bluuebunny/crossref_metadata_2025_split huggingface dataset:
335. Mists containing hypochlorite as germicides in the destruction of air-borne bacteriophages attacking lactic streptococci
Authors: Wolf J. Z. , Nichols Agnes A. , Ineson P. June 
Published: June 2009

1. The germicidal effect of spraying hypochlorite solutions of varying strength on three different phage races of streptococci from cheese starter has been described. It has been shown that fine mists containing 0·003–0·02 p.p.m. av./cl., usually ensure satisfactory destruction of air-borne phage.2. Below a relative humidity of about 50% hypochlorite solutions cause a slight or negligible destruction of bacteriophage particles.3. A gelatine medium has been found useful for collecting phage particles from the air, since it could be liquefied without danger of destruction of the phage after exposure and a quantitative estimation obtained of the phage particles collected.4. When the relative humidity was low the recovery of phage particles from the air was increased.5. Some experiments using mists of resorcinol and propylene glycol are also reported.
364. Studies on the bacteriological flora and keeping quality of pasteurized liquid cream
Authors: Crossley E. L. 
Published: June 2009

1. The special conditions of the cream trade are discussed. Keeping quality is a major consideration which influences all operations and it has been shown that unusually high bacteriological standards of handling are essential.2. The requirements for bacteriological control testing are indicated, together with the limitations of existing standard methods.3. A rough sorting test has been developed which permits sufficiently rapid estimation of the probable keeping quality of heat-treated cream and which is applicable to routine grading of numbers of individual units.4. Data from 2558 samples of heat-treated cream are presented to show the relationship between the colony count, conform test, grading test, and keeping quality.5. Possible sources of bacteriological contamination have been indicated by the examination of 2337 plant samples. Commercial processing methods are discussed and satisfactory practical methods of operation have been developed to ensure a minimal bacterial population.6. The keeping quality of cream has also been studied in relation to the effects of cold storage before distribution and of exposure to atmospheric temperature during distribution.
382. The seasonal distribution of calf and milk sales in north Wales and the probable influence of climatic conditions on the monthly rate of calving and consequent milk production
Authors: Phillips R. , Davies J. L. , Brown E. H. 
Published: June 2009

There appears to be a west to east cline in the four north Wales counties in: (i) the proportion of calves sold during the autumn months September to December; (ii) the proportion of December milk sales in relation to the September sales; (iii) the proportion of the dairy and breeding herd in milk during the winter; (iv) the quarterly rates of conception in heifers during the period 4 December to 4 March. There does not appear to be any relation between percentage winter milk production and percentage tillage area in this region. It is postulated that the west to east cline is dependent mainly upon factors other than husbandry and that climatic conditions, particularly the hours of bright sunshine during the winter months, have a marked influence upon the breeding performance of cows and heifers during the period December to March.This investigation has formed part of the survey of animal health and production in Wales, and thanks are due to the scientific branch of Messrs Cooper, McDougall and Robertson, Berkhamsted, for financial support. Grateful acknowledgement is made to the Ministry of Food, Colwyn Bay, for readiness in providing data and helpful advice; to Messrs Pritchard, Auctioneers, Bangor, and Messrs Beardmore, Auctioneers, Abergele, for permission to examine their records; to the Milk Marketing Board for providing the data on milk sales; to Profs. A. N. Worden and E. G. Bowen for the interest they have taken in the work.
396. Chemical sterilization of dairy equipment. The bactericidal action of chlorine in the presence of protein
Authors: Cox G. A. , Whitehead H. R. 
Published: June 2009

1. Hypochlorite was allowed to react with glycine and with skim milk in various proportions, and the germicidal power of the resultant mixtures was determined.2. The results indicated that chloramino compounds formed by interaction of hypochlorite and protein or amino-acid have a definite but slow disinfecting action against Str. cremoris.3. The chloramino compounds did not appear to be more strongly germicidal at pH 9·5 than at pH 7·0 under the conditions of the experiments.
411. Pseudomonas putrefaciens in New Zealand butter
Authors: Thomson G. I. 
Published: June 2009

