Transactions of RHASS Volume 1940 - Page 069
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| Year | 1940 |
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| OCR Text |
126 AGRICULTURAL RESEARCH IN SCOTLAND IN 1939. A number of milk producers have introduced the practice of irrigating the units with strong chlorine disinfectants. Such procedure in itself has been found quite unreliable as a means of insuring low bacterial numbers in machine-drawn milk. The chlorine rinses can only be regarded as useful in milk production provided the surfaces to be sterilised are first rendered free from all traces of milk and extraneous matter. The persistent failure of milk of low bacterial count to conform to the coliform standard on farms exercising a high standard of cleanliness has been traced to the leakage of contaminated farm water supplies into the milk during its passage over the cooler surface as the result of defects in cooler construction. M astitis.—Failure on the part of the herd owner to deter- mine the exact nature of the causal organism present in the udder of his infected cows has been shown to be responsible for the very minor success attained in the use of certain chemical agents used as a curative treatment for mastitis. In many cases, large numbers of disease organisms have been found persisting in the udders of improperly treated cows, emphasising the great importance of correct methodical diagnosis before any curative treatment is undertaken. The Density of M ilk—A comprehensive investigation under- taken to determine the exact weight of a gallon of milk as received at farmers’ creameries throughout the country over a prolonged period afforded an opportunity to examine the composition of the milk delivered. While there would seem to be no difliculty in maintaining the fat requirement of the Sale of Milk Regulations and the Marketing Board Contract, it has been found that one sample out of every four of the hundreds of samples of mixed herd milks failed to comply with the solids-not-fat requirement of the Milk Regulations. Cream—The examination of representative creams, taken from both wholesale and retail sources, for bacterial numbers, acidity and keeping qualities, was continued throughout the summer of 1939 with the object of obtaining information to assist in the elaboration of cream standards which the com- mercial cream trade could reasonably attain. The rate of acid development in creams of varying fat percentages main- tained within varying temperature ranges and the relationship between bacterial numbers and the rate of acid development have been investigated. Deterioration of cream and the appearance of off-flavours would seem to depend more on the types of organisms than on the total numbers present in AGRICULTURAL RESEARCH IN SCOTLAND IN 1939. 127 the cream, which, in turn, is largely governed by the cleanliness 0f the milk from which the cream supply is obtained. Batten—The influence of sprouted maize in the ration of the cow on the quality and manufacturing properties of the milk produced was examined when sprouted maize supplanted mangolds as part of the succulencc in an experimental ration. The flavour of the butters made from the milk of cows on the mangold ration was invariably superior to that of the corre- sponding‘ butters from cows fed sprouted maize. The Influence of the maize was more markedly shown on the keeping properties. The longer the period during which thesprouted maize was fed the shorter were the keeping propertles of the butter. A distinct tendency to develop rancidity was a feature found in all the experimental butters made from the milk of the cows fed the sprouted maize. . The department carried out a full examination of the composition and keeping properties of a comprehensrve series of butters drawn from the creameries of registered National Mark Butter manufacturers and subjected to long periods of storage in an investigation undertaken by the Department of Agriculture for Scotland. The striking effect of the degree of acidity in the cream at the time of churning on the keeping quality of the butter was most clearly demonstrated, the butters from the low acid creams gaining in all cases the highest marks allotted for flavour in the final butter grading. Distinct variations in the amounts of salts and moisture and the numbers of bacteria and other organisms were found not only between the difierent creameries participating in the experiment, but also between different lots of butter from the same butter manufacturer. The manufacture of butter on the limited scale as practised on the small farm has increased considerably with war condi- tions. Standard methods of buttermaking involving the use of starter are not practicable, with the result that the resulting product lacks the flavour and keeping properties of first quality butter. A new method of handling the cream in which pasteurisation and starter are not required has been success- fully elaborated in the department. The bacteriological aspects of the factors involved in the prevention of cream and butter deterioration by the addition of salt to the cream during its period of collection have received considerable attention. The method is of special application during the winter months when butter from gathered cream is apt to show the presence of off-flavours and lack sufficient keeping properties. |
| Title | Transactions of RHASS Volume 1940 - Page 069 |
