bluuebunny/crossref_metadata_2025 huggingface dataset:
147. The soluble protein fraction of milk
Authors: Rowland Samuel J.
Published: June 2009

1. The literature on the soluble protein fraction of milk has been reviewed to show the difficulties that are encountered in attempting to decide whether the fraction consists, as is usually supposed, of lactalbumin and lactoglobulin only, or whether it consists partly of secondary proteins of a proteose-peptone nature.

2. It has been shown that on boiling the casein-free filtrate of milk, maximum coagulation of albumin and globulin occurs at a pH. of 4–75–4–80. At this pS. prolonged boiling does not cause hydrolysis, and the amount of albumin and globulin N coagulated represents about 70 per cent of the total soluble protein N of milk.

3.By precipitation of the casein-free nitrate of milk with various con- centrations of trichloracetic acid, a partition of the soluble proteins has been effected which strongly suggests the presence of proteose-peptone substances to an extent in agreement with the results of heat coagulation.

4. The maximum amount of albumin and globulin rendered coagulable by heating milk itself has been determined by precipitating denatured albumin and globulin along with casein at pH. 4–7. This maximum represented an average of 76 per cent of the total soluble protein N in a series of normal milk samples, and reasons have been given for considering this maximum as the total of true albumin and globulin present.

5. The conclusion has been reached that the soluble protein fraction of normal fresh milk is composed of approximately 76 per cent albumin and globulin, and 24 per cent proteose-peptone substances.
175. The precipitation of the proteins in milk. I. Casein. II. Total proteins. III. Globulin. IV. Albumin and Proteose-peptone
Authors: Rowland Samuel J.
Published: June 2009

Improved methods have been evolved for the separation of the total protein, casein, albumin, globulin, and proteose-peptone substances of milk.

I. The use of acetic acid-sodium acetate solutions for the precipitation of casein is elucidated, and it is shown that the maximum precipitation of casein is rapidly effected from milk samples of varying casein content by the addition to 10 ml. of milk of about 80 ml. of water at 40° C. and 1·0 ml. of 10% acetic acid solution, followed, after 10 min., by 1·0 ml. ofNsodium acetate solution.

This maximum precipitation was found to be 1·0–1·4% greater than by Moir's method, and 2·4–3·8% greater than by the method of the Association of Oflicial Agricultural Chemists.

A procedure is suggested for the determination of casein which avoids the tedious transfer and washing of the precipitate, and gives enhanced ease, accuracy and speed of working.

II. The advantages of trichloroacetic acid for the precipitation of proteins in determinations of the total protein and the non-protein nitrogenous substances of milk are discussed.

The trichloroacetic acid methods at present in use are shown not to give complete precipitation, and for this a rapid method employing, at room temperature, a final concentration of 12% acid in the milk-acid mixture is recommended.

III. An accurate method for the precipitation of globulin uncontaminated with either albumin or casein is described.

IV. Methods are given for the precipitation and separation of the albumin and proteose-peptone substances.
184. The milk of the goat under English conditions
Authors: Knowles Frank , Watkin J. E.
Published: June 2009

An account has been given of observations made for over two years on the composition of the milk of the breeds of goat distributed throughout Great Britain. The average percentages of fat and solids-not-fat in the milk of the breeds, together with their standard errors, are recorded. The frequency with which evening and morning samples fell within specified limits of these constituents is indicated for each breed, and diagrammatically for all goats. Detailed analyses of the milk of each breed are given, with the maximum and minimum values encountered and the standard errors of the average figures. Comparison is made of the composition of the milk of the goat with that of the cow. The effect of stage of lactation on yield of milk and on percentages of fat and solids-not-fat are shown by means of curves. the effect of age on the yield and composition of milk is indicated. The average yields per lactation for each breed, based upon the records of animals officially recorded during the last ten years are noted.
211. Studies in mastitis. III. Mastitis in relation to “udder counts”
Authors: McClemont J. , Davis J. G.
Published: June 2009

By the term “udder count” in this series of papers is understood the colony count obtained when samples of early mid-milk (taken after about ½ pint has been removed from each quarter) are plated in milk agar and incubated for 2 days at 37°C. Dairy bacteriologists have long recognized the fact that cows with udder disease give high-count milk. In fact, some of those engaged in control work have made a practice of advising producers to search for mastitis when, in the absence of other causes, unusually high counts have been obtained in a series of samples. Therefore in low-count milk, at least, the milk agar plate gives some idea of infection in herds. The early observations, however, were not as a rule confirmed by satisfactory evidence of mastitis, i.e. by plating on blood agar or by cultural or serological typing of colonies picked off plates. This criticism also applies to many papers and statements in articles on mastitis as it affects other aspects of the dairy industry, e.g. off-taints, “slow starter” in cheese-making, and butter-making generally. Unless satisfactory evidence of mastitis is produced such work is valueless. Conclusions based on the results of the indirect tests are unreliable.
216. The effect of churning on the vitamin A and carotene content of milk fat
Authors: Henry K. M. , Kon S. K. , Gillam A. E. , White P.
Published: June 2009

