DAIRY SCIENCE

Manawatu Standard, Volume LVII, Issue 212, 7 August 1937, Page 11

DAIRY SCIENCE

NEW ZEALAND ASSOCIATION. CONFERENCE PROCEEDINGS. The ninth annual conference of the New Zealand Dairy Science Association has been in session at the Dairy Research Institute, Massey Agricultural College, during the past two days. In opining the conference the president, Professor AY. Riddct, welcomed visiting members and expressed gratification at the large attendance. He hoped that members would enjoy the papers and take an active part in tlie discussions.

The first section of the presidential address has already been reported in the “Standard.”

At the request of members, Professor Ikiddet continued tho address on Thursday evening. Dealing with Canadian dairying, he paid a tribute to the work of Professor Eagles in British Columbia, who, lie stated, was carrying out investigations of fundamental importance on the lactic acid, bacteria, in connection with British dairying, the president outlined the system of instruction, stressing . the fact that organised research was limited to three institutions. The work in progress at these institutions was reviewed, and consideration was then given to Continental dairying. The similarity between the problems of openness being studied by tho Dutch investigator van Beynum to our own problems of slit openness was indicated. Van Beynum, said the chairman, had come to the conclusion that a solution to the openness problem would only result from a study of the sources from which tho causative organisms reached the milk, and he, therefore, was at present particularly concerned with the types of bacteria taking part in ensilage fermentation. Otlier subjects covered by the speaker included the organisation of dairying in Denmark and Sweden and the problems encountered there in connection with butter. PAPERS READ.

Investigations on the variations occurring in the composition of butterfat from stall-fed cows on different feeds were described by Air G. A. Cox. lodine values saponification equivalents and Reichert-Aleissel values were determined on samples of fat taken weekly over a whole season. The only factor which was definitely correlated with the composition of tlie biitterfat was the environmental temperature. The alterations in butterfat composition, however, lagged behind the temperature changes by about a iortnight. Dr. AY. J. AA’iley read a paper on the acidity of butter. The relation of pH to acidity was explained and the influence of "acidity cm the flavour of unsalted butter, both where the acicl had been added as such and also where it had been developed by starter, was discussod.

Air J. D. Sargent described experiments upon tlio working of butter under partial vacuum. J lie amount of air removed from the butter and the consequent shrinkage depended on the vacuum employed. The influence of laciium working on the quality of the butter was dealt with.

In a paper entitled “New Alethods for Determining Iron and Copper in Butter,” Dr. G. AT. Aloir and Air E. D. Andrews pointed out the need for simpler tests for these metals than those at present available. An account of methods which might meet this requirement was given. On Thursday afternoon a symposium was held on starters and cheese-ripen-ing. Air J. G. Hunter explained in detail the technique necessary for the successful propagation of single strain types of starters, and went on to outline recent work on the characteristics of bacteriophage, including the resistance of the virus to conditions such as might reasonably be expected to obtain in commercial factories. Air I. It. Sherwood outlined the present conception of bacteriological changes in cheese. The origin of flavour in cheese and recent advances made in its control were discussed. The causative agents of slit openness and certain types of discolouration were shown to be lactobacilli. Dr. It. AI. Dolby indicated, the relation between pH of cheese and the commercial quality. He also traced the acidity changes which occur in cheese during manufacture and subsequent ripening. The technique employed in the bacteriological examination of export butter was described by Dr. G. AI. Moir and Air R. It. Russell. The result?

wdre reviewed together with their practical significance. Mr A. J. Wood gave an interesting account of growth factors in relation to bacteria. He mentioned recent work on the subject in America and on the Continent, and illustrated the dependence of various organisms upon the presence of these vitamin-like substances. ACIDITY IN MILK. The conference was resumed on Friday morning with a discussion on the accuracy of acidity determinations in milk, opened by Messrs W. G. Sutton and J. D. Sargent. Dr. F. H. McDowall indicated the desirability for standardisation of phenolphtiialein strength and the need tor ensuring the supply of accurate standard solutions of acid and alkali to commercial factories.

The effect of watered milk upon cheese manufacture and tile quality of the cheese was dealt with by Dr. Dolby.

Mr ,1. W. Vinten delivered a paper entitled “Fat Losses in Factory Skimming and Their Delation to Casein Manufacture.”

Butterfat losses in buttermilk were discussed by Dr. McDowall and Mr W. H. Udy. The most suitable methods of estimation of the fat were described and the errors inherent in each procedure were given careful consideration. llesults of extensive experiments on buttermilk from cream pasteurised by the flash method and by the vaereator were detailed. A discussion on the Babcock test for fat in cheese was opened by Dr. G. M. Moir, who also reviewed the accuracy of certain modifications of the test.

“Colour and Its Measurement” was the title of paper delivered by Mr M. S. Carrie. After dealing with the nature of colour, l\fr Carrie went on to describe instruments- eniployed in its measurement. In particular the principle and the uses of the ZeissPulfrich photometer —a most accurate instrument—were explained. Following on from the previous paper, Mr Carrie discussed the standardisation of cheese colour. The fallacies and inaccuracies in earlier work were exposed, and methods for the accurate standardisation of colour were detailed. The methods of standardisation evolved in this investigation

were applied, in particular, to cheese colour.

In ’ discussing the “Costed Cheese” system of payment, Dr. McDowall described the application of the system to 17 factories. The results clearly indicated which factory suppliers had been underpaid and which had been overpaid, he said. In many factories the discrepancies under the old system were serious, but application of the costed cheese system resulted in a fairer payout. A here, on the other hand, little injustice was being done to individual suppliers, use of the more expensive system was scarcely warranted.

The final paper of the conference was delivered by Dr. McDowall, who dealt with problems arising from the supply of high testing and low testing milk to factories.

At the conclusion of the conference a vote of thanks to those who hod contributed papers was passed. A vote of thanks to the chairman was carried In- acclamation.