1. Using Hammer's litmus milk enrichment technique, a total of ninety-one cultures of Ps. putrefaciens were isolated from 1563 samples of normal salted butter graded for export.2. A correlation was demonstrated between poor hygienic conditions in butter factories and the incidence of Ps. putrefaciens contamination of the butter.
437. Copper and iron in dairy produce. improved methods of analysis
Authors: Perrin Dawn R. , Ruth Lightfoot F. , Moir G. M. 
Published: June 2009

1. Improvements are described in the methods for the extraction and colorimetric estimation of metals in dairy produce, using the carbamate reagent for copper and thiocyanate for iron.2. A combined filtration procedure has been developed to enable both metals to be determined on the same sample, and with slight modifications this procedure has been applied to the analysis of samples of butter, cream, buttermilk and whey.3. The wet-ashing technique has also been improved to enable it to be used for the estimation of both metals on the same digest.4. Comparisons show that the combined filtration method is capable of giving results which agree very well with those yielded by wet-ashing.5. The results of many analyses show that the majority of creamery butter samples have a satisfactorily low content of both copper and iron.6. Many whey butter samples have a rather high metallic content.7. Notes are given on the results obtained when the methods described are applied to other dairy produce.
451. Biochemical and serological properties of some citric acid fermenting streptococci from milk and dairy products
Authors: Swartling F. 
Published: June 2009

1. Thirty-five strains of acetoin producing lactic streptococci isolated from raw milk, from starter cultures and from dairy products were investigated biochemically and serologically.2. The strains are shown to form a homogeneous unit, very similar toStrep. lactisO.J., which species they resemble in cultural behaviour, in growth-temperature range, in tolerance of sodium chloride and heat and in carbohydrate and other fermentations. They differ fromStrep. lactisessentially in their ability to utilize citrate in producing CO2volatile acids and C4-compounds (diacetyl, etc.). With few exceptions they bear no resemblance to the enterococci.3. Serologically the strains are shown to belong to group N and thus the relationship toStrep. lactisis clearly established.4. The strains investigated are shown to be identical withStrep. citrophilusvan Beynum & Pette and almost with certainty, though no direct comparison has yet been possible, withStrep. diacetilactisMatuszewskiet al.Probably they are identical, too, withStrep. diacetyl aromaticusKarnad andStrep. lactis aromaticusJoshi & Ram Ayyar.5. The taxonomic position of the relevant unit is discussed, and it is suggested that it be given species rank under the nameStrep. diacetilactis.
454. Bacteriological aspects of the reworking and blending of stored butter
Authors: Hiscox E. R. , House A. G. 
Published: June 2009

1. The reworking of stored butter stimulates dormant bacteria into renewed growth and, since these are frequently taint-producing organisms, may hasten the deterioration of retail butter.2. Blends of sweet cream and ripened cream (acid) butters may contain a greater variety of organisms than reworked samples of either type, and conditions may be created which are even more favourable for bacterial activity.
465. Studies on variations in the solids-not-fat content of milk: I. Variations in lactation yield, milk-fat percentage and solids-not-fat percentage, that are due to the age of the cow
Authors: Bailey G. L. 
Published: June 2009

1. The coefficient of variation of lactation milk yield was approximately 25% for all age groups. That for lactation milk-fat percentage approximately 10% and that for lactation solids-not-fat percentage only 3%. The last two coefficients tended to increase with the age of the cow.2. Lactation milk yield was least with first calvers and rose to a maximum for sixth calvers. Milk quality was highest with first calvers.3. No tendency to vary with the season of calving could be found for any lactation record of any age group.4. During the first years of the herd's existence there was a small negative correlation between lactation milk yield and lactation milk-fat percentage. This has disappeared in more recent years.5. There was no correlation between lactation milk yield and lactation solids-not-fat percentage.6. There was a small (r = +0·40 approximately) positive correlation between lactation milk-fat percentage and lactation solids-not-fat percentage.
493. Concerning the interpretation of observations, obtained from records and experiments, on milking dairy cows
Authors: Cox C. P. 
Published: June 2009

