bluuebunny/crossref_metadata_2025_split huggingface dataset:
685. Factors influencing the destruction by heat of vitamin B12in milk
Authors: Ford J. E. 
Published: June 2009

The processing of liquid milk, particularly sterilization ‘in-bottle’ or ‘in-can’, may cause considerable destruction of its content of vitamin B12. This loss can be greatly reduced by thorough deaeration of the milk before heating.The author would like to thank Dr S. K. Kon for helpful advice and criticism.
Studies of the secretion of milk of low fat content by cows on diets low in hay and high in concentrates: VII. The effect of administration of volatile fatty acids to cows giving normal milk and milk of low fat content
Authors: Balch C. C. , Rowland S. J. 
Published: June 2009

1. The administration of 0·5–1·5 kg. sodium acetate to cows in which the milk fat percentage had been reduced by diets low in hay and high in concentrates usually brought about an appreciable improvement in fat percentage. The extent of the response varied from slight to complete. The Reichert value of the milk fat fell with diets low in hay, but was raised by administration of acetate.2. The daily administration of 500 g. sodium acetate to cows receiving diets containing normal levels of hay and concentrates according to their milk yields did not affect the milk fat content.3. The daily administration of 414 g. sodium propionate did not restore fat percentages lowered by the diets low in hay. Butyrate appeared, in a test with one cow, to possess the restorative properties of acetate.4. With diets containing either 50 lb. silage as the sole roughage or 60 lb. fodder beet and only 6 lb. hay, fat percentages were the same as with a normal diet containing 16 lb. hay.
Viscosity changes in concentrated skim-milk treated with alkali, urea and calcium-complexing agents: II. The influence of concentration, temperature and rate of shear
Authors: Beeby R. , Lee J. W. 
Published: June 2009

An essentially exponential relationship between maximum viscosity and concentration of casein was observed for concentrated skim-milk undergoing treatment with calcium hydroxide. Positive temperature coefficients of viscosity were found for samples treated with alkali, while negative coefficients were found with sodium hexametaphosphate. The time of appearance of the maximum viscosity was independent of temperature in concentrated skim-milk treated with sodium or calcium hydroxide; however, when sodium hexametaphosphate was used the maximum appeared earlier at higher temperatures. The viscosity of all systems studied decreased with increasing rate of shear, the deviation from Newtonian being greatest when the viscosity was at its maximum. The effects are explained in terms of a swelling and disintegration of the casein micelles as was postulated in the previous paper.The authors wish to thank Miss Audrey K. Morris, Dairy Research Section, C.S.I.R.O., Melbourne, for valuable technical assistance, and to express their appreciation for the helpful advice of other members of this Section during the preparation of the manuscript.
The genus Leuconostoc and its nomenclature
Authors: Garvie Ellen I. 
Published: June 2009

SummaryA preliminary examination of strains of leuconostocs collected from many different laboratories has resulted in a division into six groups. Some of these groups are heterogeneous. The nameLeuconostoc cremorisis used in preference toLeuconostoc citrovorumfor the non-sucrose fermenting species. Reasons are given. Other arguments lead to the conclusion thatStreptococcus kefir(Evans) should be regarded as a synonym ofLeuconostoc mesenteroides, and the nameLeuconostoc lactisis used in preference toStreptococcus kefir(Abd-el-Malek & Gibson).
Some volatile compounds in New Zealand Cheddar cheese and their possible significance in flavour formation: III. Time of first appearance of volatile carbonyl compounds during ripening
Authors: Harvey R. J. , Walker J. R. L. 
Published: June 2009

SummaryTwo Cheddar cheeses were analysed for aldehydes and methyl ketones at intervals during the ripening period. One-day-old cheese was found to contain acetaldehyde and acetone, together with traces of butan-2-one and pentan-2-one. As the cheese matured heptan-2-one, nonan-2-one and undecan-2-one appeared, and the concentrations of all these compounds progressively increased.
Dye-binding methods for estimation of protein in milk
Authors: Dolby R. M. 
Published: June 2009

SummaryThe amido black and orange G methods for protein estimation in milk were investigated. The quantity of dye required for complete precipitation of a given quantity of milk protein was determined.Dye samples of various degrees of purity all gave a linear relation between protein and dye precipitation, as determined by optical density, but with the less pure samples slightly less dye was bound per unit weight of protein.Amido black, though reacting with protein in the same molar ratio as orange G, gave a much more sensitive optical indication of protein content.In milks of individual cows there was a relatively constant relationship between dye values and Kjeldahl protein from 3 to 4 days after calving until 3 to 4 weeks before the end of lactation. Late lactation milks gave about 5% higher dye values than did normal milks of the same protein content.The relation of dye precipitation to Kjeldahl nitrogen was the same for casein as for total nitrogen in normal milks.
The effect of the presence of penicillinase producing micrococci on the growth of cheese and yogurt starters in milk contaminated with penicillin
Authors: Reiter B. , Vazquez D. , Newland L. G. M. 
Published: June 2009

