THE SPONTANEOUS G0AGULATION OF MILK.

Waikato Times, Volume XVIII, Issue 1546, 1 June 1882, Page 2

THE SPONTANEOUS GOAGULATION OF MILK.

+ The following essay on the above subject is from the pen of Mr Horace Walpole, the newly appointed manager of the Te Awamutu Cheese and Bacon Factory. It was delivered by him to the Briagolong (Gippsland) dairymen. We are indebted to Mr Walpole for the manuscript ;—lt; — It has happened every now and then in cheese factory practice that milk has been found to coagulate without the presence of any sensihle avidity. Well authenticated cases of this kind have occasionally appealed in the agricultural papeis of America and Victoria, and they have also been mentioned by dairymen at their meetings for public discussion. Their occurrence has been the occasion of surprise, and a good deal of wonder as to the cause of such a phenomenon, but no light has been shed upon the subject further than to find that there is always something the matter with the milk so affected. Cheese makers in Victoria and Gippsland, also m America, have reported several cases in which milk standing in a large body in the manufacturing vats through the night has been found in the morning to be more or less coagulated, and yet perfectly sweet. The curds thus formed have been wanned and cut, treated the usual way, and made into cheese, which did not appear, when cured, materially different from cheese made with the use of rennet. There was no indication of acidity in the working of the emd, or in the curing of the choes-e more than is usual in the curd of sweet milk coagulated with rennet. I have met with a good many cases of this kind of spontaneous coagulation, in which the tendency to acidity was not greater than is usual. In one case milk, as soon as drawn, was put "into a closely covered can, and after being carried m a w.iggon for a quaiter of an lioiu cm died in a few minutes upon being warmed to niuety degrees. This sample was not only perfectly neutral when it coagulated, but the curd and whey remained neutral six hoius before they would respond to an acid test. The causes which brought about these seemingly strange results are neither new nor very materially differrent from those which produced ordinary coagulation. Milk is composed of water, caseine or cheesy matter, albumen, sugar, _ and certain mineial matters, all joined in a chemical uuiuu. Butter is an outsider so tar as this chemical partneiship is concerned, for it is only mechanically mixed or suspended in this liquid combination. The caseine is what becomes curd when it separates from the other members of the partnership. It is attached to the rest of its companions by a very ieeble affinity, and becomes detached from them easily. A slight change in the mineral matter by the action of an acid, or in the sugar by the action of yeast is sufficient to break oft its connection with the compound, when it becomes a solid instead of a liquid, and appears as we see curd in cheese-making, and loppered milk. A shock of electricity may by changing the elective affinity of some one of the elements produce the same result. Wlien milk is left standing exposed to the air two varities of yeast are active in producing the coagulum. There is in milk, as has been before explained, when it comes from the cow, a very small quantity of yeast, similar to that in rennet. This multiplies, and would, in time, become sufficient to curdle the milk alone. Besides this, there is the lactic yeast, that is fiom the air ; that would also produce conciliation alone, but the two act together and produce coagulum sooner than either would acting by itself. The lactic yeast produces the greater effect, but that the curding of the milk is helped along, and hastened by the aid of the "former may be known by scalding the new milk, when the yeast, born with the milk, will be killed, and the coagulation will come from the souring alone, but about one-third more time will be 1 equii ed to effect it. It is a fact which must have been noticed by almost every one who has the care of milk that it does not always coagulate with the same degiee of sourness, which may be accounted for by the varying quautity of yeast similar to that m rennet. The influence of the ferment in new milk vaiies accoixling to the treatment of the milk and the health of the cow from which it is taken. If new milk is covered up so as to prevent the odor from escaping, it will very much facilitate the action of the rennet yeast ; agitation also helps it along. The health of the cow varies the quantity to start with. Any circumstance which produces a feverish condition in the animal will increase the coagulating agent in her milk, in proportion to the amount of fever. The feverishness produced by eating too much, or improper food ; by drinking stagnant water ; by worrying with dogs, or by exposure to a hot sun, will so increase the rennet yeast as to make the milk coagulate upon the first approach of acidity, or even before, when without this extraordinary amount a deeper souring would need to be developed befoie curding would result. These are general principles that relate to the action of milk ereiywhere, and are worthy the careful attention of all concerned iv any way in the production or haudliug of milk. They cover the cause of the premature thickening of the milk in our factories in Victoria. Seveial samples of thib spontaneously coagulating milk have been analysed, and in every instance a lack of butter and sugar and an excess of albuminoids was found, indicating a feverish condition in the cow. Some of the dairymen in Victoria who had not running streams on their farms, supplied the defect with what are termed, "pond holes." A large_ cavity is excavated in some low place which fills with water in the spring and remains through the season. The sides are made sloping so that the cows can easily get clown to the water to drink. In hot days they love to wade into the water and stand there to protect their legs from the flies. Of course, the water gets full of filth and becomes green and putrid, and full of miasmatic matter that would make any person sick to drink it. How anyone with common sense could for a moment suppose that such water would make good milk and promote heulthfulneas in his cows it is not easy to imagine. The milk which curdled so soon came from cows which drank from such a pond in January near-my factory in Gippsland. No wonder that they were not in good health, and that their milk was abnormal, and yet some of these dairymen could not understand what had effected their milk, and 1 came t6 me to know the cause of want of quality in their milk. Even every odor that comes in contact with milk is grasped and taken in at once,;, and its grasp is never slackened; once taken in,it isther,e permanently, and' the seeds of every ferment that' touches' its^surf ace finds such a fertile soil to flourish in that rsiey r $iey spring at once into vigorous growth, 'and multiply; and,' quickly t ': ", leaven" tkfej whole lump." ;Ttie Lmifai cites*-" 'instances ."W^M^%sH „%*£ J^" stood & showtime 'iiijjhe pf^lribWofiper-' ' sonVsick .wiM typl/oid fiver ox \iep^and~; ?fr^:th'efsmail.TorX^%fj^ir|^J^eBj "as"'effectuallv.^'itiu©^^rB6ns j fnenioel^es J '

smoking • lamp Vwill sodn do ,>, the same. This ' may seem like " rJ descending to little things, but it must be remembered ! that it is the sum of such little things that determines whether the products of the dairy are to be sold at cost, or below, or as a high priced luxury. Many other changes occur in the milk room. The souring process once begun continues till the sugar is converted iuto acid. The whey begins to separate fiom the thickened milk, and the vinous fermentation sets in slowly, forming alcohol, which takes up the volatile oils, and the strong acid ferment preys upon the solid fats to the detriment of the quality and quantity of the bntter or cheese, if still permitted to stand -the alcohol is converted into . vinegar aggravating results. While these changes are going on, the micrococcus cells will be slowly decomposing the cheesy matter, and carrying it on to putrefaction. These are some of the changes which are ever progressing under the eye of the dairymau, and he who can most successfully direct and control thezn is the one who reaps the reward.