1. Some questions concerning the interpretation of observations on milking dairy cattle are considered.2. A formula is presented for analysing the contributions of changes in the numerator and denominator to the changes in a percentage or fraction, and the formula is applied to changes in the composition of milk.3. The depressions of the butterfat and solids-not-fat percentages consequent on diets reduced in hay in a dairy-cattle feeding experiment are examined with this constituent analysis.The contributions of changes in the magnitudes of the aqueous, butterfat and solids-not-fat constituents to the difference between the butterfat percentages of cows on two treatments, 18 lb. hay/day (control) and 6 lb. hay /day, are about equal. There is an apparent qualitative difference between the effects of the two non-control treatments, and a reduced yield of butterfat would alone largely account for the lower butterfat percentage of cows on the 2 lb. hay /day treatment.
513. The effect of different cream treatments during the pasteurization process on the size distribution of fat globules in cream and butter
Authors: Dolby R. M. 
Published: June 2009

A method for determining the size distribution of fat globules in cream has been described. A thin film (20 μ) of the diluted cream on a microscope slide is preferred to a deeper preparation (0·1 mm.) in a counting chamber in which rise of fat globules to the upper surface is necessary for easy observation. The latter method is less convenient and can give too low an estimate of the proportion of the smallest globules (1 μ and under).Cream should be diluted 1 in 50 and the concentration of gelatin in the dilution should be sufficient (4–6%) to give a rapid gel formation. The mixture should be cooled till the gelatin thickens before being transferred to the slide if it is to give the most uniform distribution of globules.It is shown that Vacreator-treatment of cream causes a considerable increase in the proportion of fat present as globules less than 2 μ and a small increase in the proportion present as globules over 10 μ in diameter. Flash-pasteurization, on the other hand, causes a slight decrease in the proportion of fat present as small globules and a considerable increase in that present as large globules.Butter from flash-pasteurized cream contains numerous large fat globules and fat aggregates, while butter from Vacreator-treated cream contains few large globules. It is suggested that the more uniform subdivision of fat in butter from Vacreator-treated cream explains why butter from Vacreator-treated cream is superior in texture to butter from flash-pasteurized cream.
525. The deterioration of milking rubbers: III. The effect of farm treatment
Authors: Cooper J. H. , Gardner E. R. 
Published: June 2009

The accumulation of fat in a rubber liner occurs mainly in two regions, the mouthpiece and the portion of the barrel in contact with the teat. It is suggested that the mouthpiece is attacked by body fats and udder salves mainly, whereas the barrel absorbs milkfats from milk trapped between the rubber and teat. The accumulation of fat increases linearly with the number of milkings performed.The loss of milking efficiency is connected with the stiffness of the rubber compound, and this latter property decreases linearly with the number of milkings. The length of service of a liner on the farm is shown to be largely dependent on the individual farmer and his standards of efficiency and cleanliness.The presence of fat in rubber leads to an enhanced rate of oxidation and consequent loss of physical properties. This has been confirmed in practice. An increase in the tension of a liner increases the rate of swelling and the souring of milk on rubber gives a similar result. The use of detergents has no direct deleterious effect on the physical properties of rubber. They are not effective in removing fat from below the surface layers. The occurrence of ozone-cracking of parts of milk liners or tubing, which are under tension, is discussed and the use of waxes in the compound as a remedy is described.
572. The heat coagulation of milk
Authors: Pyne G. T. , McHenry Kathleen A. 
Published: June 2009

1. A study of the compositional factors which affect the heat coagulation of milk has been undertaken.2. Calcium-ion concentration and colloidal phosphate content appear to be the chief factors determining the tendency of a milk to coagulate on heating.3. Acidity (mainly derived from thermal decomposition of lactose and casein) and heat denaturation of casein are supplementary coagulation factors which develop during the heating process.4. Lactose, as the main source of heat-developed acidity, is an important secondary factor in heat coagulation, but not an essential one. Coagulation can proceed, though more slowly, in its absence. The serum proteins play no part in the phenomenon.5. A provisional theory of the heat coagulation of milk based on these findings is put forward.
582. Immersion cleaning of milking equipment
Authors: Thiel C. C. , Clough P. A. , Clegg L. F. L. , Akam D. N. , Gruber Marie , Hirons Elizabeth 
Published: June 2009

