Raw Milk Spells Danger

New Zealand Listener, Volume 37, Issue 951, 1 November 1957, Page 18

Raw Milk Spells Danger

(GUINEA-PIGS, as you know, make | quite good pets for children. They are also invaluable in medicine, They ere the little animals used in many laboratory procedures that diagnose your illnesses and safeguard your health. It is of this latter benefit, in one of its aspects, that I am dealing. Did you know that guinea-pigs are used to test the safety of raw milk as regards tuberculosis germs? Well, they are. Health inspectors are continually sampling milx sold in towns all over New Zea-iav-i, both pasteurised and raw. A proportion of the raw milk samples are sent for the ultimate test for safety from infection with tuberculosis germs, the guinea-pig test. In one of our big cities, in May, 1956, in 82 raw milk samples so tested, one zave a positive guinea-pig test. That raw milk contained tuberculosis germs in their thousands. In the same _ big city, by May, 1957, the dangerous situation of even one raw milk round infected with tuberculosis (because that is what a positive sample means) had changed to nine positive ginea-pig tests in 45 samples taken. What a lot of people in that city were being subjected to the risk of contracting tuberculosis! Please remember that they want to take this risk, because they believe in raw milk, and will not have the pasteurised and safe milk available in the same city. I suppose it is all.right for the adult to have this freedom, this "right," to infect his own body, but I often wonder whether it is correct to put children to this risk when they have neither the understanding nor freedom.to judge for themselves, A father or mother who persists in taking raw milk can never be sure the children will not pick up tuberculosis germs, It is no good depending on tuberculin testing of herds, In that big city the ginea-pig tests showed that herd testing was not enough, for those: herds supplying town milk were tuberculin-tested. Between tests cows can break down, or a new infected cow may be introduced to the herd, For safety with milk you need herd testing, certainly, but backed up with pasteurisation as -the final and surer safeguard. This tuberculosis risk is not the whole story. Going back to that big city, those raw milks in May, 1956, in 82 samples, showed 44 carrying the germs of undulant fever. In May 1957, another 45 samples proved positive 22 times for brucellus abortus, the germ of undulant fever. That works out at just about every second sample carrying the risk of undulant fever. As you know, contagious abortion is common in our dairy herds; this milk samplirtig picture proves the point, and brings the amount of risk out into the open. This undulant fever is a nasty disease, of recurrent bouts of high fever, very debilitating, and often persisting for months. In this country of ours we have not yet had a year free from disease conveyed by raw milk. It is quite beyond me why people go on demanding it. Remember, there are other risks than these ever present ones from tuberculosis and undulant fever: Risks from septic germs from fingers or noses and throats of milkers and those handling or bottling raw milk, risks from typhoid fever, dysentery, and food poisoning. All these have been conveyed by raw milk in New Zealand. You can depend on pasteurisation to make milk safe from all these risks. You say, what about the human factor?

How do we know that milk is properly pasteurised? Those same health inspectors who sample raw milk are also constantly supervising the correctness of pasteurisation, and taking samples of pasteurised milk from treatment houses and from roundsmen. These samples are subjected to several types of tests, a chemical one, a bacteriological one, and occasionally to the guinea-pig test.-This latter is not often done because, if the chemical or phosphatase test and the bacteriological or reductase test are satisfactory, it is impossible for harmful germs to have survived the heat treatment of pasteurisation. The phosphatase’ test is always carried out. If satisfactory, it is evidence that the milk has been heated sufficiently. to kill all harmful germs. The test depends on the fact that the enzyme phosphatase present in raw milk is destroyed by heat. Milk properly pasteurised will therefore contain no phosphatase. So a chemical test is used to determine the presence or absence of this phosphatase, and the analyst sends a report to the Medical Officer of Health accordingly, that the pasteurisation has been properly or improperly done. The accuracy of the process of pasteurisation is well checked. The risk of infection is ever present in raw milk. Go for pasteurised milk and safety!