THE PRODUCTION AND GRADING OF CREAM.

New Zealand Journal of Agriculture, Volume XXXVII, Issue 6, 20 December 1928, Page 378

THE PRODUCTION AND GRADING OF CREAM.

PRACTICE ON FARM AND AT DAIRY FACTORY.

W. Dempster,

Dairy Instructor, Hamilton

Compulsory grading of cream in New Zealand has operated only since November, 1926, and probably no measure for improvement in the quality of our dairy-produce has established a uniform standard so quickly. This is largely due to the method adopted in the examination of applicants for cream-graders’ certificates. The applicant can nearly be said to examine himself. A certain number of cans of varying qualities of cream are graded by the examining officer. The candidate is then asked to grade and classify the same material, after which the cans are changed, and he is asked to regrade them. If he agrees with himself on both rounds, although he may differ to a slight degree from the examining officer, it is a simple matter to teach the true value of flavour. On -the other hand/ if the candidate does not agree with himself on his second trial, it is shown at once that he is not capable of detecting the different flavours, and no amount' of tuition would make him an efficient grader. The majority of graders have taken a keen interest in their work and have done the grading efficiently, realizing that their livelihood depends on the faithful interpretation of the regulations. It is very pleasing, when visiting a cream-grading platform, to see the keenness of the graders, as is shown when their attention is' drawn to a flavour in cream with which they are not familiar. For the assurance of farmers who may think their grade has been lowered without cause, it may be stated that a doubtful cream is rarely lowered without the introduction of a second opinion.

While probably 95 per cent, of our dairy-farmers have accepted cream-grading and realized its advantages, there remain about 5 per cent, of dissentients, who can be divided into two classes. The first class claim that cream cannot be graded ; the others say they know cream and are not getting their correct, grade, the chief cause of complaint very often being that the neighbour is receiving a higher grade. The first class of supplier would stop the industry from progressing, as such a man is loath to attribute to others faculties which he himself does not possess. The senses of sight, smell, and 'taste may be quite defective when applied to cream-grading, much in the same way as

many people lack an ear for music. The man who says he has been among cows all his life and therefore knows milk and cream, really means that he knows milk .and cream according to his own palate. He can invariably distinguish flavours, and thus provides a direct negative to the first class of dissentients. But while he can distinguish flavours he is not capable of giving them their true value, as probably he has not had the opportunity of making comparisons, and therefore does not know the butter-buyer’s requirements. The butter-buyer is the man who must be pleased. The grading of cream, butter, and cheese is done with the object of giving him what suits the market.

The buying of butter is done on the senses of sight, smell, and taste. The grading of cream must also be done by the same senses. It is obvious that it would be a waste of time to apply a scientific test to a sample of cream which did not look, smell, and taste good. No farmer can therefore say that he would get a higher grade for such cream were a scientific test used. It can. be taken for granted that some would get a lower grade, as a scientific test would show defects in cream in the course of development, defects which had not reached the stage where they could be detected by the senses.

GRADING OF CREAM IN RELATION TO THE GRADING OF BUTTER.

Controversy has , sometimes arisen after the publication of dairyfactory balance-sheets to the effect that the percentages of the different grades of cream do not correspond with the different grades of butter at the grading-stores. Where a factory is well equipped and managed and is drawing its supply of cream from one class of country-—either hilly or —and no butter is sold locally,, the whole output being graded for export, it will be found that the grades of cream and butter correspond within a reasonable margin. On the other hand, where a factory is drawing its supply of cream from two classes of country — both flat and hilly— may be a 'wide discrepancy in the percentages of grades of cream taken in relation to the grades of butter. In Auckland Province it is generally noticed that on flat, heavy country rye-grass, cocksfoot, white clover, and (in the north) paspalum are the main constituents of the pasture, and these grasses give a high-quality cream, which if pointed would score 94 points or over. ' But on adjacent hilly or undulating country, which until the advent of general top-dressing gave us our best cream, the pastures have been so changed that trefoil, Lotus major, subterranean clover, and cowgrass are now commonly dominant, and the quality of the cream (more especially in localities where there is much sweet vernal) will be on the border-line between “first” and “finest” grade.

