MILK TESTING

Bay of Plenty Beacon, Volume 6, Issue 4, 14 September 1942, Page 6

MILK TESTING

HERDS ON THE RANGITAIKI

BACTERIOLOGIST'S REPORT

Mr F. S. Hodson, bacteriologist to the Rangitaiki Plains Dairy Company, reported as under to the an-r nual meeting of suppliers at Edgecumbe last Wednesday:—

Milk tested 15,977; Cream and butter 288\; Water samples 97; Bull tests 7; Vacuum gauges 13; Miscellaneous and Factory 428; Vaccine propared and issued: 29,0001 c.c.

Twenty-seven herds comprising 2251 cows were under the herd control and in a number of eases marked improvement resulted and with the exception of four herds, the disease was kept, under control. I',t appears to be the worst season since 1933/4. The vacuum- gauge testing should be carried out periodically bj r all suppliers especially as it has such an important bearing on mammitis and the testing is free.

During the season trouble occurred with the buttermilk supplj r to the pig farm. Tests taken located the trouble and the method of rectifying it. Testing solutions l'or both the Butter and Cheese Factories have been prepared in the Laboratory. Just prior to the closing of tlic cheese factory I obtained a small supply of a new dye called Resazurin which for milk is superior to the methylene blue test but which has not been used to any great degree in N.Z. as a practical means of differentiating good and bad milks but which is being used more and. more in England. We used it in conjunction with the curd test, and Dr Moil* the Dairy Chemist of the Dairy Division, was very satisfied with our results as lie has been a keen advocate of the usefulness of the test. In my opinion the methylene blue test is still the better test for creams but the rcsazurin better for milks.

Mr Connery, the Manager of the Cheese Factory, Avas very willing to co-operate in any way that would be beneficial and I was looking forward to closer co-operation and regret very much the closing of that branch of the company. I also wish to thank Mr Rutherford, for his cooperation and attention to matters which tests suggested would improve conditions in the factory plant. Tests have also been carried out in collaboration with Mr Thomson in connection with animal samples.

Pig Farm and Buttermilk: Complaints were received from the farm manager that he did. not get consistent light good curd and that it went in a solid mass to the bottom and was decidedly unpleasant. He also suggested that soda from factory cleaning might bo getting in and also no factory cleaning solutions got in but that sometimes excess water did. Mr Thomson then suggested; chlorinating the whole pipe line as samples tested at the laboratory showed very heavy contamination of putrefactive organisms. This was done and matters improved for a short time.' Trouble again occuvrcd and appeared to be worse when buttermilk was diluted. A rennet forming bacterium was found to be present and appeared more active in the diluted buttermilk. The chief source of this contamination was detected in the pressure air tank and Avh.cn this Avas thoroughly chlorinated trouble ccashed and the right curd formed wliether buttermilk diluted or not. An alteration Avas made to enable the whole pressure tanfk to be filled with chlorine solution periodically. Spasmodic trouble still happened and the amount of molasses added was' .investigated and it Avas increased and added earlier so that there was enough molasses buttermilk to remain in the Avhole length of, the pipe line till next pumping. This keeps the pipe clean and encourages the growth of, the. clean lactic acid forming bacteria. One part of molasses in .'SOO of buttermilk appears to be satisfactory in keeping the pipe clean. When pumped into the tank this is diluted Avith fresh buttermilk so- that the pigs actually get much less actual molasses.