The vitamin A and carotene content of 14 samples of butter fat churned from milk in the usual way has been compared in spectrophotometric and Lovibond tintometer tests with figures similarly obtained for the ether-extracted fat from the same milks. On the assumption that there is no loss of either carotene or vitamin A in the course of the ether extraction, it has been found that some carotene is lost in churning but that vitamin A is not appreciably affected.
224. The decomposition of citric acid by Betacoccus cremoris
Authors: Van Beynum J. , Pette J. W.
Published: June 2009

The fermentation products of Betacoccus cremoris in neutral milk are acetic acid and carbonic acid. In acidified milk or in mixed cultures of this bacterium and lactic acid streptococci the products are acetic acid, C02, diacetyl, acetylmethyl carbinol and 2–3 butylene glycol. The latter three substances may be called “C4 compounds”. Diacetyl is only formed when an oxidation with atmospheric oxygen can take place. Carbinol is found in aerobic and in anaerobic cultures. It may be reduced to butylene glycol. This reduction is more complete at lower acidity, but also depends on the strain of Betacoccus used.

All these substances are formed from the citric acid of the milk. However, small amounts of acetic acid may be produced from sugar.

From 1 mol. of citric acid are formed: 2 mol. of carbon dioxide, 1–1·5 mol. of acetic acid, 0·5–0 mol. of C4 compounds.

A reciprocal relation exists between the quantities of acetic acid and C4 compounds. When the amount of acetic acid is high the C4 compounds content is low. The higher the acidity of the medium in which the betacocci are cultivated the higher is the amount of C4 compounds. This means that the fermentation in neutral media is the extreme case of the fermentation process. Then the production of C4 compounds is minimal (0) and that of acetic acid is maximal (1·5).
276. The drying of cheese whey and of acid casein whey by the roller process
Authors: Waite R.
Published: June 2009

1. Experiments have been carried out in order to determine the best method of neutralizing cheese whey prior to drying by the roller process. The use of sodium or potassium compounds leads to difficulties in drying and the production of an unpalatable product of poor quality. Neutralization with calcium hydroxide gives a satisfactory product. Over-neutralization must be avoided.

2. Complete neutralization of hydrochloric acid casein whey results in the formation of a flocculent precipitate and deterioration in the drying properties; reduction of the acidity from 0·48 to 0·18% by the addition of calcium hydroxide allows successful drying and yields a reasonably satisfactory product. The latter is, however, definitely unpalatable.

3. Acetic acid casein whey can be dried without any previous neutralization to yield an excellent and palatable product.
290. The rheology of butter: II. The relation between rate of shear and shearing stress. The effect of temperature and of reworking on hardness and on structural viscosity
Authors: Dolby R. M.
Published: June 2009

It has been shown that the rate of shear of butter when cut by a wire increases as a power of the load applied to the wire. The values of this power are high (index n = 8 to 15, average 11 at 12.5° C.) and show a high structural viscosity in the butter. There is no indication that butter exhibits a true yield value, but the (rate of shear)/(load) curve is such that a practical yield value is found. The practical yield value (denned as the minimum load required to produce a measurable rate of flow) provides a convenient measure of the hardness of butter. The viscosity of butter decreases rapidly as rate of shear is increased, but the rate of decrease varies from one sample to another. Measurements of spreading capacity should be made at rates of shear comparable with those which occur when butter is spread with a knife.

The effect of temperature over the range 6–18° C. on the hardness and structural viscosity of a number of butter samples has been investigated. The effect of reworking has also been studied.
291. The rheology of butter. III. The effect of variation in butter-making conditions on the hardness of the butter
Authors: Dolby R. M.
Published: June 2009

An investigation of the effect of type of pasteurizer, rate of cooling after pasteurization, temperature during holding and during churning, temperature of wash water and amount of working showed that of these factors the only one which had any marked and consistent effect on the hardness of the butter was the rate of cooling of cream after pasteurization, rapidly cooled cream yielding harder butter. The use of low temperature wash water tended to reduce the hardness of the butter but the effect was small. The other factors had no consistent effect on the hardness of the butter.
302. Bacteriophages for Streptococcus cremoris Phage development at various temperatures
Authors: Hunter G. J. E.
Published: June 2009

The effect of temperature on the growth in milk of several strains of Str. cremoris and their appropriate phages has been investigated. The phage races show a wider diversity of reaction to temperature conditions than do the homologous organisms. They frequently have different optimum growth temperatures quite distinct from the optimum growth temperature of the substrate organisms. Some races fail to multiply at 37° C.

The implication of the results in cheese-making practice is discussed.
339. The consumption of milk among four social classes of consumers
Authors: Bransby E. R.
Published: June 2009

1. Data on milk consumption, and other relevant information, were obtained from 150, 152, 124 and 135 lower working, working, lower professional and professional class families respectively in the city of Leeds during May-June 1939.

