bluuebunny/crossref_metadata_2025_split huggingface dataset:
386. Variations in morphology of Streptococcus lactis when grown in raw and heated milk
Authors: Morris C. S. , Edwards M. A. 
Published: June 2009

1. Streptococcus lactis cultures were found to vary considerably in their morphological characters when grown in raw and heated milk.2. This variation in morphology was found to be the main cause for the difference in colony counts between inoculated raw milk and milk heated to 70° C. for 1 hr. over a 6 hr. incubation period at 37° C.3. Similar T.M.C.'S on inoculated raw and heated milk during incubation at 37° C. explained why the methylene-blue reduction times were the same.4. It is thought that denaturation of protein may be responsible for the production of short chains in heated milk.5. The by-products of growth of Str. lactis are responsible for the production of short chains in raw milk after a long incubation time at 37° C.
395. The influence of alkalinity on the germicidal action of hypochlorites
Authors: Chaplin C. E. , Johns C. K. 
Published: June 2009

Survivor curves show that, under conditions likely to be found in practice, hypochlorite solutions of low alkalinity disinfect milk films on surfaces more rapidly than those of greater alkalinity.Dehydration of the milk film results in slower disinfection rates by both neutral and alkaline solutions.Increasing the milk content in the film reduces the rate of disinfection and reduces the effect of the neutral solution to a greater extent than the alkaline.
414. Experiments on milking technique: 7. The effect of subjecting dairy cows, for a complete lactation, to a rigid control of the duration of milking
Authors: Dodd F. H. , Foot A. S. , Henriques Ettie , Neave F. K. 
Published: June 2009

1. Thirty-eight first-calf heifers in two equal groups were subjected for complete lactations to a rigid control of the duration of milking to either 4 or 8 min.2. The treatment had no major effect on the milking rates of either group.3. Whilst 4 min. was insufficient time to milk out completely the udders of about half the animals on this treatment, the machines on the 8 min. treatment were generally left on for a period after milk flow had stopped.4. There was no significant difference between the 305-day lactation yields of the two groups or in the persistency. The 4 min. treatment did, however, decrease the yield of milk and fat in early lactation.5. The 8 min. cows had more clinical and subclinical mastitis, though they did not have a higher proportion of eroded teats nor higher Whiteside test readings.6. Teat erosion appeared to be correlated with slow milking.
415. Factors affecting the rate of machine milking
Authors: Baxter Eleanor S. , Clarke Pamela M. , Dodd F. H. , Foot A. S. 
Published: June 2009

1. A study was made of the milking of the two hind quarters of four cows by teat cup and by teat cannula at three levels of vacuum and by teat cannula at atmospheric pressure.2. The eight quarters milked at significantly different maximum rates by teat cup but at nearly the same rate through a teat cannula, suggesting that the teat orifice is a very important factor controlling rate of milking.3. The maximum rate of milking by both teat cup and teat cannula increased with increasing level of vacuum from 11 to 20 in. Hg. The rate of increase in the teat-cup milking was greater than in the cannula milking, suggesting that the teat orifice was stretched open at the higher levels of vacuum.4. The average amount of strippings increased at the higher level of vacuum in teat-cup milking, due apparently to teat-cup crawl.
416. The effect of bacterial infection on the milk yield of the individual quarters of the cow's udder
Authors: Crossman Joan V. , Dodd F. H. , Lee J. M. , Neave F. K. 
Published: June 2009

A study has been made of the effect of udder infections on the proportionate yield and composition of the milk of individual quarters of over 100 cows, and the data from eleven of these cows have been presented.Typical examples have been given showing that subclinical Streptococcus and haemolytic Staphylococcus infections may persist for months and either cause a gradual reduction in the proportionate yield, and solids-not-fat percentage of a quarter or have no measurable effect, and that both types of reaction may occur simultaneously in the same udder.Examples also show that following penicillin treatment of clinical cases caused by streptococci and staphylococci there is little recovery in the proportionate yield of the treated quarter until the following lactation, when recovery may be complete.
424. A study of lactation as affected by heredity and environment
Authors: Sikka L. C. 
Published: June 2009

