"REDUCTASE" TEST FOR MILK.

Press, Volume LXI, Issue 18419, 27 June 1925, Page 3

"REDUCTASE" TEST FOR MILK.

(specially wstttex *ob "thb pszss.") (By A. A. Bickerton.) The "reductase" test is a special test prescribed under a Regulation of the Pure Food and Drugs Act, to prevent the sale of milk unfit for human food. A specific method is prescribed that has merely a legal value, because all that is required to make the test for one's health sake is that a drop or two of a solution of a dye, known as methylene blue, be added to a small sample, contained in a glass or tube, of the milk to be tested. So long as the sample remains blue it is safe to drink the milk, but if the blue colour changes to white it ceases to be so, although it uii.y. for some hours after, bo used for making puddings, etc., or if boiled.

Unlike litmus, methylene blue does not show that the milk is developing acid, and so Incoming merely sour: but it indicates the much more important fact that when the blue has changed to white the milk has lost all its free oxygen, which becomes used up by the living organisms which are known as "reductives." These organisms are so greedy tor oxygen that they extract all contained in the methylene blue salt and so_ makes it white, just as the red colour is taken from oxide of iron (rust) when it is changed back into iron. Animals live by breathing the oxygen in the air to burn their food, so producing warmth and vital energy. Plants cannot live on oxygen, but live on a gas breathed out by animals, via carbonic acid, and from this plants subtract the carbon, and return the purified oxygen to the air. Thus there are two great kingdoms, the animal, which forms from oxygon gaseous food for the vegetable kingdom, that again purifies tho air for the animals. Even when the organisms are so small thatfcome cannot be seen by powerful microscopes, this difference exists, and hence there are some micro-organ-isms -which live in the presenco of air (oxygen) and others that come after the oxygen has all been used by the former. These latter are 'dangerous to humans. In their milder forms they are the bacteria which produce tho putrefactive changes that give the bad smell to meat and rotten eggs, and this offensive smell is Nature's warning to us of danger. More deadly species of bacteria turn nitrogenous food into poisonous animal bases that are called "ptomines." These smelly safeguards do not appear in milk so timely, because the sugar in tho milk is turned into acid by air living microbes, and this acid prevents the smell becoming apparent until too late to be a safeguard. It is to this fact that the methylene blue test owes its supreme importance. It proves when the oxygen has left the milk and putrefactive changes, or greater dangers, have set in. .

The milk-man who has recourse to I the "cow with the iron tail" and j therewith adds pure witter to milk, ! does no harm, to the health of his cus- j tomers, and shoula the liquid not prove sufficiently nourishing, well you can increase your supply. The milkman merely becomes a thief. If fat is subtracted from tFe milk, it is more serious, especially for irfanta or invalids, because the ratio of fat to proteids and carbohydrates is altered, and diseases due to mal-nutrition may occur. But the man who distributed milk which gives a bad reductase test may be a potential murderer; for no mothers milk that I have tested gave a white test, not even after the milk had become so old that the curt and serum separated. This was also the case with some > cow's milk that had not become infecte'd with "reductase." So under healthy, natural feeding infants and calves get. pure sterile milk.' Therefore it is dangerous to feed an infant on milk giving a white reductase test. With regard to adults, who are not so dependent on milk alone for food, the case may not bo so serious. But it is bad enough, and the reductase test is the only safeguard from many diseases, and also the dangerous food poisoning group of bacteria in milk. Boiling or pasteurising is not sufficient, for milk may become infected after, as actually occurred in a recent local case when a small jug of boiled milk, left overnight, poisoned a milkman and his family—several fatally. What might have happened if he had poured the infected milk into that supplied to his customers I will leave to your imagination, and also the havoc that could bo inflicted upon a community should powerful milk cooperations continue to succeed in legally evading the law, by such refined academic excuses as those which have been recently made to escape punishment for selling bad milk. They risk causing a whole town to be infected with the microbes that lately poisoned the milkman and family, and in the past devastated a French army. When it is considered that the recent epidemic of "infantiio paralysis" was duo to a bacillus that followed in the pathway of our milk supplies, it makes one thoughtful. The legally prescribed "reductase" test is not harsh or unfair, but a common sense .practical test that detects milk already legally unfit for sale. For good fresh milk mil not give a white test for at least 24 hours' at a temperature about lOOdeg. F. And milk kept cool and clean will comply with the required three hours' test even after 24 hours; therefore, if the legal test .be applied before 6 o'clock in the evening of ' the day from which the milk from the cow,' it will not give a white test unless the milk is either very dirty, mixed with stale milk, not properly cooled, or *,aken finom a diseased cow, and the sale of milk under these conditions is illegal without the test.