2. An account is given of the factors affecting the consumption of liquid milk at school and at home, and of tinned milk. An estimate is made of the amount of milk consumed by children over and under 5 years of age and by adults, and of the nutritional adequacy of the milk consumption of those three groups.

3. An analysis is made of the use of milk in the home and the importance of the three factors: (a) the number of families making milk dishes, (b) the frequency with which the dishes are made, and (c) the amount used in each dish per person per time, in causing differences in the average liquid milk consumption of the four social classes.

4. An estimate is made of the extent to which families were obtaining a proper amount of milk, and the number of the families who were not spending sufficient on food to purchase an adequate amount of milk.

5. It is concluded that in investigations into the consumption of milk, the various social classes should be studied separately, otherwise fundamental differences between them fail to be disclosed.
342. A note on the density of full-cream milk solids
Authors: Lea C. H. , Gane R.
Published: June 2009

A knowledge of the density of air-free milk solids is required for calculation of the quantity of oxygen originally enclosed in sealed cans containing milk powder, and for conversion of percentages of oxygen obtained by analysis of the headspace gas to absolute units. Determination of this figure is a matter of some difficulty owing to the presence of entrapped ‘air’ in the spray-dried product. In the liquid displacement method there is also a danger of error due to incomplete ‘wetting’ of the particles, or to solution of one or other constituent of the powder, while in the gas-displacement method error may be introduced by solution or adsorption of the gas by the powder. Lea, Moran & Smith(1) obtained values of 1·29 by a pyknometer method with ethylene glycol, and 1·31–1·32 by a nitrogen displacement method for full-cream solids containing 27% of fat. Muers & Anderson(2), on the other hand, reported values of 1·26–1·28 by a liquid-displacement method using propylalcohol. Further determinations have therefore been made by various modifications of all these methods.
349. A simple method of conducting the phosphatase test
Authors: Stiven D.
Published: June 2009

The value of the phosphatase reaction for controlling the heat treatment of milk is unquestioned, but the accepted method of estimating phosphatase activity, namely, the colorimetric method of Kay using the phenol reagent of Folin, has three disadvantages:

(1) The number of estimations that can be performed in a given time is limited.

(2) Errors in matching the tints may occur.

(3) Samples of milk may be accidentally contaminated with traces of phenol, and this will lead to too high a Lovibond value.
391. The effect of penicillin in milk on the manufacture of Cheddar cheese
Authors: Hunter G. J. E.
Published: June 2009

Penicillin present in cheese milk affected the performance of various ‘single strain’ starter cultures in the cheese vat.

A concentration of 0·07 penicillin unit/ml, in the milk was sufficient to cause a complete failure or ‘dead’ vat with the most sensitive strain of Str. cremoris. Two strains ceased to produce acid in the later stages of the manufacturing process when the milk contained 0·10 unit/ml. With three other strains the 0·10 unit/ml, level delayed acid development; the experimental vats required 20–40 min. longer than the controls to reach ‘salting’ acidity.

Flash pasteurization temperatures usually employed in cheese-making (150–160° F.) did not appreciably alter the activity of penicillin in the cheese milk.

The quality of the cheese produced was influenced by the rate and extent of acid production by the starter cultures in the vat during manufacture.

Experience in the field indicates that where a large number of cows are treated simultaneously for mastitis, there may be sufficient penicillin in the cheese milk to affect the starter, if the milk from quarters undergoing treatment is included in the bulk milk.
407. The number of sweat glands in the helix of the cow's ear and the milk yield
Authors: Findlay J. D. , Goodall A. Myfanwy , Yang S. H.
Published: June 2009

1. A study has been made of the distribution of the so-called sweat glands in the ears of Ayrshire cattle.

2. The number of sweat glands per unit area of skin in the ear was found to vary greatly from one part of the ear to another and did not appear to be related to the milk yield. It is concluded that it is impossible to use the sweat-gland count in the ear as an indication of the milk-producing capacity of Ayrshire cattle.

3. The number of sweat glands per unit area in the ear of the very young calf was found to be greater than in the fully grown cow, the number being roughly inversely proportional to the surface area of the ear.

4. These findings for Ayrshire cattle are contrary to those published by a number of other workers for cattle of the Red German breed, who claim that any portion of the ear can be used to obtain a sweat-gland count which is closely correlated with milk yield.
441. Equipment for individual-quarter machine milking
Authors: Hall H. S.
Published: June 2009

Individual-quarter machine milking is an important technique in the study of mastitis, dairy-cow management and milking-machine design. In the course of such work equipment for this purpose was found necessary and suitable designs had to be produced.
466. Studies on variations in the solids-not-fat content of milk: II. Variation due to stage in lactation
Authors: Bailey G. L.
Published: June 2009

Curves are presented showing the trends in the solids-not-fat fractions of milk during the course of normal lactation periods.