It will readily be seen that the high-quality cream from the flat country when mixed will carry the border-line and a proportion of first-grade creams upwards, and will show a higher percentage of “ finest ” butter. Yet the grading of the cream would be consistent, as were the first-grade cream, manufactured by themselves the result would not be finest butter. Where the greatest proportion of cream is first, and the finest is only on the border-line, the slightest error in manufacture would result in a proportion of the finest being carried downward ; while, had the finest been churned by itself, the resultant butter would have been finest.

During the winter months this is-very apparent, as, while there is a small percentage of finest cream, there is very little finest butter manufactured. As the supply of winter cream .is increasing yearly, there should soon be a surplus of winter butter available for export; and in the writer’s opinion the supply of winter cream to-day is not much inferior to the bulk of the summer supply ten or twelve years ago. As the great majority of farmers have responded in the past few years to the call for improved summer supply, so will they respond in respect to the, winter season. Furthermore, as the winter supply of cream increases there will be more frequent deliveries.

HANDLING CREAM ON THE FARM.

The methods of handling cream at dairy factories in New Zealand compare more than favourably with those of other countries, but our weakness lies in handling milk and cream on the farm. It may be said that only about 15 per cent, of our farmers do everything that is known to be necessary to forward cream in as good a condition as is the milk when received from the cow, and which should result in a cream scoring 94 points or over. At the other end of the scale there may be about 10 per cent, who should not be handling cows at all, as these men, even when shown by a farm dairy instructor that it is possible for them to get a higher grade, soon drift back to their old methods.

There are some 65 per cent, of farmers delivering finest-grade cream around 93 points which can best be described as a borderline cream, while another 10 per cent, deliver a cream between 90 and 92 points. It is from this great bulk, which equals perhaps 75 per cent, of our output, that most of the improvement in the future may be expected. Probably 80 to 90 per cent, of this cream could be improved one point; furthermore, the farmers would be willing to effect such improvement if they only realized that it was possible and necessary. If we are going to hold our high position in the world markets this improvement must be effected. It is often noticeable on a farm from which finest gradeprobably a 93-point —cream is being produced that one or two small things are neglected, and it is these small things which make the difference between a 93- and a 94-point cream or milk. One point in grade may seem insignificant to the individual, but taken on the aggregate of 90 per . cent, of our farmers this one point would place our dairyproduce in an unassailable position. While this article refers primarily to cream, the foregoing paragraphs apply similarly to the production of milk for cheesemaking.

Where actual points for cream-grading have been given, the graders in many instances have awarded only 93 points as the maximum. The spirit of emulation has thus not been encouraged as much as it might have been, and much good could be done were points over 93 awarded to the deserving suppliers. The points awarded in connection with cream-grading are equivalent to the points which the resultant butter would score at the grading-stores if such cream were churned without mixing with other grades. Dairy companies should always send the supplier a docket informing him of the grade, or the grade and the points, awarded to each lot of cream received from him.

FARM DAIRY INSTRUCTION COMBINED WITH CREAM-GRADING.

While engendering the spirit of emulation may lead to appreciable inprovement in the quality of the cream, it is necessary that cream-grading and farm dairy instruction be carried on conjointly. The continuous receipt of low-grade scores, without any assistance or advice toward improvement, tends to a spirit of indifference and hostility. This, in many instances, would be removed by a visit from a farm dairy instructor. When farm dairy instruction was inaugurated and no cream-grading was done the results were disappointing, for until cream-grading was introduced the farmer did not realize the necessity for improvement, and was inclined to look upon the farm dairy instructor as an interloper. Since the introduction of cream-grading, however, the instructor receives a cordial welcome to practically every farm. Dairy-farmers generally recognize the value of . instruction, and have ceased to think that low-grade cream comes' only from farms other than their own. '

Systematic visits are made to the farms by the instructors for the purpose of giving instruction in the best methods of handling milk and cream, the working of milking-machines and separators, the proper and quickest methods of keeping dairy premises and appliances clean, and generally carrying out in a most efficient manner the regular work connected with a dairy. The instruction given in the proper running of a separator almost in itself justified the employment of farm dairy instructors. Such instruction without cream-grading did not give the best results, nor can cream-grading exercise its full benefit without farm dairy instruction. Continual low grading of cream may spur some farmers to better efforts, but others may become disheartened or callous. Service such as the farm dairy instructor can give is helpful to both types.

