Bacteria Danger in Dairy Factories

Sun (Auckland), Volume 1, Issue 81, 27 June 1927, Page 12

Bacteria Danger in Dairy Factories

SCIENTIST EXPLAINS LECTURE AT ROTORUA ( Special to THE SUN.) ROTORUA, Friday. A LECTURE of particular inter'4r*' est to dairymen and dairy factory managements was given to the National Dairy Association bv Mr. P. O. Veale, 8.A.. M.Scf, scientist to the Federated Taranaki Dairy Companies, at Rotorua on Thursday. Mr. Veal© said that rather too much attention had been paid in the past to the quantity production instead'of to the quality factor. This was the aspect that had been brought forward during the past year, and required efficiency. Efficiency nowadays was largely a matter of detail. In few factories could glaring cases of inefficiency be immediately found, hut there were many cases where many details tended to produce a considerable degree of inefficiency. CLEANLINESS ESSENTIAL To start right at the beginning the great necessity was cleanliness in the supplier’s milking shed. Thorough cleaning before applying the machine cups was an essential. Milk in the cow was invariably free from bacteria, except a few very harmless ones, and most of the troubles arose over uncleaned animals. Non.-acid milk and slimy milk were both caused externally, usually through .swnmpv ground. In his experience, milk cans were invariably clean, but they were very seldom sterile. Washing was usually by hot water and soda, followed by rinsing. This did not clean the cans properly, and any harmful bacteria remained. Cans should after rinsing be scalded with boiling water or over steam until the cans were too hot to touch. The cans should then be placed in a sloping position, mouth down in a position to allow draining and cleaning by wind. This was important, ns it provided the most difficult conditions under which bacteria could reproduce. All bacteria required dampness to thrive and reproduce. Cans

should not be stood upright under any circumstances when not in use.

In one case he had proved conclusively that the bacteria causing nonacid milk had been brought in by one supplier, gone into the common whev tank, and gradually infected every can used at the factory. The epidemic had been minimised by the suppliers taking concerted action. The rate of contamination was tremendous. The initial contamination might be very small, but in 24 hours even one bacterium could produce many millions. Under favourable conditions bacteria counted initially in thousands could in 24 hours become thousand of millions. This brought forward the necessity for cooling. Reproduction of bacteria was greatest at about 200 degrees, while it was still fairly high at 70 degrees. The best temperature was below 50 degrees, and the ideal 32 degrees. METHODS COMPARED Cooling had lately seen a considerable change over to the Schute method of cooling by air. This had a number of things against it, including the amount of contamination due to more surfaces, defects in the schutes, etc. In fact, he thought the system’s disadvantages far outweighed the advantages. The best idea was to put the milk straight into the cans, put the lids on, and immerse the cans in running water. When this was done all over the country finest grades would be the rule and seldom the exception. In these remarks he was referring particularly to milk for cheese. A great deal of the milk used for cheese-making would be condemned for drinking purposes. Mr. Veale described the colour a.nd microscopic tests, the latter of whicri he considered would probably become the general practice if milk grading was introduced as suggested. The grading of milk might take longer, but it could be done very quickly if re " quired. In -his opinion the testing should be done by the manager, ana in this connection the speaker made a plea to the directors to improve tne status of the managers.. Too many OI them were merely foremen workers. They should be free to do their 7?®*® properly, and should be given fasiliti^ s for making experiments. The technical knowledge could easily be gainea. and should be taught at the Agricultural College. Intelligent with scientific facilities invariably rewarded the factory. s . . „ He thought that the Hairy Division would welcome and assist any . ™ oV _j ment in the way of grading nnlk anu increasing the quality. , Wherever possible the farmer wo help himself and the factory by ca ing whey in special cans, and noi. the cans used for milk.