The trends may vary with pregnancy, age of the cow, and the mean level of the solids-not-fat.
468. Studies on variations in the solids-not-fat content of milk: IV. Long-term trends
Authors: Bailey G. L.
Published: June 2009

It has been shown that a statistically significant decline in the level of solids-not-fat in milk from Dairy Shorthorn first calvers occurred in the months of January, February, March, April and August. The period of the survey was the 12 years from 1935 to 1946.
535. Reactivation of milk phosphatase following heat treatment. III
Authors: Wright R. C. , Tramer J.
Published: June 2009

1. Of a number of farm milks examined, two have been found to develop a positive phosphatase reaction following pasteurization at 161° F. in a small H.T.S.T. plant. This phosphatase was not of bacterial origin but was reactivated milk phosphatase.

2. Considerable variation in reactivation following pasteurization at 161° F. was found to occur using individual churns of the above farm milk from any one milking. Individual cow samples also showed similar variation when tested by the capillary method. No explanation of this variation is offered.

3. Commercial bulk raw milk from road or rail tanks did not develop a positive phosphatase reaction after pasteurization at 161° F. on this plant.

4. Cold storage of pasteurized milk susceptible to reactivation results in less reactivation, and some evidence was obtained that cold storage of the corresponding raw milk also results in less reactivation. No such effect has been observed either using the capillary method or with samples of Uperized milk.

5. Pasteurizing at 170 and 180° F. usually resulted in increased reactivation as compared with that obtained after pasteurization at 161° F. Shortening the holding time at these two higher temperatures sometimes led to a further increase in reactivation.

6. It is shown that no clear relationship exists between the results obtained by plant pasteurization and the capillary method.

7. It is suggested that many of the reported cases of pasteurized cream developing a positive phosphatase reaction on storage can be attributed to reactivation of the enzyme.

8. Practical implications of reactivation in relation to pasteurized milk are discussed.
537. The composition of sow's milk during the course of lactation
Authors: Perrin Dawn R.
Published: June 2009

1. The composition has been studied of the milk of forty-four sows in the course of sixty-eight lactations. The milk was obtained by machine milking following intravenous injection of oxytocin.

2. Definite lactational trends have been observed for all the major constituents, and the third week seems a critical stage for most of the milk components.

3. The mean values for the milk, based on the analyses of over 450 samples from the seventh to fifty-sixth day of the lactation were: fat 9·58 %, protein 6·11 %, lactose 4·62 %, ash 0·92%. Such figures are considered to be rather meaningless for most practical purposes, in view of the marked changes over the course of lactation.

4. The day-to-day variation in the composition of sow's milk has been studied. Whereas the fat value changes considerably, the non-fat constituents show a less marked variation. Difficulties in securing a representative sample of the weekly milk have been overcome by preparing a composite sample from three milMngs within the week.

5. Some preliminary work has been done on variation in the composition during the process of milking. Sequential samples show an erratic fat content, especially during the early part of the lactation. When calculated on a fat-free basis, the protein, lactose and ash contents are relatively constant during the process of milking.
540. A device for rapidly churning small quantities of cream
Authors: Dolby R. M.
Published: June 2009

Cream samples (200–500 ml.) are churned in about 1 min. in a covered beaker by an agitator directly coupled to a ¼ h.p. electric motor. The beater sweeps the whole of the enclosed space so as to prevent thickened cream from collecting in places where it can escape agitation.
543. Methods for the growth and enumeration of anaerobic spore-formers from cheese, with observations on the effect of nisin
Authors: Hirsch A. , Grinsted Elisabeth
Published: June 2009

Severe losses are caused in some types of cheese by the growth of spore-forming anaerobes. The species most commonly involved isClostridium butyricumand its variants, but other clostridia such asCl. sporogenes (Bacillus putrificusof Dorner (1)) may also be concerned. Existing methods for the study of the properties of these organisms are inadequate, a fact on which Rosenberger(2) has commented. This work has been particularly concerned with devising a medium suitable for all clostridia, which is clear, simple to prepare, and which requires no special anaerobic precautions in its use.
544. Factors influencing the lactic acid-producing properties of streptococci used in the manufacture of Cheddar cheese: I. Observations relating inhibitory and stimulatory phenomena
Authors: Jago G. R.
Published: June 2009

1. Many single-strain lactic streptococci used as cheese starters exhibited a difference in susceptibility to an inhibitory substance present in raw and H.T.S.T. pasteurized milk, some being markedly affected whilst others were completely resistant to this inhibitory aubstance.

2. The inhibitory effect of raw or partially heated milk on ‘susceptible’ strains of starter streptococci appears to be a widespread phenomenon. It can be said that the inhibitory substance is normally present in all milk supplies throughout the year. It occurs in milk freshly drawn from the udder aseptically.

3. Heating the milk to boiling-point for variable periods or autoclaving the milk destroys the inhibitory effect of the milk on ‘susceptible’ cultures.

4. The inhibitory substance is closely associated with the fat globules in milk and can exert a marked effect owing to the large surface area exposed.

5. Growth-stimulating substances prepared from extracts of fowl liver, separator slime, and yeast were able to overcome the inhibitory effect when added to raw milk. However, the effect of these substances were markedly depressed on the addition of small amounts of freshly separated cream to the cultures.