1. A study has been made of the interrelationships between persistency and maximum yield as components of the lactation curve, and of the importance of environment and heredity in determining the shape of the lactation curve of Ayrshire cows.2. Persistency was defined as the linear constant of the exponential curve expressed as a percentage,maximum yieldas the highest 30-day yield as calculated from the records, andtotal yieldas the yield of milk from 15 days to 8½ months after calving.3. The study was based on milk records computed by the official method of the Scottish Milk Records Association. The data used in much of the work was obtained from five herds of Ayrshire cows and involved 2392 lactations during the period 1920–39.4. In an exploratory test involving 100 lactations it was found that the exponential curve fitted ninety-five of the lactation curves and that the fit was improved in forty-eight of these ninety-five curves by using the parabolic exponential curve. Five of the lactations were too erratic to be fitted by any simple mathematical curve.
426. Some bacteriological aspects of the deterioration of pasteurized milk
Authors: Ashton T. R. 
Published: June 2009

1. Examinations have been made of milk pasteurized by the L.T. ‘Holder’ and H.T.S.T. processes using the same original bulk raw milk. In the preparation of samples care was taken to eliminate the possibility of post-pasteurization contamination. It was hoped that any differences found would be due solely to the effects of the pasteurizing processes above.2. Samples were examined by (a) colony counts and coliform tests when fresh and after ageing at 18°C. for 24 and 48 hr., (b) methylene-blue and resazurin reduction tests when fresh and after ageing at 18°C. for 45½hr., (c) keeping quality at 18°C. to end-point of 68% alcohol and clot-on-boiling tests. All bacteriological and dye reduction tests were carried out at incubation temperatures of 37, 30 and 22°C.3. In seven trials the experiments were repeated after storage of the original raw milk for 24 hr. at 40–50°F. (4·4–10·0°C.).4. Some detailed examinations were made of the bacterial floras of the raw and corresponding pasteurized milks, both when fresh and after ageing.
429. Studies on Egyptian Domiati cheese
Authors: Fahmi A. H. , Sharara H. A. 
Published: June 2009

In the first part of this study, brief notes are given on the better known varieties of the soft pickled group of cheese which the authors believe to be best suited to warm climatic conditions.Domiati cheese, a variety of this group, characterized by the addition of an appreciable amount of salt to the milk prior to rennetting, is described in detail. An outline of the steps of its manufacture, the pickling process, and the effect of the amount of salt added to the milk on the composition of the resulting cheese is given.In the second part the effects of varying additions of salt to both cows' and buffaloes' milk on rennet coagulation, rate of whey drainage, chemical composition and yield of cheese and whey were investigated.
443. Keeping quality and raw-milk grading: III. Comparison of keeping quality tests and dye tests in milk control (results of a field trial)
Authors: Rowlands A. , Hosking Zena 
Published: June 2009

1. The results discussed in this part of the report were obtained by examination of milk samples taken at approximately fortnightly intervals throughout a period of one year from 298 farms in eight widely separated areas of England and Wales. The samples were examined by the routine resazurin test, the methylene-blue (4½/5½ hr.) test, the methylene-blue (½ hr.) test and the temperature-compensated keeping quality test using clot-on-boiling (c.o.b.) to determine the end-point. For the first three tests, the treatment of the samples and the standards applied conformed to those prescribed officially for these tests in England and Wales. Details are given of the treatment of samples and testing procedure for the temperature-compensated c.o.b. test. With this test two standards, equivalent to a residual keeping quality at 22° C. of 21 and 24 hr. from 9 a.m. on the day of collection of the milk from the farms, for both evening and morning milk were used.2. The results are analysed on the basis of the proportion of farms and of samples passing or failing the different tests, the effect of shade atmospheric temperature on the incidence of failures and the relationship between the standards imposed by the c.o.b. tests and the official methylene-blue (4½/5½ hr.) test.The proportion of farms and of samples passing each test was much higher in winter than in summer and was directly related to the prevailing shade atmospheric temperature. However, a proportion of farms was consistently able to comply with the standards. No more than 5% of the total failures by any test could be ascribed to the 60 (20%) best farms, whereas the 60 (20%) worst farms were responsible for as many as 37–60% of the total failures from the 298 farms.
452. Bacteriological tests for milk sampled during distribution to the consumer
Authors: Rowlands A. , Hosking Zena 
Published: June 2009

