CHEDDAR CHEESE MAKING.

Otago Witness, Issue 2387, 30 November 1899, Page 4

CHEDDAR CHEESE MAKING.

In carrying out his research wort, a notice of which appeared in our issue of November 16, Mr Lloyd and the Council of the " Bath and Wesl< " Society wisely decide d to have the cheese school frequently loca^d for a season at a centre where it had fcsen previosuly found difficult, if not impossible, to make good cheese. Prior to these investigations being commenced there were many farms or districts in England where the farmers found it all but impossible to produce good Cheddars. As Mr Lloyd puts it in his report : " There arc certain soils or farms in. England, especially in Somerset, upon which, if tradition can be believed, there are spectre signboards bearing the words, ' Good cheese cannot be made here.' Unfortunately, no one is able to see these signs except the tenant for the time being. But the belief in the inability to make good cheese on certain soils is so widespread, and the conviction that it is founded on fact is so atronjj that the subject received .direful in-

■quiry." With the view of dealing effeo* tively with these "spectre signboards," thq Cheese School was for three successive seasons located on farms where, according to local tradition, it was not possible to make good cheese. A careful examination of the ! soil on these farms and an equally cara-« i ful botanical examination of the pasture? was made on the opening of the school aft these places ; bub nothing abnormal was discovered either in the composition of the soil or in that of the herbage. The cause of the bad quality of the cheese formerly, i made on these farms had, therefore, to be looked for in other directions. In every case, the cause sought for was discovered*' In one case it was found that the taints ia the curd only occurred when the wind was in one particular " airt." Following up this scent, Mr Lloyd discovered that the earthenware drain pipe which carried the whey to a receptacle in the farmyard was a veritable culture-bed of malign bacteria, which were carried into the atmosphere of the dairy, and caused the taint in the cheese. In another case it was found that the taint in the milk was caused by the cows drinking water from a pond which was con-* taminated by the droppings of the -animals and other causes. The smell of a manure heap, placed too "ifaeai"; the dairy was frequently found to be the cause of similar taint. In this connection, Mr Lloyd directs" attention to the amount x)f mischief that may be done in a cheese-making dairy by means of flies. These insects have a way of alighting on farmyard manure : aiid all sorts of matter, "in the wrong place,'' and if they get Tnto the milk or on to the dairy utensils, or into the dairy, they carry with, them the injurious bacteria with which thei excrementitious matter is loaded. Mr Lloyd made numerous experiments, which clearly proved that the malign bacteria found in tainted milk had been introduced by flies. The necessity, therefore, for using a copious s\tpply of insect powder and fly papers in dairies and % byres is nt once ap-» parent. Mr Lloyd's -indictment of flies as a source of bacterial infection is confirmed by a report recently issued by tho Ontario Government of the annual meeting of the Cheese and Butter Association of Ontario. At this meeting, Dr Council, the eminent bacteriologist of the Queen's University, Kingston, read a paper on " Bacterial Infection of Cheese," in the course of which !he related how all the cheese in one i particular factory in Canada had gone ! v/rong, and on his being called upon to ! discover the cause of the trouble, he found i the origi mali vwas the putrid slime lodged in a gap between tho wooden boards of the floor. The bacteria found in this slime were tho same as those found in the tainted cheese, -and as the factory was" greatly infested with flies; there was no doubt that the mischief was caused by the flies alighting on the putrid] slime, getting their feet and bodies soiled., with, this bacteria-laden material, and then conveying the" infection direct to the, milk or to the milk utensils on wliich they alighted.' On this point Dr Connell says: "I think from' this instance it would be well in future fur cheesemakers, and, in fact, for all interested in this matter, to boar in mind the importance of flics in carrying material from point to point, and thus leading to infection. Bacteria from any foul drain or stagnant pool, or, in fact; from any decomposing material in the neighbourhood of "the dairy or exposed milk or milk vessels, might this be transferred into the factory or into the milk." COWS GIVING ABNORMAL MILK. ' The numerous bacterial investigations carried out by Mr Lloyd led to all but one of the bacteria causing taints in' milkbeing isolated, so that the source of the mischief was fully discovered. The practical results of these investigations go to emphasise the (importance of providing for the cows a thoroughly pure water supply, of ensuring the most scrupulous cleanliness in milking the cows And handling the milk, . and also of guarding in every possible way against bacterial infection from foul drains or putrid and excrementitious matter. v Mr Lloyd further points out another source of danger that has to be guarded against, and that is in regard to cows \\vhich give abnormal milk. At the Cheese School in 1898, it was found in the beginning of the season that there was something very wrong with the curd, so that the cheese made from it were of inferior quality. As the water supply and sanit;:ry condition of the buildings were all right, and no trace of bacterial infection could be discovered, it was resolved to subject the milk of every cow in the herd to chemical analysis. The result of this analysis showed that in the herd there were four cows giving abnormal milk, which showed an average of only 2.86 per cent, of butter-fat and 2 per cent, of casein, while the milk of all the other cows showed an average of 3.33 per cent, of bulter-fat and 2.57 per cent, of casein. The four cows which gave that abnormal milk were at once removed from the dairy, and the trouble with the curd at once disappeared. There was no external sign .of any disease or other peculiarity about these four cows, and their milk was well up to the average in point of quantity. Three of them were sold to a butter-maker, and their new' owner was surprised to find great -difficulty in churning the cream after these cows were introduced into the herd. This difficulty became so serious that the three newly-acquired cows were suspected, and on an attempt being made to churn tha cream from the milk of these cows separately, it was found that the cream was unchurnable. The result was that the attempt to make butter from the milk of these cows had to be abandoned, and the cows had to be fattened for the butcher. This experience emphasises the necessity; of both cheese-makers and' butter-maker.?, as well as milk-sellers, guarding against keeping any cows which give abnormal -milk. To guard against this danger, it is not necessary for the ordinary farmer Co be at the expense of submitting each.separate cow's milk to chemical analysis, aa practically the same result can be attained by the use of a Babcock or Gerber tester, either of which is quite handy to manipulate, and comparatively inexpensive. HOW TO TEST I'Olt ACIDITY. Among many important scientific points raised by _Ii; Lloyd, one of ,great inters-*

