PASTEURISED MILK.

New Zealand Mail, Issue 1261, 30 April 1896, Page 6

PASTEURISED MILK.

Bulletin 44 of tho Wisconsin Experiment Station gives a complete statement of this matter. In brief, to “ Pasteurise" milk, it is heated to 1-lOdeg to 17adeg Fall., while to “ sterilise " it, tho heat is raised to 212d0g. Tho object of applying heat is to destroy tho bacteria which produce the changes called souring. At 212 deg Fall,, these bacteria aro destroyed —hence tho milk is “ sterile " or without life, so that it is said to have been sterilised and will keep sweet for some days —until new bacteria are introduced. The disadvantage of the sterilising is that tho milk has a scorched or “ boiled " taste that is disagreeable to many. There is also a change in the physical properties of milk. For example, rennet used in this heated milk gives quite a different result from that found in raw milk. When the miik is “ Pasteurised " or heated to something over MOdeg Fall., the active or living germs are destroyed, and if the milk is at once put in a cold place, where tho action of bacteria is slow, it will keep sweet for several days—longer than ordinary raw milk under similar conditions. Tho “Pasteurised" milk docs not have tho “ cooked “ taste which is found . in tho “ sterilised " product. The latter will keep swoot longer as. while a temperature of 140 deg destroys most of the active bacteria, others aro left which, in time, develop and bring about a curdled conditign, which is found to be different froia

that of ordinary sour milk. Tho wisest scientists now agree that the best milk of all is pure, raw milk with as little change as possible between the healthy cow and the consumer. It is pretty well proved that the bacteria can be kept out by mechanical appliances —without the application of heat.