1. This survey was undertaken to select a test for the official examination of the keeping quality of milk, both raw and pasteurized, sampled during its distribution to the consumer. Forty-five laboratories in England and Wales collaborated in the survey and together tested 20,159 samples during the year May 1949–April 1950.2. Failures with each test were lower in winter than in summer, and increased with increasing shade temperature. However, the proportion of failures for all samples tested in any one month at maximum shade temperatures up to 70° F., or even 75° F., was not appreciably higher than at temperatures up to 65° F. Of the samples examined during June to September, 62% were taken on days when the maximum shade temperature exceeded 65° F.Whatever test is used for the control of milk it is reasonable to expect that at least 75% of samples taken during a given period should reach the required standard. Because of the lower incidence of failures in winter than in summer, this requirement should apply to tests done during a period of 6 months rather than one of a year.
461. ‘Broken’ or ‘bitty‘ cream in raw and pasteurized milk
Authors: Stone M. Jean , Rowlands A. 
Published: June 2009

Of 161 cultures of aerobic sporeformers isolated from raw and pasteurized milk 96 were found to be B. cereus, 27 B. mycoides, 17 B. subtilis, 11 B. sphaericus, 3 B. megatherium, 2 B. pumilus, 1 B. firmus and 4 were unidentified strains.Typical broken cream followed by rapid sweet curdling of sterile milk was produced by 36 of 39 strains of B. cereus and 5 strains of B. mycoides examined. Three strains of B. cereus failed to produce broken cream. These 3 strains were atypical in that they failed to produce lecithinase, unlike the remaining 93 strains isolated during this study. Other species of aerobic sporing bacilli tested, including 17 strains of B. subtilis, 10 of B. sphaericus, 2 of B. megatherium, 2 of B. pumilus and 1 of B. firmus, all failed to produce broken cream and in fact produced no visual change in milk within 48 hr. at 22° C.Under the conditions of our experiments, 48 out of 60 samples of fresh farm milk and 12 out of 14 samples of freshly bottled pasteurized milk developed broken cream within 18 hr. at 22° C. followed by sweet curdling within a further 24 hr. Strains of B. cereus or B. mycoides were isolated from all samples showing broken cream, but only 3 atypical strains of B. cereus were isolated from the 14 samples which did not develop the fault.It seems that the production of broken cream is in some way associated with the production of lecithinase by B. cereus and B. mycoides. This view is supported by the fact that three non-lecithinase producing strains of B. cereus were also unable to produce broken cream. However, attempts to reproduce the fault by adding a concentrated culture filtrate to sterile milk or cream were unsuccessful.Because of the widespread distribution of spores of B. cereus and B. mycoides in both raw and pasteurized milk, the absolute prevention of broken cream does not seem possible, but preliminary observations suggest that maintenance of milk at 5° C. or lower from the time of pasteurization until delivery to the consumer may sufficiently delay the onset of the fault to obviate the difficulty in practice except in very hot weather in households where insufficient care is taken to keep milk cool.
476. Observations on the influence of inhibitory substances produced by the lactobacilli of Gruyère cheese on the development of anaerobic spore-formers
Authors: Hirsch A. , McClintock Mary , Mocquot G. 
Published: June 2009

1. The failure of clostridia to produce a butyric acid fermentation, when known to be present in Swiss-type cheese, is discussed.2. It is suggested that inhibitory substances produced by the predominating lactic flora of young cheese are partly responsible for the suppression of the fermentation.3. Details are given of the techniques used to investigate this supposition.4. The evidence was obtained by examining fifty-one samples of Gruyère cheese, 78% of which were contaminated with clostridia. 85% of the samples contained inhibitory lactobacilli.5. In 30% of the samples the inhibitory phenomena were sufficiently marked to give clear zones of inhibition againstStaphylococcus aureuswhen a suspension of cheese was placed in penicillin cups.6. Inhibition ofClostridium butyricumwas demonstrated with pure cultures of lactobacilli. The cultures could grow at temperatures from 30 to 50° C, but were inhibitory only at certain temperatures of incubation which appear to be a strain characteristic.7. The inhibitory substance(s) concerned is not nisin because it is acid and heat labile.
485. The effect of temperature on the development of broken cream
Authors: Stone M. Jean 
Published: June 2009

