EXPERIMENTS ON MILK.

Dominion, Volume 1, Issue 231, 23 June 1908, Page 3

EXPERIMENTS ON MILK.

A NEW PRESERVATIVE DfSGOVERED. INTERESTING. RESULTS' REPORTED.'. In a recent" paper before • 'the MedicoChirurgicalSocioty at Edinburgh Dr. Robertson suggested that instead, of: making it a penal offence'to add preservatives to millc it would be advisable that the authorities should allow the addition of the minimal amounts of harmless antiseptics to milk, Mjguing -.that'it would -be; better : to run' the slight risks' of their injurious' action (if;' indeed, they had. any) rather than the undoubted risks'which result from the use of suoh ;a putrescent 'fluid as ordinary dirty milk. He'did not share' the belief that antiseptics., such' as boric acid or formaldehyde, if used in minimal amounts, exerted any deleterious action, on'the animal economy. Happily, however, another agent had been'applied to the -purification and preservation of. milk.. This was nasoent oxygen as evolved from: peroxide of hydrogen' in contact with milk at a suitable-and optimumtemperaturo. It would be difficult to raise objections ,to an. agent so easily decomposed into harmless components." ' The addition'of of hydrogen had been worked out scientifically as well as practically by Dr. Budde, of Copenhagen. ■ •

Remove tho Dirt Particles. Dr. Buddo had advocated the romoval by machinery of dirt particles from milk before, pasteurisation.. This machine not only removed all particles of dirt in a . far 'moro effective way than'a filter, but it also removed many/ bacteria adhering to the particles of dirt -and to the minute motes of the tissues of tho cow- which were always present in milk. '■ The 'bacilli thus adhering to dif-' foront particles had been experimentally proved to bo tho most resistant, which fact seemed to bo a mere question of mechanical protection, It was very likely that, for instance, natural tuberculous milk in which disintegrated udder-tissub was abundant was far more difficult to sterilise than milk to which cultures of bacillus tuberculosis had been added. It was a well-known fact that tho natural tuberculous milk could not even bo satisfactorily sterilised by boiling. Dr. Buddo. therefore considered the centrifugal macliino to bo a vory important part of any milk treatment. v Tho New preservative. After the milk had passed through themachine it should bo mixed with a -little peroxido of hydrogen; That 1 , in small quantities, was a. .perfectly harmless substance. Every living cell contained' an enzyme (or catalasc), whoso characteristic quality was its power to decompose hydrogen peroxido into water- ' and oxygen, and its ' presence everywhere oxcluded the possibility of hydrogen peroxide-ever being found in a living cell. Consequently hydrogen peroxide in contradistinction to all other antiseptics, could not be absorbed by tho organism, but was invariably, decomposed before it got through the walls of. the intestinal canal. The harmlessness of (hydrogen peroxide taken by tho mouth had also been established by numberless experiments..

Striking Flsuros. » 4 , The milk also contained a certain amount of catalasc—sometbir- like 0.000001 pcr'ccnt. When hydrogen peroxide was added to milk at about SOdeg. C/(l22deg. F.) it was ablo to decompose about. 0.035 ■ per cent. H202. The hydrogeri_ peroxido possessed in itself a strong germicidal power, according to' Valdemar Bie, so" strong that 1000 bacteria could be destroyed by,O.OCOOOOOOS4 gramme H202. But, the milk catalasc caused a still stronger bactericidal action to take place which arose from tho 1 formation of oxygon 'in statu nascendi (monoatomic oxygen), and which Dr. Budde had named the secondary germicidal action:_of. hydrogen: peroxide. Ho proved the existence of this secondary effect by comparing the action of hydrogen peroxide with that of other disinfectant, , arid thereby found"that all other antiseptics kept the milk'fresh for a longer time at ordinary than at a slightly elevated temperature, wheress the revorso was the case with hydrogen peroxide.

Singular Properties. He proposed to heat the milk to 50dcg. ,C. (122deg. F.) because ho found that this temperature was the optimum for tho secondary effect, and it was not. high enough to alter tho qualities of the mill;. The milk was kept at the same temperature for threo

hours,' after which it was filled through storilised tubes into sterilised bottles, aud instantaneously cooled. Dr. Budde said that H202 had the great advantage, that (according to Sicber and Loowcnsteinj it destroyed toxins, but loft antitoxins-quite unaffected. In, for instance, a neutral mixture of diphtheria toxin and antitoxin, the latter might be set free by the addition of hydrogen peroxide. Advantages. Milk, after having been subjected to the foregoing treatment, possessed the following qualities. Nono of the component parts of raw milk were in any way altered. The milk was practically sterile, and most especially so in regard to the specific paithogenio micro-organisms. The milk was able to be kept considerably longer than ordinary milk, but, notwithstanding this fact, it should, of .course, like all milk, bo consumed as fresh as possible.- • The milk was absolutely free from foreign substances. The milk onzymes .wore unimpaired. Tho oxydases wore destroyed, but, seeing that these did not occur in human milk, this was genorally considered of no importance. The catalaso was destroyed. On the other hand, oxydases nearly always accompanied catalaso, so that by the final addition of a little catalase both those classes of enzymes wore restored to the milk. The nutritive qualities were unaltered, and numerous cases had beou recorded by- medical men in which people (both infants' and grown-up people)'had been doing very badly on raw or cooked (pasteurised and sterilised) milk, whereas milk thus treated had agreed very woU with theni. . The tasto and flavour of the milk were practically unaltered. ' Tubercle Cerms .Killed. . Further special experiments on natural tuberculous milk had been conducted by. leading scientific men, who declared unanimously that non-sporing organisms and the vegetative forms of sporogone bacilli were killed by tho process. Regarding the spores there was somo difference'of opinion, which could in most, if not in all, cases be traced back to some defect in . the method used. He was confident that tho method in its present shape killed even spores with cortainty. Any bad influence of tho treated milk had never been observed, but it had often been found to bo bettor and moro easily absorbed than ordinary milk. The treated" milk seemed to bo_ of thorapautio value in the case of certain diseases, as, for instance, typhoid fever, achylia gastrica, etc.