OUR BABIES.
1 [BT Hyoeia.]
Published under the auspices of the Society for the Health of Women and Children. "It ia wiser to put up a fence at the top of a. precipice than to maintain an ambulance at tho bottom." DR. CHAMPTALOUP'S LECTURE. (Concluded.) How Bacteria Are Counted, Tho method of counting tho bacteria may be of interest. An. accurato quantity—generally a cubic centimetre—of the milk is mixed with varying quantities of sterile water, so that it is highly diluted in definite proportions. A cubic centimetre of each of these dilutions is now added to liquefied culture medium, thoroughly mixed, and the whole poured into O'io of tho glass capsules called tietri dishes. When the medium has set, the senes of dishes is put in the incubator ior 43 hours, and then examined with a hand magnifying ninss. Each bactcrium present in the criminal dilution of the milk will now have multiplied to such an extent as to have formed a visible growth. The number of thc-.se visible growths, or colonies, as they are called, is then counted, mid by a process of multiplication the number of bacteria per cubic centimetre in the milk sample is found. A cubic centimetre represents about a third of an ordinary thimbleful. In this way the number of bacteria in the city water supply was couuted, and the average of a series gave 350 bacteria per cubic centimetre, though this varies considerably at different periods of tho year. Then some of the same water was filtered through an ordinary charcoal filter, and there was a considerable reduction in the number of bacteria present. Samples of Milk. Next, the following series of milk samples was examined:—No. 1 sample of milk may be taken as tho ordinary milk supply as delivered. The number of living bacteria per cubic centimetre was 32,000. Next, a sample of humanised and pasteurised milk, freshly prepared, which gave only 2700 living bacteria per cubic centimetre. Note the very great improvement as a result of pasteurisation. Next, samples A, B, C, and D from cows milked under varying conditions, and tho examinations made almost immediately. Sample A was m'ilked with every possible precaution against contamination, nnd_ the low count of 50 organisms per cubic centimetro was recorded. Sample B was milked under similar, though less rigid, precautions, and the count was 4000 per cubic centimetre. Sample C was milked with ordinary care, such as tho washing, of the cow's udder, milkman's hands, and tho rinsing out of tho bucket with hot water. Sucii conditions should be, at least, an. absolute requirement of nil dairymen. Tho count iu this ease mounted up to 10,800 per cubic centimetre. Samplo I) was milked, as probably too many cows are milked, with no special care with regard to cleanliness, with a resulting count of 57,000 per cubic centimetre.
The difference between the four samples is remarkable, and spealts volumes m favour of clean milking, and yet, as milk goes, none of these was. a very had sample. Twenty-seven samples of milk as supplied from door to door were then examined, and the average count found to bo 10,700 organisms per cubic,centimetre. Similar experiments in a large American city gave an average of 11,270,000 per cubic centimetre, so that Dutiedin milk, at the time of examination, compares more than favourably with Hint city's simply. ■ '
Eosenau, in a recent book on milk sunplies, states that certified milk should never exceed 10,000 bacteria per cubic centimetre,' and that health officials should endeavour to keep the general supply below 100,000 bacteria per cubic centimetre.
Influence of Varying Tempetntnres on the Rate of Growth of tho Bacteria in Milk.
Finally, at Dr. King's suggestion, tho milk samples 1 and 2, and A. B, C, and D were examined, to ascertain the influence of varying temperatures on the rate of multiplication of the bacteria originally present, and a glance at tho accompanying table will show that samples left at room temperature for the day gove counts showing considerable increase in bacteria, but more or less in proportion to the originnl contamination. Those samples kept on ice showed a slight increase only, while those at llodcg. ]?. shoTiad 'many millions, and the milk curdled in 12 hours. Others kept at 120dcg. F. only doubled their original count—an important feature, as in hot tropical countries where ice cannot be obtained melk could easily lie kept at this temperature, or a little higher, and remain in much the samo condition as when milked. The temperature is evidently too high' for the liking of tho bacteria. Samples kept at 130dcg. F. were practically sterile after 12 hours, so that ibis temperature is evidently more efficacious than the higher temperature of 14ft, when applied for a shorter period. Experiments are now 'boring carried out with temperatures between 120deg. and 130dcg. F., to ascertain just that temperature which will have the fame effect on the bacteriological condition of the milk as if it had keen kept on ice. lIILK SAMPLES. . ~ § 3S g It, .§ .■■§£ 0 5 'So'i o„ . « , S-J > Sr.S tih Ditto DittoNj Sample. £g•< s at at | * 05J 8 O § 0 o 115 F 120 Fj J o oSH o^H a z a I 0 No. 1 many Houbo 32.0001,000,000 34.000 mil- 50,000 .3 Delivery. lions. No, 2 Huinanl'cd 2.700 1,300 3,100 ... 4,000 0 rantcnrl'ea No. A, 5n wi Every precaution From Cow- taken Ditto' 11.SD0 Very caroful milking No. C- IO.SCOi 47 000 Careful and cleanly Ditto. ' | ' milkinG No D. 57,000j 94,500 Ordinary method Ditto, | millting In conclusion, Br. Chainpmen said:—"l have endeavoured to tell and show you I something of those wonderful little plants wo call bacteria, and the experiments we have made with milk prove that with ordinary cleanliness and caro we can secure our food supplies, more particularly milk', meat, and fish, in a state of comparative purity. "What I want you to consider is this: Is it not worth while paying a little more for milk which our dairyman can certify as produced under the most cleanly conditions, and from cows certified ns free from disease? Or, is it not worth patronising the tradesman who screens his shop from flies and dust, and serves our meat, fish, or fruit in a .cleanly manner? At the recent Tuberculosis Conference in Wellington wo passed a resolution recommending ns an initial stop that hospital boards should lead tho way by requiring that their milk supplies should bo certified—a recommondation which, I am glad to say, tho Otago Hospital Board havo wisely adopted.
Permanent link to this item
Hononga pūmau ki tēnei tūemi
https://paperspast.natlib.govt.nz/newspapers/DOM19130531.2.106
Bibliographic details
Ngā taipitopito pukapuka
Dominion, Volume 6, Issue 1764, 31 May 1913, Page 11
Word count
Tapeke kupu
1,086OUR BABIES. Dominion, Volume 6, Issue 1764, 31 May 1913, Page 11
Using this item
Te whakamahi i tēnei tūemi
Stuff Ltd is the copyright owner for the Dominion. You can reproduce in-copyright material from this newspaper for non-commercial use under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International licence (CC BY-NC-SA 4.0). This newspaper is not available for commercial use without the consent of Stuff Ltd. For advice on reproduction of out-of-copyright material from this newspaper, please refer to the Copyright guide.