PASTEURISATION EXPERIMENT.

New Zealand Times, Volume LXXI, Issue 4407, 13 July 1901, Page 3 (Supplement)

PASTEURISATION EXPERIMENT.

An interesting experiment was carried out last year at the Ontario, Agricultural.. College with the object of testing the influence exorcised by the pasteurisation of milk and cream upon the butter obtained therefrom. The milk experimented with was thoroughly mixed in a vat, one half, of which was run through a pasteuriser, while the other half was run through a separator in the ordinary course. TM temperature for pasteurising ranged from 155 deg. to 162 deg„ while that for separation was 95deg to lOOdeg. The total quantity o< milk dealt with was over 5200 gallons, and the average percentage of fat in it worked] out to 3.5. After being Separated it was found that the skim milk from the milld that had been pasteurised contained .01) per cent, of butter fat, whereas the skimj milk in the case of that which had noti been pasteurised contained .1 per cent, of , butter fat. or two and a. half times more than the pasteurised milk. Notwithstanding the larger quantity of butter rat left in the unpasceurited unlit,, there was ootainea irom the latter a total] ol adjoin of cream', as against the 3,11»iil of cream produced by the same quantity! of pasteurised miiJt. Tne cream obtained from both sources was next analysed, ahq it, was found that that from tne pasteuris-; ed milk contained 27.3 per cent, of fat, whereas that from the raw or unpasteurJ ised milk contained only 25.0 per cent, of fat. Nor did the comparison end here,' Careful note was made of the churning results in both cases, and it waß found) that on an average every 10001 b of pasteurised milk gave 39.71 b of butter, while the unpastdurised milk.gave 40.21 b of butter. With the object of testing the quality and 1 keeping properties of the butter obtained! from the two portions of milk thus sc paw ately treated, samples were sent to two leading firms of butter merchants, who, without 'knowing the conditions unde* which they had been produced, kept them! for one. two. and three months respectively, and then judged them according to tho usual market standard. As a result of this test, the three 'boxes of pasteurised' butter averaged 42 points in flavour, and 23.6 points in grain, while that obtained from the nnpasteurised milk scored 43.8 points for flavour, and 24 points for grain. Special samples were then Bet apart fof the purpose of testing keeping quality, am| alter a month’s ‘Storage both were agai* judged. Tsis time the “pasteurised butter scored 39.3 points for flavour and 24 points for grain, while, the scoring in tho case of -the unpasteurised butter was 38.<j E oints for flavour and 24 for grain. After' eing kept for three months the pasteurised butter scored 38.5 points lor flavour and 24.3 points for grain, whereas the unpasteurised butter scored,only 35.5 point* for flavour and 24.5 points for grain, thu* showing that the pasteurised samples scored distinctly in keeping quality. The general conclusions drawn from th* experiments were ‘as follows;—(1) Then) was less loss of fat in the skim milk from! pasteurising the whole before separating.': (2) A smaller volume of cream was obtained from pasteurised milk, but the cream waa richer. (3) By using a starter before cooling there was no difficulty imripening tho cream from pasteurised milk. (4) Tbs pasteurised cream churned in‘less time than the raw cream. (5) The yield of butter "per 10001 b of milk was greater from the unpasteurised milk. (6) There was not much difference in the quality of the butter when first made, but when kept for a time the pasteurised butter possessed batter flavour. The net outcome of the experiment is ’thus summarised by the expert having charge of the investigations: —All the trials indicate that the pasteurised milk .butter had better keeping qualities. -thorigh when first made there waslittle or no difference in the quality. The chief advantage in pasteurisation is in making butter for the export trade or for storing, “and also in winter, when feed and other bad flavours .give the butter-maker trouble.