to practical' cheese-makers is the new and very simple, as well as very accurate, method which he has introduced of testing acidity. The hot iron test, as used in the Canadian system followed in Scotland, is not at all an accurate one. As Mr Lloyd says: "The length of the* threads so obtained is used, by the cheese-maker as a guide to the acidity of the curd ; but how far *ib actually depends on the acidity or how far it may be influenced by the moisture or fat in the curd does not appear to have been accurately determined. The greatest drawback of all to the hot iron test is the uncertainty as 1 to the heat of the iron itself. It is evidently impossible, by the use of an}' uncertain standard, to determine with accuracy either the acidity or any other condition of curd." The want of a simple and accurate system of testing for acidity in milk and curd has long been a felt want among cheese-makers, nnd some years ago the Highland and Agricultural .Society offered a premium of £100 for a satisfactory system of testing acidivy in cheese-making. Only a few competitors took a part in the competition ; and the award was withheld on the ground that none of the systems submitted were of sxifficient merit to warrant the premium being awarded. Now, however, cheese-makers 'have in -the acidity test elaborated by Mr Lloyd a simple method by which the acidity in milk and curd may bevmeasured with mathematical accuracy. A suitable chemical, apparatus which is fully described and illustrated in Mr Lloyd's report, is used for the lest, which is made by means of a standard solution of an alkali (soda) and .of a substance (phenol phthalein), termed ,;.n ' indicator, which changes colour according to whether a solution is acid or alkaline. On this point -Mr Lloyd observes : "The acidemeter is no longer confined to purposes of investigation. It has been placed upon the market, and there are many cheese-makers now employing it daily. The evidence which I have received from cheese-buyers tends to show that its use has resulted in a considerable improvement of the cheese. The use of the acidimeter might be taught with advantage in the schools of every county where cheesemaking is carried on." |

