QUALITY OF MILK

Hawera Star, Volume L, 5 March 1931, Page 5

QUALITY OF MILK

VARIOUS AFFECTING FACTORS

ADDRESS BY AIR P. O. VEALE.

Factors affecting the quality of milk were interestingly dealt with by Mr P. O. Veale, dairy scientist at the Hawera Laboratory, in an address given bv invitation to a meeting of the Alton branch of the Farmers’ Union at Kakaramea last night. Mr H. Hodge (president) was m the chair and there was a good attendance of members. A cordial welcome was given bv the chairman. • Mr Veale said that in dealing with the subject of the quality of milk much depended on what was going to be done with the supply, because there were different aspects to be considered if it was to bo used for human consumption, for cheesemaking or for buttermaking. As in this district cheesemaking was most important, he said he would deal with the subject from that ooint of view and would consider the questions of dirt in the milk; flavours, from feed or from shed surroundings ; water in the milk, and !bacteria. He remarked that while milk to' be used, say, in a condensed milk factory must have only a very small acidity, for cheesemaking acidity was not harmful. Dealing with flavours, Mr Veale said that flavours resulting froni bacterial action wore vgtv unciGsirafolo ana would continue right through to the finished cheese, generally getting worse as the processes went on. Pasteurisation, he said, obviated _ some, but it was not capable of eliminating all. Some would remain and would work after the cheese was finished | making. It might kill the germs, but not the enzymes produced by bacteria. If the milk was originally dirty, cheese would be always inferior. He stressed the fact that pasteurisation did not clean bad milk, hut frequently made a temporarv improvement. It might enable the ‘cheese to pass the grader in New Zealand, but would show its bad results afterwards, and it was therefore essential that the right quality of milk must come to the factory before really good cheese could be made. Feed flavours, he said, due to wrong feeding or feeding at the wrong time, tended to dissipate, and this was helped by the aerating of the milk. He urged the need of feeding strong fodders as far as possible from milking time, that is, immediately after the usual times of milking. Flavours absorbed from bad sur- 1 roundings in cowsheds were to be carefully avoided, and to effect this sheds should be sanitary and well ventilated and manure should be kept away, for milk absorbed such flavours very readily. Bat, lie added, surroundings were "not everything, and while he would not minimise the desirability of good surroundings, it was what was in the milk that counted most. It was practically impossible to avoid all dirt, and it had been proved by experiment that dust in . average conditions contained comparatively few germs and did not affect quality. The great enemy of the cheesemaker was 'the virile germ, and that question Iliad to be treated in a commonsense way. Often a cowshed was not of the best, but the milker took more pains to get good milk, and the result was apparent. in the quality. “It is not so much the surroundings,” said Mr Veale, “but what you do in them that counts, and what the man in tlie factory does with the material provided by the milker. Good surroundings are desirable, in milking sheds and in factories, but they are not the only things that matter. And it is necessary to see the machines when being used in order to know where the trouble lay.” Water in milk, proceeded, the speaker, was to be carefully avoided, for it made the curd flabby and thus manufacturing losses were increased. He said lie had seen in milk evidences of water from pools or dirty creeks, and the germs of slimy milk often came from impure water.

PRESENCE OF GERMS. Mr Yeale dealt very interestingly with the subject of germs, which he considered a most important subject. They were, he said, always present in milk and increased very rapidly. All genns did not cause disease, but actually only a few out of the many thousands of varieties of germ known to

scientists. He instanced how an outbreak of typhoid had been traced not to the germ in the milk, -but to the milker, who was what is known as a “carrier.” . ‘ , Referring to pure milk, he said that there were very few samples, even the best, which contained less. than 10,000 to the cubic centimetre, that is, about half a teaspoonful, while the average milk supplied to ' a cheese factory would contain up to 500,000 to the same quantity. Tin an interesting way he explained liow the germs were estimated under the microscope. In this way they graded finest, first or second. And, he said, germs came from everywhere, from the water, or from the hands or the clothes of the milkers, because milk was ideal for the collection of germs. Dealing with their increase, he said that this could be realised fully when it was known that each germ would split up and double in 20 minutes and ~ each would then be ready to multiply again in a similar way. It was estimated that one germ at this rate could increase in 14 hours to about two million million. , . i In order, said All* Veale, to check this, cooling of milk was essential and ._ nothing was so effective. In many cases cans would be up to 70 degrees F., and it was absolutely necessary, if germs were to be kept under, that some cooling system should be used, the ideal being to keep the night’s milk to about 50 degrees F. Warm surroundings always caused trouble, and he strongly urged having the milk stand where it could get all the fresh, cool air possible and the milk divided into as many cans as could be and, if possible, immersed in water, for there was no more powerful aid to good quality milk than cool, clean surroundings. His message in this respect would be to take the greatest care to secure storage for the night’s milk as cool as was possible. Air Veale stressed the essential need of carefully and regularly sterilising buckets and cans, and added that this was even more important than the entry of a moderate amount of foreign “Surroundings,” concluded Air Veale, “are very desirable, but they are not the controlling factor and will not of themselves make good milk, hut it is what we do in those surroundings that counts most—the sterilising of cans and buckets with .boiling water, tilting them afterwards so that they get the sun into them and become perfectly dry, for tlien germs cannot multiply, and finally keeping the milk cool by some method and using as many cans as possible, giving the milk every opportunity to keep sweet and fresh by the cool wind and remembering that dust is as. nothing compared to°tlie multiplication of germs in the milk.” He urged everyone to have liis sheds as good as he could afford, and then he felt sure that, by care and cleanliness, he would get as good results as the men with expensive appointments. On the motion of Mr Tong, seconded bv Air L. Hunt, a hearty vote of thanks was passed by acclamation .to ’ Mr Veale for his interesting and in- , strnctive address.

The president also added _ his personal thanks, and Mr Yeale in acknowledging the appreciation said that it had been a pleasure to him to come down and address the members.