6. It is suggested that the above growth-stimulating substances contain a common growth factor which enters into competition with an inhibitory substance closely associated with the fat globule.

7. The inhibitory substance appears to be bacteriostatic in its effect and not bactericidal.

8. Owing to the heat lability of the inhibitory substance and its presence in close association with the fat globule, it is suggested that it may be enzymic in nature.
546. Studies on the secretion of milk of low fat content by cows on diets low in hay and high in concentrates: III. The effect of variations in the amount and physical state of the hay and a comparison of the Shorthorn Friesian breeds
Authors: Balch C. C. , Balch D. A. , Bartlett S. , Hosking Zena D. , Johnson V. W. , Rowland S. J. , Turner Jill
Published: June 2009

1. Four comparable groups of Shorthorn cows were used for an investigation of the effects of various amounts of hay, given with concentrates, on the fat content and yield of milk.

2. During the initial and final control periods all the cows received 16 lb. hay daily and about 4 lb. of a balanced concentrate mixture (flaked maize 50%, weatings 35% and decorticated groundnut cake 15%) per 10 lb. of milk produced. During the experimentaltreatment period of 7 weeks the groups received 12, 8 or 4 lb. hay, or 8 lb. coarsely ground hay, per cow daily respectively, with sufficient of a low protein concentrate to compensate for the reduction in hay, and the balanced mixture as in the control periods.

3. The change from 16 to 12 lb. hay did not affect the fat content of the milk, a small decline being attributable to the advance in stage of lactation, but the mean values for the last 2 weeks of treatment, adjusted for the differences in the initial control period, showed that the milk fat percentage for the groups receiving 8 and 4 lb. hay and 8 lb. ground hay had fallen by 1·16,1·12 and 1·72 respectively by comparison with that for the 12 lb. hay group.

4. A group of Friesian cows was included in the experiment, and received 4 lb. hay during the treatment period. The fall in the fat content of their milk was greater, but not significantly different from, that observed with the corresponding group of Shorthorn cows.

5. In the treatment period the milk yields tended to decline more rapidly than in the control periods, and this taken in conjunction with the falls in fat content was reflected in considerable falls in the yield of milk fat, ranging from 28·4 to 55·2% with diets containing less than 12 lb. hay. Both the fat percentage and fat yields recovered in the final control period.
549. Intramammary pressure changes in the lactating sow: III. The effects of level of dose of oxytocin and the influence of rate of injection
Authors: Whittlestone W. G.
Published: June 2009

The injection of small amounts of oxytocin into the lactating sow has shown that the minimum quantity required to evoke a response in a normal adult animal is of the order of 0·05 i.u. If the injection is prolonged, the dose must be increased to produce a response. Large doses (0·8–1·0 i.u.) given at widely different rates produce multiple ejection pressure graphs with two or more peaks.
562. The steam stripping of taints from liquids. I. An analysis of processing methods with particular reference to the Vacreator
Authors: Scott J. K.
Published: June 2009

The operation of equipment for reducing the amounts of volatile taints in liquids by the use of open or generated steam is explained and analysed. From consideration of material balances for each system and the equilibrium characteristics of the volatile substances, formulae and graphical methods are derived and used to show the degree of taint removal which can be attained by the steam. The methods and charts are used to show the performance of Tandem and Triple Vacreators. The methods presented in the paper can be used for any volatile solute but particular reference is made to two substances having equilibrium constants of 17 and 1·4 because these represent a range of volatilities of particular interest and are approximate values for diacetyl and acetoin which can be used as reference substances.

The effectiveness of any system is shown to depend on the value of a stripping factor which is equal to the product of the equilibrium constant and the pounds of deodorizing steam per lb. of liquid (i.e. F = mV/L). The efficiency of methods where the liquid is contacted several times with fresh steam is shown to be much greater than for single contact. The gain in efficiency for each stage becomes less pronounced with increasing contacts and the maximum efficiency is shown to be limited even for an infinite number of contacts.
564. The properties of New Zealand butters and butterfats: IV. Refractive index and density of the butterfat
Authors: McDowell A. K. R.
Published: June 2009

1. The refractive index and density of butterfats were determined for butters forwarded by twenty factories at 8-week intervals over a period of 3 years. The refractive index (n40) ranged from 1·4535 to 1·4571, with mean weighted value of 1·45492. The density (D60) ranged from 0·8885 to 0·8916, with mean weighted value of 0·89045.

2. Minimum refractive index results were found in the summer butterfats and maximum results in the winter butterfats, i.e. at opposite seasons to the occurrence of the minimum and maximum in Northern European butterfats. Maximum density results were found in late spring butterfats and minimum results in autumn butterfats.

3. The mean monthly results for refractive index and for density of North Island and South Island butterfats showed an appreciable divergence only during the winter months.

