DAIKY FARMING— DAIRYING. 275 



r(1.4rt and 'X',.U'>. rospcftivoly, for the 2 lots, in furthor oxporimonts cold storage 

 gave bottt'r results than tJR' ordinary t-uring room for both parattlned and nn- 

 paraffinod <'lu'osc\ It was estimated that paraffining cheese effected a savini; of 

 22.5 cts. pel- hundred when cheese was cured from 00 to 100 days at ordinary 

 temperature. 



The P>ai)cock test was compared with chemical analysis of 15 samples of 

 skinuned milk, the test being made with alxmt one-fourth more acid than usual 

 and the tester run at a higher speed and several minutes longer than custom- 

 ary. The average results for the 2 metlKjds were, respectively, 0.1 and 0.1t)S. 

 In tests Willi 4 m.akes of hand separators, dilfereni temperatures of milk and 

 variations in speed of separator bowl were conip.-ired. With cold milk and low 

 .speed, 0.44 per cent of fat was left in the skim milk as determined by tlie Bab- 

 cock test. 



"The most satisf.-ictory slcinnning was secured when tlie milk had a temjx'ra- 

 ture of about S5° F. and the separator operated according to the directions of 

 the manufacturers." 



On the detection of a tainted condition in pasteurized milk, H, L. Kusseli. 

 and ('. lIoFFMAXA' (Wisconsin Sla. h'/il. 11)0.'). pi>. 2.iJ-2.ii!). — The station was 

 called upon to investigate the cause of an undesirable flavor in the product of a 

 large dairy company which was pasteurizing its milk for the general city trade. 

 The investigation showed that the trouble was due to the custom of passing 

 steam through the pasteurizing machine immediately before the milk was turned 

 into the apparatus. Some of the steam condensed in the machine and this not 

 infrequently contained enough grease or oil to impart an objectionable flavor to 

 the milk. The case is considered interesting as indicating how much trouble can 

 sometinu>s ])e caused ])y an apparently trivial circmustancc. 



Studies on pasteurization of milk in a " continuous-flow " machine (Miller 

 apparatus), II. L. Kussei.l and C. Hoffmann (Wisconsin Sta. Rpt. 1905, pp. 

 232-2 '/I. /![/. 1). — In deternuning the period of exposure, use was made of the 

 following method, which is believed to have superior advantages over the 

 colorimetric method ordinarily employed : 



" The heater is first filled with water. To determine then the mininmm 

 period of time necessary for any particle of milk to pass through the machine, 

 the exact time of starting the milk flow is noted, and also the appearance of 

 the first indications of turbidity. This gives the time necessary for the most 

 rapidl.v flowing particles of milk to pass through the machine. To find the maxi- 

 mum ])eriod of exposure, some samples of the milk are taken at the cmtlet at 

 stated intervals, every 5 or 10 seconds or so, for a period of several nunutes. 

 A determination of the fat in these samples is then made. 



" When the fat content has been restored to its original amount, it indicates 

 that all of the water in the machine has been replaced by the flowing milk. 

 By charting these fat determinations, not only can the miniuuim and maximum 

 periods of exposure be ascertained with exactness, but the actual exposure for 

 any proportion of the entire flow can also be found." 



With the iiiacliiiie umhT investigation the results of tests showed that some 

 of the milk i»assed through in 15 sec(mds and some in 45 seconds, but that most 

 of the milk remained in the machine alwut 'M) seconds. When the rate of flow 

 was diminished about one-half, the minimum periotl of exposure was from 25 

 to 2S seconds ;ind the maxinuun from 70 to lOO seconds. 



Bacteriological examinations were made of the raw milk and the milk after 

 heating, after cooling with water, and after cooling with ice water. The rate 

 of flow approxinuited 1,800 lbs. per hour and the rate of exposure ranged from 

 15 to 50 seconds. I<"'rom the results of te.sts made under both winter and sum- 

 mer conditions it is considered apparent that the luunber of bacteria capaitlo 



