THE DISCOLORATION OF CHEESE.

Otago Witness, Issue 2051, 15 June 1893, Page 6

THE DISCOLORATION OF CHEESE.

At a meeting of the Cheshire Chamber of Agriculture, held in March lasb, a report ort experiments in oheese-making, conducted at the Dairy Institute, Worlaston, was presented by Mr A. Smebhani) I^.R.S., and ordered to be printed and circulated. The following is an abstract of the paper, in the course of which the writer stated that — *' From experiments at Worlaston during 1891, and from the experience gained during the summer of 1892, it was abundantly evident that the character of the resulting cheese was largely determined by tiutsids influences, and with a view to determine whether this was correct, and further, whether such knowledge might be applied to the production of good cheese, he instituted what might be termed inoculation experiments." Inthefirstplace,heexperimentedwithaslightly discoloured cheese, and small though it was in comparison with the whole bulk of the milk, the effect was very extraordinary, and the resulting cheese was finally pronounced to be worth lees by 9s per cwt than the average cheese made. This experiment abundantly proved the detrimental effect which was produced by the intro* duction of wrong ferments, and was an exemplific«tion of the evils which must ! necessarily attend the contamination of milk even with very minute quantities of decomposing cheese of other fermehting substances. That a few ounces of spoiled milk added to [ nearly 80gal of pure milk should reduce the f value of the resulting cheese to such an extent waa to his mind eloquent testimony of the necessity for such scrupulous cleanliness in every operation, both inside and outside the dairy, that the introduction of foreign ferments became an impossibility, or was reduced to a vanishing point. It was because these ferments were invisible and insidious that the true cause of much of the inferiority in cheese had been overlooked; and he was therefore constrained, in, no measured terms, to counsel all those who Were not getting the highest prices for their cheese to commence their investigation at the fountain head, and to satisfy themselves that no dirt, and particularly no dirt containing decomposing milk, found its way into the vat. The conclusions to be drawn from these experiments were (1) that, by the artificial introduction of ferments, the process of cheesemaking might be hastened at will; (2) by the use of a contaminated ferment it was impossible to make a really first-class cheese, even when ill-effects were to some extent counteracted by rapidly cooling the evening milk; (3) by the introduction of too large a quantity of a comparatively pure ferment withont previous cooling of the milk the process went on so rapidly that the textures became hard and the cheese was seriously deteriorated in value; (4-) when a pure ferment was used, and the fermentation was kept under control by rapidly cooling the night milk, net only was the texture good, but the flavour of the cheese was all that could be desired. The experiments afforded a striking confirmation of the conclusions at which he arrived as the result of the previous year's experiments at Worlaston, and he was more than ever convinced that one of the secrets of success in cheese-making was to keep under complete control the fermentation in the night's milk. This must be accomplished primarily by the aid of scrupulous cleanliness, and secondly, by the proper regulation of the temperature at which the night's milk was allowed to remain. Unless -these two points were attended to he was bold to affirm that the manufacture of cheese must ever be attended by comparative failure and be a constant source of disappointment and despair. In only two instances was an attempt made to ascertain the effect of rapidly cooling the night milk without introducing any special ferments. In the first instance, the colour was uniform, but not bright, and the texture was weak, the cheese being valued at 9s per cwt less than the average made .by Mr JSiddorn ; while in the other, with a slight tendency to weakness, the cheese was valued at Is per cwt more than the average. It was obvious that from so limited a number of experiments, giving such different results, no conclusions could be drawn; but he thought there could be no doubt, looking at the experiment in the light of the whole of the work done, that under ordinary circumstances, especially in the spriDg and autumn months, too rapid cooling of the evening milk was apt to check fermentation in too great a degree, and that when the cheese came to be made on the following day the fermentation was likely to be slight and the cheese consequently weak. As time and temperature were the two controlling factors in the development of ferments, and as each degree above 30deg Fahr. had an appreciable effect upon the rapidity of growth, it must be evident that the nicest care must be exercised in the cooling process, lest in avoiding too rapid development the other extreme was reachsd and the cheese be spoiled in another direction. Of all the detects in Cheshire cheese that known as discoloration was perhaps the most pronounced, because it was the most perceptible to the eye, and by offending it caused a material deterioration in the selling price. He had doubted for some time whether this deterioration in value was due wholly to the uninviting appearance of the cheese, or whether inferiority of flavour was associated with it; but he had come to the conclusion that the ; flavour of the discoloured cheese was never equal to that of a really first-class cheese, and he ,was forced to the conclusion that the deterioration in the market price was attributable not only to the unpleasant appearance, but also to the lack of the peculiar flavour which gave a firat-xjlass cheese its high value. When once the ferments producing this unwelcome disease had been introduced into cheese, all the skill and all the care of the most experienced cheese-maker in Cheshire could not entirely prevent evil results from manifesting themselves. If he were a farmer and wished to prevent i his disease in his cheese, he would disinfect his c airy and shippons, lime wash the surface of the walls, and pay very special attention to the cleanliness of the cows and the utensils used in the manufacture of cheese. When it was remembered that these eecret foes were minute beyond all conception, aud floated about in the atmosphere, it could be readily understood that no ordinary methods would effect their complete removal, and that the most drastic measures must therefore be adopted. Like all ferments, those causing discoloration require proper food, and developed most rapidly within certain degrees of temperature. Hence it could be readily understood that, given the entrance of the discoloration producing bacteria in equal numbers, the extent to which the evil would spread in the resulting cheese would be regulated to a considerable extent by the conditions under which the cheese was manufactured. Amongst the causea which might aggravate the evil were improper temperature in the cheese vat; imperfect griuding, causing unequal distribution of whey in the cheose; uneven or exoeasive heating of the cheese oven, preßß house, or cur-

Koxlous Weeds.