Three strains ofB. cereuswere grown in milk at nine different temperature combinations. Broken cream could be prevented by holding milk at 5° C. or lower for 24 hr. before transferring to 15 or 18° C. for a further 24 hr., but with a subsequent period of storage at 22° C. the fault was not prevented. Broken cream developed after storage at 10° C. followed by 18 and 22° C., but not in milk kept at 10° C. and then transferred to 15° C. After preliminary storage at 15° C. the fault appeared within a further 24 hr. regardless of the subsequent storage temperature.With two strains ofB. cereusit was observed that pasteurization accelerated spore germination and hence the development of the fault. With low levels of inoculum there was delay in the appearance of the fault with one strain of the organism.In twenty-four samples of commerically pasteurized milk it was shown that the fault could be controlled by refrigeration at 5° C. before distribution except when the subsequent temperature was allowed to rise to 22° C.Contrary to the suggestion made by Davis (15) preliminary observations indicate that the growth ofB. cereusand the development of broken cream is not inhibited by the presence of acid-producing organisms such asStr. lactis.
486. The action of the lecithinase of Bacillus cereus on the globule membrane of milk fat
Authors: Stone M. Jean 
Published: June 2009

An effect simulating broken cream in whole milk was produced when Bacillus cereus was grown in washed cream at 22° C. A similar but less marked effect was obtained when a concentrated culture filtrate of B. cereus was added to washed cream.Microscopic examination of washed cream to which B. cereus or its concentrated filtrate had been added showed that the fat-globule membranes had been broken down. The hydrolysis of lecithin in washed cream in which B. cereus had grown was demonstrated by qualitative estimation of free choline.Since these results could not be reproduced when a non-lecithinase-producing strain of B. cereus or its concentrated culture filtrate was added to washed cream, it appears that the hydrolysis of the lecithin of the fat-globule membrane is at least partly responsible for the formation of broken cream.
491. The effect of pre-heating milk at 230° F. (110° C) on the keeping quality of spray-dried whole milk
Authors: White J. C. D. , Waite R. , Hawley H. B. , Clark J. G. , Henry Kathleen M. 
Published: June 2009

1. Three samples of spray-dried whole milk were made from milk pre-heated at 190, 230° and 230° F. with regenerative cooling to 190° F., in an A.P.V. H.M. Paraflow Heat Exchanger and dried in a Kestner plant. The powders were packed in plain tin-plate cans and stored at 17, 37 and 47° C. The keeping quality of the powders was determined by examination at intervals for palatability, absorption of oxygen and peroxide value of the fat. The biological value and true digestibility of the protein of the powders were estimated in rat-feeding experiments initially and after 6 months' storage. The breadmaking properties of the powders were also examined.2. The keeping quality, biological and baking tests showed that the three milk powders were very much alike, and that no advantage was gained by raising the preheating temperature of the liquid milk from 190 to 230° F.
511. Observations on the serological typing of group N (‘lactic’) streptococci
Authors: Briggs C. A. E. , Newland L. G. M. 
Published: June 2009

1. Agglutinating type sera were prepared in rabbits for fourteen representative strains in a collection of sixty-eight group N (‘lactic’) streptococci.2. Common type antigens, distinct for each named species, were found in strains ofStr. lactis(inhibitory varieties),Str. diacetilactisandStr. cremoris.3. Certain individuals in each of the named ‘groups’ contained additional heterologous antigens, some of which were identical to heterologous (but not the common) antigens in strains of other groups.4. Quantitative differences in the representation of common antigens were also found.5.Str. lactisOJ andStr. cremorisHP were shown to be mirror images of each other so far as their type antigens are concerned, containing two common type antigens in inverse proportions of 4:1 respectively.Str. lactisOJ possesses the ‘cremoris group’ type antigen, and the implications of this observation are discussed.
515. Cheddar-cheese flavour and its relation to tyramine production by lactic acid bacteria
Authors: Dacre J. C. 
Published: June 2009

