TESTING THE GRADE

Bay of Plenty Beacon, Volume 10, Issue 19, 2 September 1946, Page 8

TESTING THE GRADE

BACTERIOLOGIST’S REPORT

DAIRY COMPANY’S REPORT The following is lhe report of Mr F. S. Hodson, Bacteriologist to the Rangitaiki Dairy Company as submitted and read to the annual meeting of suppliers last week:I have pleasure in submitting the Annual Laboratory report for the season 1945-46:

Milks tested 7,161; Creams 511; Buttermilk 64; Waters 37; Bulls 8; Vacuum gauges 7; Factory and miscellaneous 344. Total 8,132. Vaccine issued 87,900 c.c. Eighteen herds comprising approximately 2,000 cows were under Herd Control for mammitis. Towards the end of the season and beginning of this season the demand for vaccine very much increased. I am pleased to report-that treatment of the new pipe line for conveying buttermilk to the. pig farm was very successful and no . evidence bf zinc poisoning was found. Since the old line has been disconnected and removed and the usual one part of molasses per 200 of buttermilk has been continued I have not heard of any complaints. V . With the co-operation of the Factory Manager, Mr Becker, stock cleaning solutions have been jused in the factory and prove more efficient and economical in use. At times special treatment of apparatus has been worked out and resulted in marked improvement. Dr. McDowall, Chief Chemist of the Dairy Research Institute, paid a visit to the factory and was' so interested that he came at 4 a.m. to see the start of the work and followed it through. Visits from experts such as Dr. McDowall are much -appreciated and helpful in interchange of ideas and technique. I am pleased to report that my modification of the methylene blue test to make it applicable to cream testing has been published in the London Dairy Industries Journal, occupying eight pages. Mr Batt of the Dairy Division, and Mr Lee have spent some time here checking up on this test and have commented very favourably on the results as it will help in deciding where the Dairy Instructor needs to visit to improve the quality of the cream supplied. Some time ago Dr. Moir, Chief Chemist of the Dairy Division, Department of Agriculture, called my attention to a new test —the Resazurin dye test. I have carried out hundreds of check test with this and the blue test and find it an excellent test but not nearly as satisfactory as the blue for checking a large number of creams such as a lorry load. For milks, it will probably in time supercede the blue.

I have, however, found the resazurin test of the greatest value in checking the bacterial state of the cream going into the churns and the buttermilk after churning. This will indicate the cleanliness of the churn or cream vats etc. An excellent hot water system for cleaning the vats and churns ’ was installed by Mr Rutherford and carried on by Mr Becker and has proved most satisfactory, so much so that I ran special checks on a day’s churning to illustrate a paper I was to give at the dairy Science Conference at Massey College and all the results were practically sterile. We have not had an unfavourable butter bacterial count from the grading stores for a very long period. During this season, by utilising the old Thymol blue test outfits, I have simplified the- sampling on the factory stage of cream samples for the blue test. I have always had the co-operation of the manager and factory staff whenever I wanted samples and this method has made the sampling quicker and easier. I applied for membership of the British Society of Dairy Technology and have been notified that I have been elected a member. I have just returned from a conference of the N.Z. Dairy Science Association at Massey College and gave a demonstration of the Air release dropper tap which allows the air to be expelled from the teat cups when they are dipped to wash or sterilise. I also gave a demonstration of our new method of sampling on the stage and a short description with results, of our system of checking up the cream and churns and buttermilk with the resazurin test. Many valuable contacts are made at these conferences and much useful information exchanged. “Gadgets” on milking machines are not favoured except that it is considered that some means of showing when the rate of flow of the milk is decreasing would greatly assist in the matter of not leaving cups on longer than necesary. At the conference, a new method of cleaning machines without-boil-ing water was described using dilute caustic soda. The method has been tried successfully but entailed more work and time. I have the particulars should power shortage render its use necessary. In conclusion I wish to express appreciation of the assistance and co-operation I have had for many seasons from Mr Thomson, the Veterinary Surgeon.