CHANGES OF FEED AND PASTURES.

Since the inception of cream-grading it has been brought very prominently to the notice of farmers that a change in feed often brings a change in grade, for everything a cow eats must affect the quality of the cream. Even the best of grasses, legumes, or roots if fed exclusively for an extended period, will more or less affect the health of the cow, and in turn affect the quality of the cream. This is very noticeable in the spring, as during the winter months the cows are usually fed liberally on hay, with probably a dearth of roots or green feed. Such cows are more or less in a state of impaction, and when they are turned into paddocks which have been shut up in order to get an early growth, the change from practically a dry feed is so sudden that they commence scouring. Consequently the resultant milk and cream is so strong in flavour that it cannot be classed as finest.

As already indicated, rye-grass, cocksfoot, paspalum, timothy, and white clover produce the best-flavoured cream, the resultant butter being classed as the finest. Cow-grass, subterranean clover, trefoil, Lotus major, and lucerne produce a cream with a distinctive flavour, which cannot be classed as finest, for while the resultant butter may

bring as high a price as finest on special markets it could not be sold as finest on any or every market in the world. Mangolds, kale, chon moellier, rape, soft turnips, swedes, green oats, and barley, if fed in excess, often produce redwater in cows ; and even in herds where the malady is not apparent so many of the cows are affected without showing acute symptoms that the cream is nearly always second grade.

How much this second-grade cream is due to feed, and how much to the health of the cow, is hard to determine. Probably io per cent, of swedes, 12 to 15 per cent, of soft turnips, rape, chou moellier or kale, and 20 per cent, of mangolds could be used as supplementary feed directly after milking without affecting the quality to any marked degree. The writer's attention was recently drawn to some cans of cream which were only passable as second grade. On visiting the farm it was found that the cause of the trouble was that the cows for two days had gorged themselves on partly cured mangolds to such an extent that many of them could not stand up. A cow has been known to eat 60 lb. of soft turnips in thirty minutes. When cows are turned into a turnip paddock twenty to twenty-five minutes is sufficient, as in that time they will get as much roots as is good for them and will dirty less. The important point when changing from winter to spring feeding is to make the change gradually, as much of the first-grade cream would be made finest could the cows in the spring be induced to eat hay after the grass becomes sweet and succulent. A certain amount of success has been achieved along this line by sprinkling the hay with molasses and water.

DEVELOPMENT OF FEED FLAVOURS THROUGH CONTAMINATION.

While it is pretty well recognized that feed flavours as such will not develop in butter, and can be described as characteristic flavours, feed flavours that arise through contamination are a different matter, as they are of bacterial origin and will develop in butter ; consequently a dirty milking-machine can create feed flavour, which, had the milkingmachine and utensils been clean, would not have lowered the grade of the resultant butter. Experiments have isolated the bacterium which causes turnip flavour independently of the purely feed flavour. This organism is also found in the .manure of the cow, even after the manure is dry, and therefore explains what was previously a puzzle, as often a farmer’s cream had turnip flavour at a season of the year when turnips were not available. It is evident that particles of dust containing the bacteria were sucked into the teat-cups when they were being placed in position on the cow’s teats, and, becoming moistened with the milk, set up bacterial action and so developed the turnipflavour. Furthermore; it is pointed out that manure from turnip-fed cows can smell so strongly in humid weather as to taint cream held in close proximity. There are therefore at least these two sources capable of developing turnip flavour when no turnips are being fed.

