bluuebunny/crossref_metadata_2025 huggingface dataset:
William Pitt and the origins of the Loyalist Association Movement of 1792
Authors: Duffy Michael
Published: June 2009

This article presents new and conclusive evidence to resolve the long-running controversy over whether the loyalist association movement of 1792 was spontaneous or was crafted by government. It shows that Pitt and his colleagues did not know in advance of John Reeves's proposals for the Crown and Anchor association before they were published on 23 November and it suggests who Reeves's original collaborators probably were. It then goes on to show how Pitt and his cousin, Lord Grenville, confronted with many demands and proposals for associations at this time, quickly seized upon the Reeves project as the most adaptable to their own ends and produced a new draft, redefining his proposals in the directions they were prepared to see such a movement take. This they induced Reeves to publish as a second declaration on 26 November and they went on to promote as the example and inspiration for a wider association movement.
18. Starters
Authors: Knudsen Søncke
Published: June 2009

The term “starters” as used in dairying is understood to refer to cultures of lactic acid bacteria which induce “souring” when inoculated into milk, cream or other product. Souring will usually occur without the use of starters, but the results will be erratic. With the help of starters, however, the reaction can be controlled so that it proceeds in a desired direction. The term generally suggests those starters which are used in the making of butter, but in its widest sense it must includeallcultures which are used in the dairy for the production of any type of souring.
73. Phosphorus Compounds of Milk. VI. The Effect of Heat on Milk Phosphatase. A Simple Method for Distinguishing Raw from Pasteurised Milk, Raw from Pasteurised Cream, and Butter made from Raw Cream from that made from Pasteurised Cream
Authors: Kay H. D. , Graham W. R.
Published: June 2009

A method is described for the quantitative determination of phosphatase in raw milk. Using this method, it has been found that phosphatase is sufficiently thermolabile to be destroyed completely by pasteurisation if this process is properly carried out. The absence of phosphatase from a sample of milk or cream indicates with a fair degree of certainty that the milk or cream has been heated sufficiently to destroy such pathogenic organisms as were originally present, though it is of course no guarantee that the product is free from these organisms at the time of testing.

A simple, qualitative test-tube method is described which may be used for differentiating between raw and heated milk, or between raw and heated cream, and which with slight modifications may also be used for distinguishing between butters made from raw or from heated cream.
83. Observations on Sudden Changes in the Rate of Acid Formation in Milk by Cultures of Lactic Streptococci
Authors: Whitehead H. R. , Cox G. A.
Published: June 2009

1. Some cases of sudden failure in the growth of cheese starter cultures are described.

2. It is shown that the cause lies in the method of pasteurisation of the milk in which the cultures are grown.

3. Aeration of the milk immediately before the inoculation of the culture is shown with certain cultures to have an inhibitory efEect on the growth of the organisms. Normal starter cultures are not affected by aeration of the milk; they may, however, suddenly develop this sensitivity to aeration and may just as suddenly revert to the normal state.

4. The mere absorption of atmospheric oxygen while milk is being cooled after pasteurisation in a wide-mouthed cylindrical vessel may constitute an aeration sufficient to inhibit sensitive cultures of lactic streptococci. Milk pasteurised and cooled in conical flasks plugged with cotton-wool does not reabsorb sufficient oxygen to lead to inhibition, provided that the flasks are not violently agitated.

5. The possible mechanism of the inhibition of the sensitive streptococci is discussed. Evidence is brought forward which tends to show that the action is connected with the oxidation-reduction reactions by means of which the organisms normally obtain their growth energy.

6. The practical significance of the phenomenon in the process of cheese manufacture is emphasised.
92. An Aerobic Acid-Fast Actinomyces in Cow's Milk Due to an Udder Infection
Authors: Gray J. D. Allan
Published: June 2009

The isolation from cow's milk of an organism allied to Actinomyces farcinicus merits recording on account of the rarity in this country of such organisms and on account of failure to find in the literature a description of the organism.
107. Studies On the Chemistry of Cheddar Cheese Making. I. The Mineral Content of Cheese and Whey
Authors: McDowall F. H. , Dolby R. M.
Published: June 2009

1. Analyses have been made of the wheys obtained at various stages in the manufacture of Cheddar cheese.

2. There is shown to be a steady rise in the concentrations of calcium and phosphorus in the wheys throughout the process up to salting. The calcium rises much more rapidly than the phosphorus.