1. Cultures ofStr. faecalis, L. plantarumand a strain ofLeuconostoc, when added to cheese milk, all brought about an increase in Cheddar flavour intensity in the resultant cheese.2. Examination of the cheeses for tyramine content showed that the formation of the amine bore no relationship to the increases in flavour intensity. The production of tyramine appeared to be merely incidental in the cheese-ripening process.3. A survey among the lactic acid bacteria disclosed only one species containing a significant amount of the L( – )-tyrosine decarboxylase enzyme—L. brevis. This species added to cheese milk causes an objectionable ‘yeasty’ flavour in the final cheese.
545. Studies of the secretion of milk of low fat content by cows on diets low in hay and high in concentrates: II. The effect of the protein content of concentrates
Authors: Balch C. C. , Balch D. A. , Bartlett S. , Cox C. P. , Rowland S. J. , Turner Jill 
Published: June 2009

1. Twenty cows were used in an experiment to compare the effect of five different diets on the fat and solids-not-fat content and yield of milk.2. During initial and final control periods all the cows received 18 lb. hay daily and about 4 lb. of a balanced concentrate mixture (crude protein 16·5%) per 10 lb. of milk produced. In the experimental period, which lasted 7 weeks, a control group of four cows remained on this diet. Two similar groups received daily only 4 lb. hay and about 6 lb. extra concentrates; in these groups the concentrates contained 22·3% crude protein. The remaining two groups received similar treatment except that the concentrates contained only 11·6% crude protein. In addition, 10 1b. macerated delignified straw pulp (containing 1 lb. crude fibre) were given to half the cows receiving each type of concentrate. At the end of the experiment the cows were turned out to grass.3. With the diets low in hay and high in concentrates there was a fall in the fat content of the milk, with some variability in the response of individual cows (see 4 below). With the concentrates high in protein, the fall appeared to be rather slower than with those low in protein, but by the sixth and seventh weeks of experimental treatment it was estimated to be 0·67% fat with high and 0·72% fat with low protein concentrates. The experiment showed, therefore, that serious falls in fat content may occur in cows early in lactation with diets of 4 lb. hay and concentrates containing 22·3 or 11·6% protein. The addition of a limited amount of crude fibre as straw pulp brought about no recovery in milk fat content.4. The extent of the depression brought about by the change to diets low in hay diminished with advancing stage of lactation.
556. The use of seaweed meals in concentrate mixtures for dairy cows
Authors: Burt A. W. A. , Bartlett S. , Rowland S. J. 
Published: June 2009

The relative effects upon milk yield and composition of three concentrate mixtures containing 10% of two types of seaweed meal (Ascophyllum nodosum and Laminaria cloustoni) and an oatfeed-salt mixture, have been observed.Each cow received daily a basal ration of 30 lb. marrowstem kale and 18 lb. hay for maintenance and the first 1½ gal. of milk and 31½ lb. concentrates for each gallon thereafter.No significant effects of treatment upon milk yield or fat percentage were observed.The milk produced on the oatfeed-salt mixture had a slightly but significantly higher solids-not-fat content than that on the mixtures containing seaweed meals.The results showed that seaweed meals have a nutritive value no greater than that of a mixture of 7 parts oatfeed and 1 part salt, which had an estimated starch equivalent of only 39.In view of the relatively high cost, low palatability and low nutritive value of seaweed meals, their possible use in the feeding of dairy cows appears very limited.
560. The incidence of penicillin in milk supplies
Authors: Storrs F. C. , Hiett-Brown Winifred 
Published: June 2009

1. In surveys carried out in the summer of 1951, 1·4% of churn milk contained penicillin in one group of tests and 2·8% in another. Bulk milk was free from this antibiotic.2. In a further survey carried out in the winter of 1953, 3·2% of composite churn milk contained penicillin. Bulk milk was again free, but small aggregates of a few supplies used for making bulk starters sometimes contained penicillin.3. Of twenty samples of milk and seven of whey examined during 1951–3, and which were implicated in starter failure, only two milks and one whey contained penicillin in significant amounts.4. The rate of excretion of penicillin from the composite milk of a herd containing thirty-seven treated cows was determined. Milk up to the fifth milking contained sufficient penicillin to cause starter inhibition.