CLEAN SURROUNDINGS ESSENTIAL.

Many suppliers are going to a great deal of trouble to get finestgrade cream, but because of the lay-out of the shed it is almost impossible to do so, as the air around the shed and separator-room is not pure. Cream when leaving the separator is at just the right temperature to

take a taint, and if the atmosphere is impure the cream is certain to pick up whatever smell there is. . The cream will smell just as does the separator-room or the place where the cream is kept. When in trouble the dairy-farmer might invite some one unaccustomed to milking to pay the dairy a visit. The visitor will probably detect a smell with which daily contact has made the owner familiar. One frequently hears complaints from farmers that their cream was graded low when not sour, sour cream being in their opinion the worst of all. But it is natural for cream to go sour ; non-souring is a sure sign of inferiority. ' It is difficult to get two cans of cream exactly alike in flavour. So well versed do graders become that they can remember flavours as easily as they can remember .the cans. The flavour is just as distinctly impressed on the grader’s mind as if he had seen it.

POINTS IN THE PRODUCTION OF GOOD CREAM

The following points are essential in practice if the farmer is to deliver a good product. If he is neglecting any of these essentials he cannot be said to be doing his best, and has no cause for complaint if his cream is graded other than finest.

(i) Every part of the milking-machine, vacuum-pipes, and tank, separator, &c., must be kept clean.

(2) The releaser-bucket and separator must not be in the engineroom. A passage between the separator and the engine-room is necessary.

(3) Milk should be separated and cream kept in a well-ventilated room, and the cream stirred often with a tinned metal plunger.

(4) The cream should be cooled with a water-cooler. Putting the cream in a tub of water is not sufficient.

(5) The surroundings of the separator-room and place where cream is kept should not be muddy.

(6) A plentiful supply of boiling water is necessary. Hot water should not be mistaken for boiling. Boiling water if carried from the house is useless for making the machine sterile.

There are many backblock settlers carrying out these essentials with good results, while often other farmers are complaining of the inability to produce a finest cream, giving as reasons the difficulties which have been overcome by others.

CAUSES OF SECOND-GRADE CREAM.

The following are some causes of second-grade cream, and in most cases they can be remedied by the famer.

(1) Badly arranged shed; (2) neglecting to cool cream ; (3) mixing hot and cold cream together ; (4) engine and separator being in same room; (5) failure to clean vacuum-pipes and vacuum-tank, and to leave vacuum-tank open when not in use;. (6) dirty rubbers and milk-pipes (7) putting rubbers in stagnant water (8) lack ' of ventilation in separator-room (9) muddy . surroundings near separatorroom (10) not removing lids and not washing and scalding cans immediately on return from factory (if) use of rusty cans arid tinware; (12) using separator-room as storeroom ; (13) use of carbolic disinfectants (14) skimming too thin; : (15) neglecting to scald tinware ; (16) sour skim-milk barrels ; (17) not washing the separator

after each use ; (18) keeping cream too long on farm ; (19) standing cans < in sun awaiting conveyance ; (20) using a cloth for a strainer, or using a cloth for washing instead of a brush ; (21) using too small a separator ; (22) using milk from unhealthy cows, or separating too soon after calving (23) flushing out separator with hot water after separating; (24) using a teat-salve containing an odorous disinfectant ; (25) pungent feed-flavours ; (26) milking with soiled hands ; (27) milking into unclean buckets.

BAD FLAVOURS AND THEIR CAUSES.

The following are a few flavours in cream easily recognizable, together with their causes : —

(1) Stale : This flavour is caused by keeping cream too long in an unsuitable place ; neglecting to cool cream ; mixing hot and cold cream together; skimming too thin and not stirring. A small quantity of this cream will flavour a whole vat, and it is always graded second grade.