SCIENTIFIC HANDLING OF RENNET,

Another most important matter is in regard to the rennet. Microscopical and bacteriological examination have shown that numerous bacteria, as well as some yeasts, are present in the rennet, even when the rennet is a good quality. It follows, therefore, that if bacteria which are not injurious to cheese-making are capable of living in rennet, others which would be injurious might also find in it sufficient nutriment for their existence. It is necessary, therefore, to ensure, not only that the rennet is pure, but that it is kept in such a place and such a manner that it is not liable to become contaminated. Mr Lloyd stated that a bottle with patent stopper similar to those used for sterilised milk is an admirable receptacle for the rennet employed in the dairy. After due steps have been taken to ensure that the rennet is not only pure, but is kept pure, the next point is to measure the proper quantity of rennet, and this is one of the most important points in cheesemaking. It is impossible to lay too much stress upon the importance of using the correct quantity of rennet. If rennet be added in excess, a hard curd will be obtained ; and, when insufficient rennet is used, a soft curd ensues, causing while whey and a considerable loss of fat. A good rennet extract will cause nine thousand times its own volume of milk to set in a. firm curd in 45 minutes. In view of the remarkable strength of the rennet extract, it is most necessary to have a very accurate method of measuring out the exact quantity. Some cheese-makers use merely an old tea-cup for measuring the rennet, andj no doubt, they wonder that they do not get the same results from their cheese day after day. Others use the ordinary medicine glass, but this is not nearly accurate enough. At Mr Lloyd's suggestion, Messrs Townson and Mercer, of 79 Bishopsgatc street, London, have made a 2oz graduated glass cylinder measure, having 200 divisions, each of .which represents a hundredth gmrt of an ounce. With this appliance it is easy to accurately measure out the necessary quantity of rennet, while to calculate Itvhat this quantity will be is very simple.

SCOO MtfCH RENNET IN SCOTCH! CITEDDAHS.

A yery striking point of difference befcween the Canadian (or Scottish) and the (English- systems of Cheddar-making is to 4>e found in the amount of rennet used. In the Canadian (or bcot/tish) system the 'tfenneb is used in the proportion of loz to 27gal of milk, or 1 £art of rennet to 320 parts of milk ; whereas in the English Systems the rennet is used in the proportion of one part of rennefe to 9000 - "parts jof milk, this being less than half the Amount used by Scottish makers.. On ihJg

point Mr Lloyd emphatically holds that this excess of rennet in the Canadian (or Scottish) sytem is detrimental to the manufacture of cheese of the finest quality." Mr Lloyd gives details of experiments which he made by way of determining why it was that under the Canadian system the cheese was made in so short a time. On this point he says:

" This experiment was made with milk having an acidity of .22 per cent. To obtain this acidity great care had been taken in the ripening of the evening's milk, for it seemed absolutely necessary to obtain it if rapid results were to be secured. On the other hand, being convinced that the use of an excessive amount of rennet was detrimental to the manufacture of good cheese, only one part of rennet was added to 7000 parts of milk. In all other repects, the cheese "was made on the Scotch eystem. The acidity of the liquid from the curd rose rapidly after it was taken to the cooler. The curd was ground at 1.30 /p.m., left to cool, and vatted at 3.30 ■p.m. The acidity of the liquid from the press was 1 per cent. The cheese was good, but not so good as the best English Cheddar cheese, being rather too dry. The chief peculairity of cheese made on tho Scotch system is their dryness. The analysis of the curd showed that it contained only 37.60 per cent, of watefr, whereas the average composition of the cheese made in the same month at the 'Bath and West ' School showed 40.12 per cent, of water. Similar results have been obtained from curd sent from Scotland; they all contain less water than should 'be present in a curd which will ripen into an excellent cheese. ■ This is a natural result of using a large proportion of rennet, coupled with a, high scald." Confirmed as they are by the convincing facts that English Cheddars, because of their excellence, command the highest market rates, Mr Lloyd's teachings of the principles to be observed in the manufacture of this description of cheese may be studied with much advantage by makers in this colony.