3. After salting there is a sudden temporary fall in the concentration of both calcium and phosphorus in the whey, the calcium fall being particularly pronounced.

4. The concentration of calcium and phosphorus in the whey vary in accordance with the titratable acidity of the whey.

5. In normal cheese making some 60 per cent, of the calcium and 57 per cent, of the phosphorus in the milk is retained in the cheese.

6. Of the minerals lost in the whey some 86 per cent, of the calcium and 90 per cent, of the phosphorus escape before running.

7. An increase in the acidity of the milk before renneting increases the loss of minerals in the whey and reduces the calcium content of the cheese.
143. The Comparative Values of the Plate Count and the Modified Methylene-Blue Reduction Test as Routine Methods for Grading Milk
Authors: Nichols A. A. , Edwards S. J.
Published: June 2009

During the past twenty years the plate count has been largely employed as a means of assessing the hygienic quality of milk. There is no doubt that for this purpose it has proved to be of great value, and the marked improvement which has taken place in the quality of the milk of many producers is largely attributable to its use.
156. The composition of milk and whey, with special reference to the partition of calcium and phosphorus
Authors: Ling E. R.
Published: June 2009

1. The means and standard deviations of analytical data obtained from fifty-four samples of mixed milk (alternate a.m. and p.m.) and whey from the College herd of Dairy Shorthorns are presented in Table I. The samples were taken at intervals during the period late September 1935 to November 1936.

2. While no outstanding differences in composition are evident between morning and evening samples, the time of rennet coagulation was appreciably greater with the evening's samples. Evidence is presented to show that the longer time of cold storage of these samples must be regarded as a contributory cause of this effect.

3. In the discussion of the mean values, special treatment has been given to the partition of calcium and phosphorus between the four phases, soluble and insoluble, organic and inorganic. The caseinogen values are examined in the light of current theories.
185. The incidence of mastitis in cows yielding milk low in solids-not-fat
Authors: Foot A. S. , Shattock P. M. F.
Published: June 2009

1. In a field investigation covering twenty-nine herds, an average of 19·5% of the animals in milk during the first three months of 1937 were yielding milk low in solids-not-fat, estimated by the routine method, at two consecutive milkings.

2. Of the low solids-not-fat cows which were not stale, evidence of mastitis infection was found in an average of 61·5% of cases. Re-examination of some negative animals suggests that the total infection amounted to about 70%.

3. There were apparently at least twice as many “subclinical” cases of mastitis as clinical cases.
222. Bacteriological studies of spraydried milk powder
Authors: Nichols Agnes A.
Published: June 2009

1. Over 400 samples of spray-dried. milk powder from eight factories operating in England and Scotland have been examined. These samples were taken at different stages of the day's run and were obtained from several types of plant situated in widely different districts. Samples were taken in both the summer and winter months. The samples were, therefore, sufficiently representative to enable general conclusions to be drawn regarding the factors affecting bacteriological quality.

2. In reconstituting milk powders for bacteriological examination it is necessary to ensure (i) that the sample is sufficiently large to be representative, and (ii) that external contamination is avoided during weighing and handling. The use of a 20 g. sample is advocated. Complete reconstitution of the powder is best obtained by shaking the sample with glass beads in a 180 ml. water blank which is contained in a screw-capped bottle. Details are also given of the methods used in bacteriological examination of the samples and for the isolation of pure cultures from them.
262. The microbiology of silage made by the addition of mineral acids to crops rich in protein
Authors: Cunningham A. , Smith A. M.
Published: June 2009

1. The microflora of A.I.V. silage consists mainly of lactic acid bacteria—lactobacilli, streptococci, micrococci and sarcinae. Some samples also contain yeasts and yeast-like organisms.

2. Among the lactobacilli, both homo- and heterofermentative types are represented. The former include strains ofLactobacillus plantarum(Orla- Jensen) Bergey et. al.; in the heterofermentative groupL. brevis(Orla-Jensen) Bergey et al. has been found.

