify complete curing, which takes about 2 hours. After curing, surplus moisture is drained from the pelts. Fleshing Fleshing is carried out mechanically. The pelt is hung over a rubbersurfaced roller and the flesh side is brought into firm . contact with a rapidly rotating, right- and left-hand spiral knife cylinder. This revolves at not less than 1500 r.p.m. At the same time the rubber roller rotates slowly and delivers the skin back to the operator. (There are other types of fleshing machines, some requiring two operators to each machine.) The pelt is then delivered to the grading tables. Grading Pelts are graded according to which of the following three principal headings they come under: — 1. Free from all defects such’ as cockle, pinhole, machine breaks, prominent Corriedale rib, scores, high grain, broken grain, disease, etc. The pelt can be damaged to the extent of being graded down by pulling the animal round the yards by the wool and by general faulty handling in the works. 2. Area in square feet per dozen pelts. 3. Thickness of the pelt. From these headings approximately 12 grades for sheep and lambs are commonly used.

MEAT BY-PRODUCTS -. =• . < 'PELTS ' f

Packing

On the grading tables the pelts are rolled up into bundles of 6 in their respective. grades and placed in bins . until a sufficient quantity is on hand to pack into casks. During . packing, medium coarse salt is lightly sprinkled around the bundles of pelts. Approximately 20 dozen sheep pelts or 42 dozen lamb pelts may be packed in a standard size cask. Alternative Handling Procedures There are several other methods of handling the pelts through the various processes, but that described is probably most commonly adopted. The pros and cons of each method are too detailed to go into, but they all centre around the stage of the processing at which the pelts are best fleshed. Some works flesh after depilating and before bating; others flesh between bating and pickling. WOOL AND HAIR Wool In a freezing works as many as 70 grades may be used for slipe, washed, and scoured wools, and the method of classing is fundamentally the same as that of greasy wools. Certain points governing classification which are essential whether the classing is of greasy or slipe wools include: 1. The fineness of wool, 2. The strength of the fibre, 3. The length of the staple, 4. The softness or hardness (feel) of the wool, 5. Colour, and 6. Freedom from foreign matter. Simply, the slipe and washed wools may be graded into quarter-, half-, three-quarter, crossbred, Leicester, and Lincoln types, to which apply superfine, firsts, seconds, .and washed thirds for quality; pelt, .cloth, and comb for length; brands and light and heavy seed for condition. These grades are very elastic so that the packer may sort his wools to the best advantage. Each class of wool is delivered in bulk to the mechanical wool driers, where it is thoroughly dried by hot air, a process which requires up to 20 minutes, according to the type of drier. The wool is then delivered to the wool room, where it is placed in bins to cool before baling. Bales, which must not weigh more than 4001 b., are pressed by hand or mechanical means, branded, and stored •to await sale and shipping instructions. Pie Wool All the head, ear, cod, shank, and pullers’ skin pieces which are too small to paint by the depilatory process are taken to the pie house, where under •normal atmospheric conditions they are left to sweat in heaps about 9 to 12in. high. When the wool is easily pulled from the skin it is picked off the head, ear, and cod pieces by hand. Some works put the pieces in vats with hot water to quicken the bacterial action which loosens the wool root. The skin on the shank and pullers’ pieces are left to decay away from the wool, which takes on a brown colour from the chemicals in the decayed skin. The wool is scoured in hot water to remove the fat which it absorbs. All the pie wools in their respective grades are •then washed in cold water, wrung out, dried, and baled. Hair The body hair of cattle is removed iby the tanners and put through a pro-

MEAT BY-PRODUCTS: PELTS, WOOL, AND HAIR

cess of washing and drying to be used for felting or as a plaster retardent. Cattle Tail Hair Cattle tail hair, often known as curled hair, is largely used in upholstering motor-cars, in which comfort is all important. The curled hair possesses several advantages: 1. It is permanently resilient, 2. It is permanently soft, 3. It is nonabsorbent, and 4. It is non-heating. The hair may be clipped from the lower half of the tail, where it is over 4 to sin. long, or, after scalding in water at 160 degrees F. for a few minutes, the long hair may be easily pulled - out, washed, and placed on wire-netting racks in the open air to dry. When ready, the tail hair is baled up and sent to manufacturers, . who process it into curled or fluffed hair. The long hair is often sold to mattress makers. Ear Hair ’ Ear hair is not usually saved in New Zealand, but is saved to some extent in other countries. The delicate hairs inside the cow’s ear are manufactured into artists’ brushes. Hog Hair Most of the hog hair produced in New Zealand is destroyed at the works, because there is not a ready outlet for the processing of this product. Its uses are innumerable, but it mainly provides stuffing for upholstered furniture. PHARMACEUTICALS The science of glands and organs in both humans and animals is a highly technical one. A brief description of the action and work of some of these glands in the body is necessary to an understanding of their use and benefit to medicine as a pharmaceutical product. The majority of the glands saved are classed as ductless or endocrine glands,. which are scattered through various parts of the body. Products of these

