H.—34,

REPORTS OF RESEARCH COMMITTEES OF THE COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH. DAIRY RESEARCH INSTITUTE. Dairy Research Management Committee : Hon. Sir George Fowlds (Chairman), Mr. A. Morton, Mr. J. Murray, Mr. T. A. Winks, Mr. W. lorns, Mr. Dynes Fulton, Mr. Quentin Donald, Professor H. G. Denham, Dr. C. J. Reakes, Mr. W. Singleton. Director of Research : Professor Wm. Riddet. During the past dairying season the Dairy Research Institute has continued to make a close study of problems associated with the manufacture of butter and cheese. The following work has been engaging its attention : — (a) Butter: — (1) The effect of different rates of cooling cream on the spreadability of butter made therefrom. (2) The effect of adding starter to cream —a continuation of the work of previous seasons. (3) The effect of chemical sterilizers and chemical sterilization of the factory plant on the quality of the butter. (4) Determination of the usefulness of certain new types of paper and metal foils for wrapping butter, and the effect of metallic contamination arising therefrom. (5) The cause of changes in surface colour of butter during storage. (()) The treatment of Pinus insignis as a possible timber for butter packages. (/;) Cheese: — (1) Continuation of work on "openness" in cheese. (2) Repetition of previous work on the difference between high- and low-testing milk and between raw and pasteurized milk for cheesemaking. (3) The influence of variations in the process of manufacture and the control of acidity and moisture on the quality of the cheese. (I) The factors bearing upon the outbreak of discoloration in cheese last season, and study of the problem from bacteriological and chemical viewpoints. (5) Starters : Methods and apparatus for keeping starters in the factory ; causes of failure and methods of prevention ; types of starter for production of flavour in cheese. (6) The significance of acidometer readings in cheesemaking and the chemistry of cheesemaking. (7) Cheese-bandages : The effect of different qualities on the shape and quality of the stored cheese. (8) The usefulness of different methods of grading milk for cheesemaking and factors influencing the yield of cheese. The following statement briefly summarizes results to date, bearing on the above. A certain amount of research work is still too incomplete for progress reports to be made. Butter. Flavour. —Certain potential markets in Great Britain have expressed a preference for a product possessed of a distinct lactic flavour characteristic of some European butters. Trial shipments of butter made during the year from selected fresh cream, pasteurized in the ordinary way, but of such fresh quality and low acidity that no neutralizer was necessary, showed that it was possible to supply the requirements of such a market. Overseas buyers who examined the butter and commented very favourably on it made special reference to the entire absence of undesirable neutralizer flavours which are observed from time to time in New Zealand butter. It was later found possible to improve the flavour still further by the addition to the high-quality fresh cream of a very small amount of starter, which serves the purpose rather of a flavour improver than an acidifier. A most important feature of this work is to ensure that only very high-quality fresh cream is used. This demands, in factory practice, the daily delivery of fresh cream. Spreadability. —Experiments indicate that butter made from cream which is cooled relatively slowly in the last stages of the process is more spreadable than that made from cream cooled very rapidly after a temperature of about 55° F. is reached. Efforts, however, made to improve spreadability showed that great care needs to be taken to avoid greasiness of body. Further experimental work is necessary before the technique can be applied in factory practice. It has also to be pointed out that any modification in present methods of manufacture should only apply to butter which would be marketed in Great Britain during the winter months. Cream-quality. —The trial shipments have shown that, on the average, finest-grade cream low in bacterial numbers when received at the factory produced butter of better keeping-quality than did finest-grade cream high in bacterial count. Salt. —In assessing quality, the overseas buyers showed themselves markedly sensitive to salt ; they frequently preferred butter with a salt content less than the legal limit. It is well known that different districts in Britain vary in their preferences for degrees of saltiness in butter, hence it is encumbent upon local buttermakers to study the needs of their special markets before adding salt too generously in their attempts to secure a maximum overrun.

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