3. Cultures of a motile homofermentative lactobacillus were isolated; this appears to be a new type. Among the unidentified heterofermentative lactobacilli, forms which may prove to be similar to the inactive group of Pederson were encountered.

4. The homofermentative streptococci were found to belong to the Streptococcus lactis group; the heterofermentative forms were identified withLeuconostoc mesenteroides(Cienkowski) van Tieghem.

5. Strains of unidentified homofermentative micrococci and sarcinae were isolated and shown to possess characteristics not usually associated with organisms of these types.

6. Streptococci, micrococci and motile lactobacilli were found mainly in fodder recently ensiled; the majority of the lactobacilli and sarcinae were associated with the older samples.

7. The characteristics which proved to be most valuable for the differentiations of the organisms were ability to produce carbon dioxide, percentage of lactic acid formed and lactic-acetic acid ratio.
268. Subclinical staphylococcus mastitis in herds free from streptococcus mastitis, and its effect upon milk composition
Authors: Shattock P. M. F. , Mattick E. C. V.
Published: June 2009

In the milk of herds “free” from streptococcus infection, the presence of staphylococci has been shown to accompany chemical changes in the composition and abnormalities of pH.

In mastitis control schemes, based on Str. agalactiae infection, cases of staphylococcus infection are missed because of suppression of growth on the routine crystal violet blood agar of Edwards. Further, as clinical cases of staphylococcus mastitis causing serious disturbance are comparatively rare, the subclinical type may be present to a considerable extent and yet remain unsuspected. Thus in herds free from streptococcus mastitis, we have found that in 428 “cowtests” staphylococci werefound in 21 %. No clinical case was observed, although careful records of all abnormalities of udders and milks were kept.

The data which we have obtained show that staphylococcus infection accompanies changes of chemical composition which may be of importance in the preparation of milk products, but before categorical statements can be made more observations are obviously necessary.
275. Starter cultures for cheese manufacture: Further attempts to eliminate failures due to bacteriophage
Authors: Whitehead H. R. , Hunter G. J. E.
Published: June 2009

Bacteriophages for lactic streptococci were found to occur in the atmosphere of commercial cheese factories. Finely divided particles of whey emitted from the whey separator appeared to be the main vehicle for the air-borne phage although whey-contaminated dust probably also played a part. The concentration of air-borne phage was sometimes so great that, with the use of a normal bacteriological aseptic technique, it was impossible to prevent infection of the starter cultures for more than a few propagations. Protection of the starter from air-borne phage eliminated phage failures.

The question of the origin of bacteriophage is discussed in the light of the recognition of the prevalence of air-borne phage. The occurrence of air-borne infection could account for most of the instances of starter failures which were previously thought to be due to spontaneous phage development within cultures.
306. A study ofBacillus subtilisand related organisms
Authors: Gibson T.
Published: June 2009

A group of species, comprisingBacillus subtilisand related organisms, may be differentiated from other members of the genusBacillusby (a) morphology and (b) the production of acid and acetylmethylcarbinol from glucose. The group may be divided into three species:

(1)B. subtilisCohnemend. Prazmowski, the synonyms of which includeB. aterrimus, B. globigii, B. mesentericus, B. niger, B. panis, andB. vulgatus.

(2)B. pumilusGottheil, which resembles strains of (1) that produce a smooth glossy growth. It differs in failing to secrete diastase and in other features, but its separation as a distinct species is still an open question. It is sometimes identified asB. mesentericus.

(3)B. licheniformis(Weigmann) Gibson, the synonyms of which includeB. subtilis(as used by Ford),B. globigiiandB. mesentericus ruber. This species may be differentiated from (1) and (2) by its cultural characters, slow proteolytic action, vigorous CO2production and ability to grow anaerobically.
307. The occurrence in winter of milk with a low content of solids-not-fat
Authors: Rowland S. J.
Published: June 2009

Data are given which show that the solids-not-fat content of the milk produced in a certain dairying area in the early months of 1942 and 1943 was unusually low, a high proportion of the individual herds yielding milk containing less than the presumptive standard of 8·5% solids-not-fat. The freezing-point depression of this milk was normal. The solids-not-fat content showed substantial improvement in May. It is suggested that the low level of solids-not-fat was due to a low plane of nutrition of the cow.
333. The coliform flora of milk and dairy products
Authors: Crossley E. L.
Published: June 2009

1. The sources of error and general significance of the presumptive coliform test have been studied, with special reference to manufactured dairy products.