glands are known as internal secretions. Each of the ductless glands secretes a substance which exercises a particular effect upon the functions of the body and governs in some measure the orderliness of human and animal life and the conduct and character jof the individual. Conditions such : as cretinism, excessive or retarded growth, abnormal features, extreme nervousness, and idiocy can frequently be attributed to derangements of these glands. Should any gland fail to secrete its substance into the bloodstream, it is usually possible to make up the deficiency by feeding or injecting extracts of that particular gland into the body. The active principles of the ductless gland secretions have been isolated in most cases and are known as hormones. These are very powerful in their action; even in microscopic quantities they produce effects, but. the administration of these extracts in medicine is quite complicated. There are many other glands not strictly endocrinal used in the preparation of pharmaceuticals and in several cases more than one product is prepared from a gland. The frozen glands and organs as they are received from the works are prepared in the United Kingdom, Australia, U.S.A., and other countries under close supervision in laboratories especially set up to process them into pharmaceutical products. Large quantities of glands are required to produce lib. of the finished product; for example, approximately 38 fresh beef suprarenal glands weigh 11b. and about 25,000 glands or 12,500 cattle are required to prepare lib. of the dried finished product. To produce lib. of dried corpus luteum about 1500 ovaries are used. The value of such drugs may well be imagined. In New Zealand nearly all the glands and organs saved are from cattle and bobby calves. Their location and collection

from the other meat-producing animals require some skill if they are to be efficiently carried out. Endocrine Glands Thyroid The thyroid gland, which is situated on either side of the windpipe (trachea), consists of two maroon lobes connected by an isthmus of tissue. It has a controlling effect on the body heat, energy rate, growth and. size of bones, intelligence, and in general the speed of living. If this gland enlarges in humans, it is called a goitre. The substance the thyroid secretes is thyroxin, deficiency of which will bring on certain lymphatic swellings and dwarfishness in certain cases. Too much secretion may cause digestive troubles, insomnia, and loss of weight, making the thyroid perhaps the most variable organ in the body. Parathyroid The parathyroid glands, which are near the thyroids, are four in number and about the size of a wheat seed. Their main work is to regulate the amount of lime in the blood and cells and the rate of coagulation of the blood. Their removal from the live animal would result in nervous spasms and eventually death. The extract of the gland is used in the treatment of tetanus, but is rarely saved in this country. Thymus The thymus gland is described in edible meat by-products as the sweetbread. Its pharmaceutical product is used in the treatment of rickets. Pituitary Found in the base of the brain, the pituitary gland consists of two lobes known as the anterior and posterior lobes. Each has a different function; the former is responsible for growth and is associated with sex glands; the latter has the ability to stimulate involuntary muscles, thus being valuable in obstetrical cases.

. . . MEAT BY-PRODUCTS: GLANDS AND ORGANS

Pineal • The pineal gland is a cone-shaped tissue about the size of a pea hidden in a small cavity of the brain. Among other functions it regulates childhood growth. The pineal and pituitary glands are usually removed when the head is split open to extract the brain. Suprarenal Situated close to the kidneys, the two suprarenal glands are easily recognised by their yellowish fatty colour. The outer portion of the gland (cortex) is associated with general debility and emaciation and the inner portion (medulla) secretes a substance called adrenalin which may constrict the capillaries and temporarily raise the blood pressure. It is sometimes called the gland of combat because it quickens its secretions to control the nervous and muscular system at moments of pain, fear, and rage. Sex Glands The primary function of the ovaries and testes is to form reproductive cells for external secretion. They also secrete substances internally which control secondary sexual characteristics. This is shown by the castration of a ram lamb; the wether never develops the characteristics of heavy conformation and muscle of the entire ram. The various extracts from these glands have been used in ovarian disturbances and it is possible with their use to induce lactation without pregnancy. Other Glands and Organs Pancreas The pancreas is the most common of the glands saved, possibly because it is the most easily found in cattle, sheep, and pigs. The gland is situated within the abdomen. The substance it secretes internally regulates, among other things, the process of metabolism