4. The correlations between refractive index and iodine value, between density and saponification value, and between density and Reichert value, on 140 butterfats sampled over 1 year were all highly significant.
567. The recorded butterfat content of bulk milk from a herd of White Fulani cattle
Authors: Tasker N.
Published: June 2009

The writer had the opportunity of determining the fat content of morning and evening samples of milk from a herd of White Fulani cattle over a period of 12 months. The notes and tables which follow are the records of this work.
609. Acetone taint in milk due to Bacterium CloacÆ
Authors: Jones G. Elis
Published: June 2009

In the investigation of an outbreak of acetone taint in bulk milk it was: (a) shown not to be due to the lactating animal; (b) reproduced by the inoculation into milk of a strain of Bact. cloacæ isolated from the tainted milk; (c) shown that seventy other strains of coliaerogenes organisms (including sixteen Bact. cloacæ) did not possess this ability to produce an acetone taint.

A search of the literature failed to produce a record of this taint being produced by factors other than acetonemia of the animal.

Note. Since writing the article another strain of Bact. cloacæ giving a positive Rothera's test has been isolated at Wye from a sample of milk which developed a typical sickly sweet taint on storage (Billing, E., personal communication, 5. xii. 55).
616. The size of the fat globules in the milk of diseased cows
Authors: King J. O. L.
Published: June 2009

The results of examining the fat globule size in milk samples from thirty-one cows which were in-patients in a Veterinary Hospital, have been recorded. Eleven of these cows did not develop a body temperature over 102·4° F., and samples collected on the second day after admission and 5 days later were examined and compared. Although the rise in yield was significant, the differences in fat percentage and fat globule size were not. The other twenty cows developed raised body temperatures, and the association between body temperature and milk composition was considered in the following temperature ranges: 104° F. or over, from 102·5–103·9° F., and 102·4° F. or below. The results showed that a rise in body temperature was accompanied by a fall in yield and also by an increase in the fat percentage and in the average fat globule diameter.
622. Infection and mastitis in a dairy herd 1945–53
Authors: Oliver J. , Dodd F. H. , Neave F. K.
Published: June 2009

A description has been given of a dairy herd, its breed composition, history and management over a period of 8 years. A close study of infection and mastitis was made in the herd, and the bacteriological methods used have been outlined. The data collected have been analysed and the methods of analysis have been described. There were 530 complete lactations for which full records were available and, because of the frequency of milk sampling and the care with which the bacteriological and other tests were made, these data are considered to be suitable for a precise study of the effect on the incidence of infection and mastitis of stage of lactation, season of the year, age and previous infections. These factors will be the subject of a later report.
636. The influence of milk yield on fertility in dairy cattle
Authors: Currie Elisabeth J.
Published: June 2009

9234 cows in 524 herds were divided into two groups in each herd, those holding to first service and those not holding to first service. The differences between the milk-yield means of each group in each herd were tested by an analysis of variance procedure, which showed no significant difference in milk production between the two fertility levels. It was also shown that the sample was homogeneous. The study shows that the amount of their milk yield during the month of service does not adversely affect the fertility of dairy cattle.
655. The effect of pH on the extent of splitting or clumping of fat globules caused by agitation of hot cream
Authors: Dolby R. M.
Published: June 2009

The effect of pH on the extent of splitting and clumping of globules in hot cream agitated by treatment in a Vacreator, by vigorous mechanical stirring or by simple aeration has been investigated. The size distribution of globules was determined in cream before and after treatment either by the microscopic method or by a rapid method involving separation of small and large globules by centrifuging and gravity creaming respectively.

It was found that at pH 8 splitting of globules was at a maximum and clumping at a minimum. As the pH of the cream to be treated was lowered towards pH 6, the amount of splitting decreased and clumping increased. The ‘clumping’ of globules in cream during single-stage homogenization was also increased as the pH was lowered.

Practical applications of the observations are suggested.

The thanks of the author are due to Mr J. A. Singleton, superintendent and Mr B. Le Heron, buttermaker of The Dairy Research Institute (N.Z.) experimental factory, for arranging and carrying out the Vacreator treatment of cream; to Dr F. H. McDowall for helpful advice and criticism, and to Miss R. P. Johnson for assistance with microscopic and analytical work.
680. Some properties of the mammary myoepithelium of the sow
Authors: Whittlestone W. G.
Published: June 2009

Simultaneous intramammary pressure recordings were made on pectoral and inguinal mammary glands of the sow. Oxytocin was injected via the ear vein and the nature of the pressure curves resulting from quantities of hormone above physiological level studied. The frequency of the periodic contractions of the mammary myopethelium under these conditions was measured and compared with human uterine responses under similar conditions.

The writer is indebted to Professor H. McK. Carey of the National Women's Hospital, Auckland for the intrauterine pressure graph shown in Fig. 3. Acknowledgement is also made of the technical assistance given during the experiments by Mr E. D. O'Reilly.
Steam distillation of taints from cream: V. Vapour/liquid equilibrium relationships for some α-diketones in lactose solution
Authors: McDowall F. H.
Published: June 2009

1. The effect of 4·5% lactose in solution on the vapour/liquid equilibrium relationship for acetylpropionyl, acetyl-iso-butyryl, acetylvaleryl, acetylcaproyl and acetylbenzoyl has been investigated.