2. Eosine methylene blue agar has been found reasonably satisfactory for isolation of cultures but unsatisfactory as a direct plating medium.

3. A wide survey of the coliform flora of raw milk and milk products has been made over a period of 11 years. The data were collected from 24,952 samples and include the incidence of presumptive positive tests at each stage of manufacturing processes, the occurrence of ‘false-positive’ tests, the detailed distribution of coliform types in individual dairy products, and some preliminary observations on ‘heat-resistant’ coliform strains.

4. Material examined included raw milk, pasteurized milk, ice cream, milk powder, condensed milk, pasteurized cream, clotted cream, butter, soft cheese, Cheddar cheese, processed cheese, swabs of dairy plant, churn rinses, and the atmosphere of dairy factories.

5. Detailed confirmatory tests were performed on 2490 presumptive positives, from which 2508 coliform cultures were isolated and classified.

6. A general ecological survey of the frequency of individual coliform types in dairying operations as a whole has been attempted.

7. Particular factors which may affect the distribution of coliform types in specific products or situations have been shown to include heat resistance, resistance to drying, chemical composition of the substrate, the effect of storage, and conditions prevailing on plant surfaces. It is suggested that the coliform flora may be partly the result of adaptation to conditions associated with each individual product.

8. The value of the presumptive coliform test has been discussed in respect of public health requirements, as a plant-control method, and in relation to economic aspects. The test is believed to be of great utility in the plant-control laboratory but of little value for public health purposes.
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.
375. The seasonal distribution of calf and milk sales in west Wales and the probable influence of climatic conditions on the rate of calving during the autumn months and on the consequent milk production
Authors: Phillips R. , Davies J. L.
Published: June 2009

It is suggested that the seasonal distribution of the sale of surplus calves through the collecting centres of the Ministry of Food in west Wales during the years 1943–6 is a reasonably accurate reflexion of the rate of calving in the areas associated with these centres. It is shown that between the centres there is a considerable difference in the seasonal distribution of calf sales, and that the percentage numbers of autumn calf sales (September to December) show a gradual decline from the westerly coastal centres to the easterly inland ones. It is also found that the figures for the milk production and particularly the milk deliveries into the factories during the period September to December support the above suggestion.
378. The effect of penicillin on lactic streptococci
Authors: Hunter G. J. E.
Published: June 2009

Ten strains of ‘starter’ streptococci were found to be susceptible to penicillin.Streptococcus cremorisstrains were markedly inhibited under the conditions employed by doses of 0·10 unit/ml.Str. lactisstrains were not inhibited to the same degree unless 0·25–0·30 unit/ml. was present in the milk. These results would indicate that if penicillin is used extensively by farmers and the milk from treated quarters is included in the factory supply, difficulties may arise in cheese manufacture, especially when the more sensitiveStr. cremorisstrains are used as starter.
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.
401. Cheese grading. Mechanical properties compared with quality assessed subjectively
Authors: Harper R. , Baron M.
Published: June 2009

An experiment is described in which ratings on some 200 cheese made on 31 different days were rated for firmness, quality, springiness and crumbliness, both when 2 weeks and 8 weeks old. Some of the relationships between the ratings are discussed, in particular the ratings for firmness and quality. By means of the firmness ratings made on the cheese at 2 weeks, twenty-eight cheese out of 211 could have been screened off, and of these twenty-eight, nine were subsequently seriously down-graded for quality. Only two cheese which were not screened off developed unsatisfactorily to the same degree. Individual differences between judges are noted, especially with regard to quality. The cheese-maker considers the cheese to be about 1 point higher in quality (on a 7-point scale) than the remaining judges. One judge who criticizes adversely about three times as many cheese as the remainder of the judges also down-grades about six batches of cheese which are not down-graded by the remaining judges.
402. Phage-carrying cultures as cheese starters
Authors: Hunter G. J. E. , Whitehead H. R.
Published: June 2009