and the supply of sugar for the main organs of the body. Its pharmaceutical product is insulin, which is important for combating diabetes. Pancreas glands saved from bobby calves provide the best source of insulin and supply a potent product which is invaluable in the worst cases of diabetes because a small injection of it is equal to several injections of the standard product. made from cattle glands. Livers All beef livers which have been rejected for. edible purposes but are not badly diseased may be processed to derive a liver extract. The extract is used in cases of pernicious anaemia. Gall The gall bladders are carefully removed from the livers of cattle, sheep, and lambs, and are cut open over a sieve through which the gall or bile runs into a steam- or water-jacketed pan. It is then heated to 180 degrees F., which is maintained until the moisture content is reduced to 25 per cent., when it is run into casks to cool. Its extract, which is in the form of bile salts, is used in the manufacture of various medicinal preparations, and its value is estimated for this purpose on its cholic acid content. A common use of gall is in the manufacture of inks and dyes. CASINGS The casings of pigs, sheep, lambs, and cattle have long been valuable byproducts of the industry, especially in the form of containers used by sausage manufacturers. In later years their value as various types of strings and surgical ligatures became apparent, thus establishing a firm secondary industry. In New Zealand for many

years the buying and selling of casings have been monopolised by certain overseas firms and many freezing companies have been obliged to sell their casings to such firms on the killing floor. Competitive overseas prices in recent years have changed this position and many freezing companies are taking over the handling and processing of their own casings. A few of the larger works have been packing graded salted casings for some time, and, apart from local requirements, the bulk of the production has been exported to England, Canada, or U.S.A. The casings are derived from various parts of the internal organs, some of which are enmeshed in the ruffle or crown fat, the function of which is to keep the organs in place in the live animal. The small intestine is saved from all meat-producing animals; only parts or some of the other casings, such as oesophagus, large intestine, stomach, and bladder are collected. Small Intestine The small intestine of the mature ox is approximately 100 to 120 ft. long; in the sheep it is up to 90ft. and in pigs up to 50ft. The intestines are pulled or cut free from the ruffle fat without breaking or scoring them and in such a way as to leave the fat in its entirety as much as possible. After the intestines have been pulled and cooled in cold water they are stripped free of their contents by being run through the operator’s fingers and then stripped again either by hand or machine. The intestines are cut into graded lengths and tied up in sets of 10. These are immersed in water about 50 degrees F. until the mucus on the muscular tissue is fermented or softened. This process may be shortened by using warm . water, but over-fermentation will weaken the casing. Intestines may be fermented in brine solution; this has the advantage of eliminating the objectionable odour of the department. The intestines pass through a cleaning machine to remove the mucus, and thorough cleaning usually involves

MEAT BY-PRODUCTS: CASINGS

running the intestines through the machine a second time, after which they are termed casings. The casings are placed in chilled salt solution until they are delivered to the tables. On the grading tables the casings are expanded by water and graded by width or diameter. The casings may be divided into narrow, narrow medium, medium, and wide grades, a classification which is known as calibrating. Considerable extensions of these grades are made by the packers in measuring for length and calibre, as they must pack their products as competitive markets demand. After grading, the casings are salted down and packed into casks. Careful handling and close supervision right through the processing are necessary to produce the greatest yield and at the same time preserve the most attractive colour. Sheep and lamb intestines have several uses apart from sausage containers. Strings for nearly all types of musical instruments have been made from them for many years and before the Second World War there was

much competition for them between U.S.A, and European countries. Tennis strings are an important product to . this sporting country and a large percentage of New Zealand’s requirements are made locally. It is said that the intestines from 11 lambs are used to produce sufficient strings for the racquet of a tennis player. Intestines also have a medical value in the form of surgical ligatures. They are graded by hardness, as the surgeon uses that particular grade of ligature that will dissolve in the wound at the end of the desired period. The silky threads used by the surgeon are taken up or absorbed by the flesh of the patient. Oesophagus Better known as the gullet or weasand, the oesophagus, which is about 2 to 3ft. long, is the inside casing and is saved only from cattle. It is usually used as a container for cooked sausage meats. Large Intestine In cattle the large intestine may be divided into three parts. The caecum or bung is about 4 to sin. in diameter; the colon is part of the intestine which carries on from the bung and slowly diminishes to 2in. in diameter; the rectum or wide middle is relatively short. All these, the last two to a less extent, are used in various forms as sausage containers. The colon or chitterling from the pig is saved as an edible product. Stomachs Apart from its use as tripe, the pig stomach is cleaned and used as a container, or processed further to yield the digestive ferment pepsin from the stomach lining. Bladders Cattle and pig bladders are inflated with air, trimmed, and dried to be used as containers for various materials. (To be continued.)