2. There was no appreciable effect on the relationship for acetylpropionyl and acetylbenzoyl.

3. For acetyl-iso-butyryl there was a lowering of the coefficient at low concentration of diketone in the liquid, but at concentrations above 4 p.p.m. there was no appreciable effect.

4. For acetylvaleryl at low concentrations in the liquid the coefficient was lowered, and at concentrations above 3·0 p.p.m. in the liquid it was increased.

5. For acetylcaproyl the coefficient was lowered by presence of 4·5% lactose in the solution.

6. Change in concentration of lactose over the range 0·5—10% had little effect on the vapour/liquid equilibrium coefficient for acetylpropionyl and acetylbenzoyl, but it caused a progressively increased reduction in the coefficient for acetyl-iso-butyryl, acetylvaleryl and acetylcaproyl.
Steam distillation of taints from cream: VIII. Effect of fat content of dairy product on deodorization process
Authors: McDowall F. H.
Published: June 2009

1. In commercial practice dairy liquids of fat contents ranging from 3 to 90% are subjected to deodorization by steam distillation treatment.

2. Increase in fat test of cream causes a rise in the vapour/liquid equilibrium coefficient for tainting substances of low butterfat/skim-milk distribution ratio, and a fall for substances of high-distribution ratio, in cream.

3. Increase in fat content of cream reduces the amount of tainting substance in the cream per unit weight of butterfat in the cream, for substances of all butterfat/skim-milk distribution ratios.

4. Separation of milk to cream of a high fat content greatly facilitates the elimination of substances of low butterfat/skim-milk distribution ratio from the cream and butter.

5. Variation in temperature of separation, by its effect on the distribution ratio for tainting substances, could affect the content of these substances in the final cream, and could possibly cause a change in the character of the cream.

6. In the partition of tainting substance between butter and buttermilk in the churning process, fat content of cream affects the proportion of residual taint passing from the treated cream into the butter.

7. It is pointed out that, because of the effect of salt in increasing the vapour/liquid equilibrium coefficient of some steam volatile substances, the threshold concentration for a tainting substance in butter can be expected to vary with variation in the rate of salting of the butter.
The effect on the amount of residual milk of the interval between milkings, duration of milking, and delay between udder stimulation and milking
Authors: Elliott Gillian M.
Published: June 2009

Using an experimental method of half-udder comparisons the effects on the amount of residual milk of varying milking intervals, the duration of milking, and the delay between the stimulation of milk ejection and the start of milking were measured. Yield of residual milk was not related to the length of milking intervals within the range of 4–16 h but the butterfat content was directly related to the length of the interval. Neither the yield nor the butterfat content of residual milk was affected by a change in the duration of milking of 1 min. A delay between the stimulation of ejection and the start of milking of 6–8 min resulted in increasing the yield of residual milk by about 1 lb.

It is suggested that these results indicate that milk ejection is sufficiently persistent that residual milk is unlikely to be affected by delays between stimulation of milking and the start of milking until they exceed 4–6 min.
Application of the hydrometric method of analysis to the estimation of solids-not-fat production
Authors: Wallace G. M.
Published: June 2009

The effect of preservative tablets added to milk on its composition and density is discussed. A comparison between the S.N.F. content of 10-day composite samples of milk from individual herds after making due allowance for added preservative, and the weighted mean S.N.F. calculated on a daily basis, showed that the 10-day composite sample could be used successfully for estimating S.N.F. hydrometrically. A comparison of the weights of S.N.F. supplied when estimated by gravimetric and hydrometric methods was made for ten herds supplying a commercial plant over a period of 260 days. The mean difference was –0·14% of the gravimetrically estimated weight, S.D. 0·4, and the range was ±0·6%. The result is discussed and is considered of sufficient accuracy to justify, on a technical basis, using the hydrometric method of estimating S.N.F. for determining and, if necessary, paying for the S.N.F. supplied.
The action of rennin on casein The disruption of thek-casein complex
Authors: Beeby R. , Nitschmann Hs.
Published: June 2009

Approximately 30% of the nitrogen of κ-casein was soluble at pH 4·7 after the protein had been treated with rennin at pH 7 while approximately 10% was soluble in 12% trichloroacetic acid (TCA). The material soluble in 12% TCA appeared at a slower rate initially than did the nitrogen soluble at pH 4·7 but as the reaction proceeded it was released more rapidly.

Treating κ-casein with urea, or repeated precipitation of the protein at pH 4·7, caused the formation of material insoluble at pH 7, apparently para-κ-casein. Both treatments appeared to free the same soluble fraction as does rennin acting in low concentration or for a short time.

Low concentrations of rennin (0·07 μg/ml) released only part of the available soluble nitrogen from 2% solutions of whole casein at pH 7. Heating the reaction mixture appeared to restore the casein complex, the restoration being less complete the longer the reaction had proceeded.