Cultures of lactic streptococci partially resistant against a phage race and growing in regular association with that race are, as a result of the presence of the phage, protected from attack by some other races of phage. Such phage-carrying cultures were tried as cheese starters in commercial factories under conditions where no protection for the starter against air-borne phage was given. The results were quite satisfactory for several months, but eventually there appeared in the commercial factories races of phage which would attack the phage-carrying culture and thus depress or completely check acid development in the cheese vats. It seems likely that the large number of phage races which evidently exist in nature would make a complete protection along these lines very difficult to accomplish.
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.
431. Two samples of 7-year-old Cheddar cheese
Authors: Hiscox Edith R.
Published: June 2009

During the autumn of 1946, samples of two Cheddar cheese, one of Canadian, the other of New Zealand manufacture, which had been held in a frozen state (in cold store) for about 7 years were presented to this Institute.
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.
438. The viscosity temperature coefficient of homogenized milk
Authors: Caffyn J. E.
Published: June 2009

1. The viscosity temperature coefficient of homogenized milk has been determined with an estimated accuracy of 1%.

2. The effect of temperature on the viscosity has been investigated in some greater detail.
448. Machine milking rate and mastitis
Authors: Dodd F. H. , Neave F. K.
Published: June 2009

It is generally accepted that the udder possesses two main defence mechanisms against mastitis infections. The teat sphincter acts as a barrier against the entry of the pathogenic frequently present on the skin of the teats, and internal factors prevent the bacteria which gain access from setting up an infection. In recent years studies have been made on the relative importance of these two mechanisms, and particular attention has been paid to the relation of teat patency or ease of milking with the incidence of disease. Little (1) stressed the importance of the intact sphincter as a barrier, and suggested that the sphincters of older cows relax, making them more susceptible to infection. In an attempt to overcome the disadvantages of the manual assessment of teat patency, Espe & Cannon (2) used a special instrument. The results were not wholly satisfactory and no correlation with mastitis was found. More recently, Murphy (3) manually examined the teats of at least eighty-seven cows and found a trend towards a higher incidence of infection in quarters with patent teats. This latter author did not agree that relaxing of the teat sphincters with advance in age could account for the increased susceptibility of older cows to streptococcal mastitis (4). While Murnane (5) could not confirm Murphy's results, McEwan & Cooper (6), again using the manual method, obtained further evidence definitely suggesting that easy milking cows were more prone to mastitis. Although Stuart & Lancaster (7) found evidence confirming the importance of the teat orifice, they concluded that it was of less importance than those factors operating within the udder.
450. The effect of the presence of air on the heating of full milk bottles by steam
Authors: Thiel C. C. , Burton H.
Published: June 2009

Heating by means of saturated steam is used widely in the dairy industry in many
processes. One application is autoclaving, a process not confined to the laboratory but used also for the preparation of sterilized milk(1). It is well recognized that the presence of air in autoclaves depresses the temperature of the heating medium when control of the process is based on measurement of pressure, but it does not appear to be generally appreciated, at least in the dairy industry, that air can depress the rate of heating of the load even when thermostatic devices are used to control the autoclave temperature. In the first place air will tend to accumulate in areas remote from the steam inlet in large vessels, with consequent reduction in partial steam pressure, and hence steam temperature, in these areas. Where the atmosphere temperature is maintained another effect occurs. This second effect is due to insulating layers of air which form on the cool surfaces of the load as the steam fraction of the mixed atmosphere condenses. A blanket of air thus formed is unable to disperse because of the general movement of the mixed atmosphere to the condensing surface.
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.
642. Penicillin in milk: II. The incidence of penicillin
Authors: Berridge N. J.
Published: June 2009

An examination of over 5000 milk samples has shown that penicillin is frequently present. Its concentration, however, is usually below the level which is believed to be necessary to cause significant interference in cheese-making, but a significant proportion of the samples contained more than a third of this quantity. This suggests that conditions under which difficulty would arise are not remote.
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.