MAINTAINING QUALITY

Bay of Plenty Beacon, Volume 7, Issue 4, 3 September 1943, Page 3

MAINTAINING QUALITY

CONTROL OF DAIRY PRODUCTS BACTEROLOGIST'S REVIEW The following was the Bacteriologists (Mr F. S. Hodson) annual review at the annual meeting of the Rangitaiki Dairy Company's suppliers last Wednesday:— The I'olloAving test, summary.,.wilT indicate the extent of operations over the past season: Milk tested 17.1.10: Cream tests 171; Waler tests 49: Bull tests 17: Vacuum gauges 12; Factor}- and miscellaneous' 173. Total 18,1-11. Vaccine issued 09,200 ee. Some four herds comprising 3-115 •cows Avere under complete herd control and vaccine and 19 herds totalling 2013 cows Avere under herd control and four herds totalling 37.) coays had single tests at irregular periods. During the season the 1 , resazurin test has been tried out on creams and in the shed on single cow composite samples for mastitis, For large numbers of creams I still' prefer the methylene blue modification but for a rapid platform test on a ieAV samples the resazurin has its advantages. The mastitis resazurin results were also good but in my opinion not as satisfactory as the microscopic test. It can be carried out in the shed but daylight is needed for sicetirate consistent results a comparator instrument Avould be necessary. For cheese milk supplies or town milk supplies the resazurin test is excellent. In England and Wales the test is officially recognised and made •compulsory by the British Ministry of Agriculture. The difficulty of obtaining the resazurin dye may account for the fact that the test is not yet made. compu)-> sory in this country. A A'isit to the Laboratory Avas paid by a Director of the Okitu Dairy Factory, Gisborne, and as avcll asbeing delighted at the efficiency of the factory he Avas so impressed by the. resazurin test that he asked 3'our Directors to allow me to A'isit the Okitu Factory and demonstrate the resazurin test and that they ■would Avi'.lingly pay all expenses. They have one of the latest pasteurising and milk bottling plants supply all the school milk lor a large, district and, possibly all the toAvn milk and turn out so good a product that from taste it is practically indistinguishable from raAv milk. They are very satisfied Avith the resazurin test and are now able to notify a supplier before his next

milking .should his milk not he up to standard. Sir Harry Battcrbee, British Trade Commissioner, was visiting the factory the day [ was there and he was also interested in seeing the test. A demonstration was also given to the Medical Officer of Health and the Hospital Bacteriologist and they Ave re impressed. AA 7 ith the saving of limr compared Avilh the' official methylene blue or reductase test. The Okitu Directors appreciated very much the action of your Directors in allowing me to visit, their factory. I am ])leased to report that in regard to mastitis we are co-operat-ing Avitli the Animal Research Station. Department of Agriculture, Wallaecvilte. Dr liopkirk Superintendent and the N.Z. Dairy Board represented by Mr Hume and his local officer, Mr Whitham. The following extract from the April Exporter may be of interest: "Mr Whitham was Avoiding in close touch A\ith the laboratory of the Rangitaiki Plains Dairy Co. which "prepared a vaccine for the eoiili pany's suppliers. If they Avanted to follow up the matter, they could do so there with conliclence, and Mr Hodson, who Avas in charge of the laboratory, Avas AvorUing with then (the Dairy Board) 100 per cent. Before a cow Avas vaccinated, Mr Whitham took a sample and got a leucocyte count, and similarly, samples Averc taken at two weekly intervals, so that, they could from time to time, get a picture of Avhat Avas happening. Mr liopkirk. Mr Hume and Mr Whitham visited the laboratory and also conferred with the Veterinary Committee, Mr Thomson and myself to arrange Avork for the coming season. At J)r liopkirk's suggestion 1 spent seA'cral days at WallaccA'ille Avith him and Ave jointly examined numbers of mastitis smears and Dr liopkirk is quite satisfied to accept any results from this laboratory. Il have since sent smears examined here to him and in the •maojjrity our results have been identical and in a small minority not more than one point difference. Your Veterinary Surgeon, Mr Thomson is in close touch Avith all that is proposed and 1 appreciate very much his past co-operation and look forward to his, assistance in the coming season. For some time the A'ariation in strength of the alkali solution used in the can washer has giA'cn mc concern but I am pleased to say that for several months an alteration is proA'ing satisfactory and reliable. A rcseiwoir of stock alkali solution holds enough for several days run and this feeds into an automatic (lush 2 gall cistern which can be

nd.justccl to discharge From 15 to 150 minute intervals into the can Avashct alkali compartment. Once atljustcd it is only a matter of opening a valve or closing a valve when the can 'washer is not working. Temperature ol' the solution is also important but this i.s automatically controlled on the can washer itself by a thermostat. In conclusion would like to express appreciation of the co-operation of Mr Kutherford and the different branches of the factory.