It is suggested that κ-casein is not a single protein but a complex, and that the action of rennin is first to open the secondary bonds responsible for the stability of this complex.
Biological estimation of oestrogenic activity in red clover (Trifolium pratense): relative potencies of parts of plant and changes with storage
Authors: Flux D. S. , Munford R. E. , Wilson G. F.
Published: June 2009

Immature ovariectomized mice were used to compare the oestrogenic activities of different parts of the same clover plants; to estimate the relative potencies of biochanin A, genistein and diethylstilboestrol; and to compare the effects of different methods of storage on the oestrogenic potency of red clover leaf and petiole. Test materials were incorporated in the diet fed to the mice and the uterine weight response was used to measure oestrogenic activity.

With material harvested at four different times, the leaf or leaf and petiole had the highest activity; small and large stem fractions of the plant were both relatively less active, and blossom and seed head were inactive.

Comparison of successive estimates of the relative potency of isoflavones and diethylstilboestrol indicated that the relative responsiveness to the two types of oestrogen did not remain constant. Thus comparisons of estimates of oestrogenic activity of plant material, obtained in terms of diethylstilboestrol in different experiments, could be invalid.

The potencies of alcohol, acetone and freeze-dried preparations were compared after storage for 18, 115, 212 and 230 days. Of the procedures tested, the most satisfactory was that in which fresh material was placed in 95% alcohol and the liquor and residue dried and stored at room temperature over concentrated sulphuric acid at reduced pressure.
The oxidative stability of butterfat extracted from Cheddar cheese
Authors: McDowell A. K. R.
Published: June 2009

Cheeses collected monthly for 6 months from 6 factories in the same district were stored for a period of 12 months. At intervals the cheeses were sampled and the fats extracted for oxidation tests. There was no increase in peroxide value, no decrease in induction period and only a slight increase in free fat acidity during storage of the cheeses.
Effects of dilution, freezing and thawing and drying on the dispersibility of isolated fat globule membrane
Authors: Chien H. C. , Richardson T. , Amundson C. H.
Published: June 2009

The effects of dilution, freezing and thawing, and drying on the dispersibility of fat-globule membrane (FGM) preparations were studied. Dilution of FGM favoured aggregation of the lipoprotein particles. Freezing and thawing of FGM had a similar effect. Drying FGM by roller-drying markedly decreased its dispersibility. Drying by low-temperature vacuum-drying only slightly increased the dispersibility of FGM, while freeze-drying and spray-drying gave larger increases in the dispersibility.
Phytanic acid and other branched-chain fatty acid constituents of bovine rumen bacteria
Authors: Hansen R. P.
Published: June 2009

Phytanic acid, 3,7,11,15-tetramethylhexadecanoic acid, which hitherto had been isolated and identified from several natural sources including butterfat, ox perinephric fat and cow plasma, has now been found present in small amounts (2·9%) in the total fatty acids extracted from the rumen bacteria of a fistulated dairy cow fed a diet of clover-grass hay. This C20 multibranched fatty acid was not detected in the dietary clover-grass hay, and it is considered to have been derived from phytol by enzymic activity of the rumen bacteria.
The preparation of cheese curd by a continuous method: the effect of heating the curd in the absence of whey
Authors: Berridge N. J. , Scurlock P. G. , Aston R.
Published: June 2009

Curd was made in a continuous curd-making apparatus (Berridge & Scurlock, 1969) and immediately separated from its whey. Its temperature was maintained at a high level (41–48 °C) as it was moved continuously in the form of a thin layer through a set of rollers. The curd then had a moisture content similar to that of normal curd at the end of scalding in the traditional process. After a suitable period of cheddaring the pH value and the moisture content of the continuously made curd were the same as those normally reached at the same stage in the traditional process.
Studies on the mechanism of gel formation in the California mastitis test reaction
Authors: Nageswararao G. , Derbyshire J. B.
Published: June 2009

The effects of various factors on gel formation in the California Mastitis Test (CMT) were studied to obtain information on the mechanism of the reaction. Death of the leucocytes in milk, produced either by storing the milk at 5°C or by freezing and thawing, markedly reduced the viscosity of the gel formed by the milk with CMT reagent. Samples of skim-milk to which leucocytes were added gave increasingly viscous gels with CMT reagent as the pH was increased to 10·0. Soluble casein increased the viscosity of the gel formed by leucocytes with CMT reagent. The viscosity of the gel was decreased by the addition of CaCl2 and NaCl. On microscopic examination the gel formed in the CMT appeared as an irregularly arranged fibrillar network containing DNA. Deoxyribonuclease I rapidly eliminated the gel-forming property of leucocyte nuclei with CMT reagent, and EDTA inhibited this enzyme activity. Crude protease, trypsin, papain and bacterial protease decreased the gelforming property to different degrees. The presence of EDTA with these enzymes resulted in the formation of a viscous, ropy gel before the addition of CMT reagent. It was concluded that at least a part of the protein of the DNA-protein complex of leucocyte nuclei, in addition to the native polymer of DNA, was necessary for gel formation in the CMT reaction.