(2) Maori bug: This is a smell like that which a Maori bug emits; when disturbed or crushed. A little of this cream will flavour a whole vat. The flavour may be caused by the separator not being property washed and scalded, yellowish slime forming on the tinware. Often a cloth more or less impregnated with the same slime is used for a strainer or in place of a scrubbing-brush. The flavour is accentuated by mixing hot and cold cream. Such cream should always be graded second, and in bad cases returned to the supplier. ■ '

(3) Fermented : One of the worst flavours. The cream is full of gas-holes, sometimes as large as a shilling. It often works like yeast and overflows the cans. Causes may be putting cream into cans which have previously held cream, and have not been property cleansed and scalded; neglect to cool cream; mixing hot and cold cream; or keeping cream too long. Such cream is always second grade.

(4) Tallowy: The cream tastes and smells like tallow. The flavour is caused by washing the bowl of the separator with slime in it, then washing tinware in the same water and not scalding afterwards ; putting cream into a warm can ; or standing cream in sun ; contamination from sheep-skins or harness, or various stores in dairy ; washing the separator only once daily.

(5) Curdy or cheesy : This is a smell and taste resembling bad cheese. The causes are skimming too thick and not cooling ; taking up taints from stores in the dairy, or oil and spilt milk on the separator-stand; bad ventilation; keeping cream too long without stirring.

(6) Sour : The cream tastes sour to a disagreeable extent. The causes are skimming too thin, and not cooling ; keeping the cream too' long on the farm in a warm atmosphere ; the presence of skim-milk barrels in close proximity to where the cream is kept.

(7) Milking-machine : This flavour is caused through not cleaning rubbers, vacuum-pipes, tank, and releaser, or from perished rubbers or it may be that the exhaust from the vacuum-pump is discharged

too near the milking-shed, so that the discharged air is redrawn into the system when the teat-cups are being put on the cows.

(8) Kerosene and benzine : Flavours caused by having the separator or releaser in the engine-room; kerosene or benzine stored in the dairy ; smoky kerosene-lamps : exhaust from engine not being' carried to leeward so as to avoid fumes being drawn into system when teat-cups are being placed in position on cows’ teats ; using benzinetins as buckets ; using roof-water for washing when exhaust is discharging through roof ; using water out of the circulating tank for washing purposes.

(9) Carbolic : Flavour caused by using odorous disinfectants in shed, or odorous salve on cows’ teats.

(10) Metallic : Flavour caused by cream taking up iron or copper after being put into cans or other tinware, such as milk-vat, separator, &c., with parts devoid of tin and perhaps rusty. .

(11) Ropy: The cream lifts in strings. Caused by unhealthy cows, or cows drinking stagnant water.

(12) Rancid : Caused by chemical changes brought about through lack of cleanliness, and high temperatures.

(13) Cowy: Due to using milk too soon after calving; bad drainage in cow-shed ; cows in ill health.

(14) Musty : Caused by cream being kept in a wooden building with no ventilation ; decaying timber in separator-room.

(15) Slimy : Caused by using too small a separator. The bottom plates become dogged with slime, a certain amount passing into the cream. (Flushing out the bowl with hot water when finishing separating causes slime to pass into the cream ; use skim-milk to flush bowl.)

(16) Cow-yard: Caused by muddy surroundings; manure-heaps ; bad drainage; smells drawn in through teat-cups : leaving used overalls in dairy where cream is kept.

(17) Buttercup: Flavour prevalent in. early spring, and is not unlike radish —sharp and pungent to the nose. Cream generally of high colour.

(18) Watercress : Cream with this flavour smells like acetic acid. More troublesome in the autumn.

(19) Pennyroyal: An easily detected flavour, smelling like the plant.

(20) Turnips, rape, kale, chou moellier : Strong undesirable feed flavours, always causing second grade.

Corticium ■ Disease of Potatoes. Experiments with corticium disease were carried through the season of 1927-28 by the mycological branch of the Fields Division, with the result that a Considerable quantity of tubers free from this disease was secured. In plot experiments appreciable increases in yield were obtained over untreated potatoes. Dry dust treatments on the control of this disease proved under field conditions to be useless, even the best of the treatments having a high percentage of viable sclerotia present when the tubers were lifted.