A method of cleaning milking equipment is described which involves the immersion of all items coming into contact with milk in a caustic soda solution for the whole period between milkings. It is expected that this method of maintaining the equipment in satisfactory bacteriological condition would need less attention to detail than existing techniques. The procedure outlined may only be applied to apparatus which can be packed into a basket no larger than can be readily handled. It therefore applies only to direct-to-can milking equipment, and suitable milking and immersion cleaning apparatus are described.The process has been tried for a year on 8 commercial farms. The results are promising in that milk of good quality has been consistently produced, but the bacteriological state of the milking clusters was often below present standards. Deposition of calcium soap and inorganic calcium salts was marked on farms where the total hardness of the water was of the order of 200 p.p.m. Work is continuing.
590. Quantitative estimation of the amino-acids in Cheddar cheese and their importance in flavour
Authors: Mabbitt L. A. 
Published: June 2009

Quantitative data have been obtained concerning the amounts of individual amino-acids present in the aqueous phase of Cheddar cheese during the ripening process. They differed from the amounts found in casein by the larger amounts of basic amino-acids, smaller quantities of proline and the presence of ornithine.Tasting tests showed that amino-acids contribute an important background flavour to Cheddar cheese.An unidentified substance or group of substances, representing 7–9% of the total ninhydrin-positive material in the serum of ripe cheese, has been observed.The author gratefully acknowledges the interest and advice of Dr N. J. Berridge, and the technical assistance of Mrs K. Kelly. Thanks are also due to Miss H. R. Chapman for making the cheese.
594. The effect of heat treatment on the lipolytic flora of cream
Authors: El Sadek G. M. , Richards T. 
Published: June 2009

The effect of ‘hold’ and ‘H.T.S.T.’ heat treatment on cream was a 97–100% reduction in the tributyrinolytic flora. There was no significant difference between the two methods in this respect. The tributyrin-splitting organisms have been tested for their ‘true’ lipolytic effect upon triolein; of 967 organisms tested 55 % attacked triolein. In raw cream the most numerous lipolytic organisms were of the Micrococci and Pseudomonads groups, whereas in heated cream the former were by far the predominant lipolytic organisms.The result of storing cream at 8–11° C. for 24 hr. was an 8- to 13-fold increase in tributy-rinolytic organisms, mostly of Gram-negative rods many of which attacked triolein. The effect of heat treatment nullified this increase and the lipolytic flora of heated cream was much the same whether or not the cream was stored before heating.The triolein media incorporated two new indicator dye combinations which were successful but a third, nile blue, was found to be strongly inhibitory to the majority of triolein-splitting organisms.
598. A comparison of the Gerber and Röse Gottlieb methods for the determination of fat in milk
Authors: Crocker W. P. , Jenkins D. I. , Provan A. L. , Macdonald F. J. , Rowland S. J. , White J. C. D. 
Published: June 2009

The Gerber method (B.S. 696:1936) and the Röse Gottlieb method (B.S. 1741:1951) for the determination of the fat content of milk have been compared on 208 samples of milk covering the range of 2·5–6·0% fat. The following relationship was found between the Gerber percentage (G) and the Röse Gottlieb percentage (RG):G = 1·036 RG – 0·097. Thus, for milks containing 3·0, 4·0, 5·0 and 6·0% fat, as determined by the gravimetric Röse Gottlieb method, the Gerber test gave results which were higher, on the average, by 0·01, 0·05, 0·08 and 0·12% fat respectively.If the capacity of the Gerber milk pipette were reduced from 11·04 ml. of water, as specified at present, to 10·94 ml., the average results obtained by the two methods would be in agreement for milks with a fat content around 3·6%, the average for milk in England and Wales, and the difference between the results by the two methods would, for most purposes, be negligible over the normal range of fat content.Tables are given, for the 11·04 and 10·94 ml. milk pipettes, showing the average differences between the results by the two methods for various values of Gerber fat percentage.
606. A variability study in firmness in cheese using the ball-compressor test
Authors: Cox C. P. , Baron Margaret 
Published: June 2009

A variability study of ball-compressor readings on the upper faces of 10 Cheddar cheeses has shown that:1. Percentage elasticity readings were generally less discriminating than total deformation readings.2. As measured by the total deformation, there were firmness gradients across the faces of the cheeses, which tended to increase in firmness from the centre outwards.Further experimentation to determine consistent firmness differences on cheeses has been recommended and meanwhile, from preliminary examination of firmness discrimination, it is suggested that four total deformation readings may give sufficient accuracy for many routine purposes.
610. Destruction of Mycobacterium tuberculosis and Phosphatase in heat treated cream
Authors: Aschaffenburg R. , Briggs C. A. E. , Crossley E. L. , Rothwell J. 
Published: June 2009

Batches of cream were artificially infected with M. tuberculosis, and subjected to varying heat treatments under conditions of H.T.S.T. and holder pasteurization. Guinea-pig and phosphatase tests were applied to the treated creams.The minimum time-temperature conditions required for the inactivation of M. tuberculosis and phosphatase were found to be similar to those pertaining to milk.The practical difficulties of controlling the effciency of cream pasteurization are discussed.
625. Udder infections in the ‘dry period’: III. The method of drying-off cows at the end of lactation
Authors: Oliver J. , Dodd F. H. , Neave F. K. 
Published: June 2009

1. An experimental study was made of the effect of drying-off by ‘stop’ or intermittent milking on the incidence of new infection in the early dry period of dairy cows. Ninety-one and ninety-seven dry periods were examined following the treatments, and the results were analysed on a cow and quarter basis.2. The incidence of new infection was similar for groups of cows dried off by ‘stop’ or intermittent milking.3. The quarters of cows that were not infected on drying-off showed a significantly higher incidence (P <0·05) of new infection following ‘stop’ than following intermittent milking.4. Of the cows that were not infected at the time of drying off, those which had a previous history of infection showed a significantly higher (P <0·01) incidence of new dry-period infection than cows that had not been infected before.5. There was a much higher incidence of new infection in cows that were already infected on drying-off compared with cows free from infection at that time.6. About half of all the new dry-period infections persisted until the next lactation, and about one-third of these resulted in mastitis in the affected quarter.7. The method of drying-off had no effect on infections that were already established in quarters going dry.8. The types of pathogen causing infection were similar for both methods of drying-off.9. The method of ending lactation did not affect milk yield in the lactation following the dry period studied.
644. The influence of penicillin on the manufacture and ripening of Cheddar cheese
Authors: Whitehead H. R. , Lane D. J. 
Published: June 2009

The addition of penicillin to cheese milk had the effect of delaying acid production by starter in the cheese curd; any effect on cheese quality could be traced to the delay in acid production and to a high final pH in the cheese. There was no indication of any direct effect of penicillin on the ripening process.A concentration of 0·10 unit/ml. of penicillin in the cheese milk was a borderline amount with the particular starters which were used. Cheese quality was sometimes adversely affected. A smaller concentration (0·05 unit/ml.) delayed the cheese-making process slightly but had no adverse effect in final cheese quality. Higher concentrations regularly resulted in poor quality cheese.Penicillinase added to cheese milk neutralized any penicillin present but with a short time of contact of about 30 min., a large excess of penicillinase had to be used.
682. Some results on the variability of the clot-on-boiling test
Authors: Hosking Zena D. , Barkworth H. 
Published: June 2009

The C.O.B. test has been carried out at 15 min. intervals on raw milk samples stored at 20°C. to examine worker and replicate variability. Within experimental limitations, the differences between workers were not significant (P>0·05) and, in general, good agreement was found between the five replicates examined for each milk sample, coefficients of variation less than 4·0%. The change from absence to presence of a precipitate generally occurred with successive tests, but there were indications that the times to increased intensity of clotting differed with samples.Captain H. Barkworth was responsible for the plan and design of these experiments which were carried out by members of his staff at Shardlow.