SummaryCoagulase-negative micrococci isolated from the cow's udder, when cultivated together with cheese and yogurt starters in milk containing 0·3 I.U./ml of penicillin, contributed sufficient penicillinase to permit normal rates of acid production by the starters. Subcultures of such ‘mixed’ cultures also grew at normal rates in milk contaminated with penicillin at the same level.The possibility of using such micrococci to protect the starter organisms in both the preparation of bulk starters and during manufacture of cheese and yogurt is discussed.
Gas packing milk powder with a mixture of nitrogen and hydrogen in the presence of palladium catalyst
Authors: Abbot J. , Waite R. , Hearne J. F. 
Published: June 2009

SummaryWhole and skimmed milk spray dried powders have been gas packed by two methods, and the chemical and physical changes taking place during storage at 17 and 37 °C for two years have been measured. The conventional method of double gas packing with nitrogen, with an interval of several days for desorption, was used as a control for a new method employing a single gas packing with a mixture of nitrogen (90%) and hydrogen (10%) plus the inclusion within the can of a solid catalyst pellet containing palladium.The new system was more effective in removing oxygen and in maintaining an almost oxygen free atmosphere within the cans. Used on a commercial scale it would have several important advantages over the conventional method, and both whole and skimmed milk powders packed in this way would probably be usable after storage for 10 years at normal temperatures.Because of the low general level of oxygen in all the cans packed by both methods and because of the low moisture content there was little difference in the keeping quality of the powders. What little there was, however, was in favour of the new method.
A preliminary investigation of the importance of clostridia in the production of rancid flavour in Cheddar cheese
Authors: Goudkov A. V. , Sharpe M. Elisabeth 
Published: June 2009

SummaryBacteriological examination of 15 pairs of Cheddar cheeses, of which one of each pair was made aseptically, showed that there was a relationship between the development of rancid flavour and the numbers ofClostridium tyrobutyricumpresent. Other species of clostridia,Cl. beijerinkii, Cl. sporogenesandCl. perfringens, were also present but occurred only as spores. Conditions for the growth ofCl. tyrobutyricumappeared to be more favourable in the aseptically made cheese; it is suggested that the adventitious bacterial flora of the non-aseptically made cheese, which gains access during cheesemaking, has some inhibitory effect on the growth of this organism.
The component fatty acids of the colostral fat and milk fat of the sow
Authors: Duncan W. R. H. , Garton G. A. 
Published: June 2009

SummaryThe fatty acid composition of colostral and milk fat samples representative of the total secretion of the nursing mammae of each of 3 sows was determined by gas-liquid chromatography. In both colostral and milk fats, acids of chain length C16and C18accounted for more than 90% of the total fatty acids present; colostral fat contained a higher proportion of oleic acid and linoleic acid and less palmitic acid and palmitoleic acid than normal milk fat. Structural studies on milk triglycerides showed that, as in pig depot fat, palmitic acid is preferentially esterified to the secondary alcoholic group (2-position) of the glycerol molecules with the C18acids (stearic, oleic and linoleic acids) being present for the most part in the 1- and 3- positions.
A compound responsible for metallic flavour in dairy products: II. Theoretical consideration of the mechanism of formation of oct-1-en-3-one
Authors: Wilkinson R. A. , Stark W. 
Published: June 2009

SummaryPossible mechanisms are considered for the formation of a metallic flavour component, oct-1-en-3-one, in a vacuum-packed butterfat-antioxidant-synergist mixture, and in washed cream and butter with free access to atmospheric oxygen. The oct-1-en-3-one is likely to be derived from linoleic or arachidonic acids, or both. A complex of reactions linking oxygen, catalysts, substrate, radicals, and antioxidants is discussed. Pathways for the production of intermediates giving rise to oct-1-en-3-one are suggested for systems with free and with limited access to oxygen. These mechanisms would involve secondary oxidations with formation of polyfunctional monomers and would be competing for oxygen with those giving rise to polymers. The reasons why they compete to a significant extent are discussed in relation to the detailed environmental conditions including lipid reactivity, effective oxygen pressurein situ, steric effects at phase boundaries and the role of acidity and of ionic intermediates.
The sensitivity of bovine staphylococci, streptococci and corynebacteria to cloxacillin and various other antibiotics
Authors: Jones A. , Higgs T. M. , Neave F. K. , Smith A. 
Published: June 2009

SummaryThe sensitivities of isolates of bovine staphylococci, corynebacteria and streptococci to various antibiotics were determined. The growth of various strains of Staphylococcus aureus was inhibited by the following range of concentrations of antibiotic: cloxacillin, 0·07 to 0·6 μg/ml; penicillin G, 0·018 to > 250 μg/ml; streptomycin, 1·25 to > 250 µg/ml; novobiocin, 0·15 to 25 μg/ml; chlortetracycline, 0·6 to 10 µg/ml. The concentrations of cloxacillin required to inhibit growth were between 0·15 and 1·25 μg/ml for strains of Streptococcus agalactiae; 0·07 to 0·3 μg/ml for strains of Streptococcus dysgalactiae and 0·15 to 0·6 μg/ml for strains of Streptococcus uberis.The corynebacteria were generally sensitive to the penicillins (ampicillin, penicillin G, phenethicillin and cloxacillin), but showed least sensitivity to cloxacillin which had a similar activity to that of chlortetracycline, neomycin and oleandomycin. Chloramphenicol and streptomycin were less active than the penicillins and novobiocin showed little activity against Corynebacterium ulcerans.A clear relationship was confirmed between the sensitivity of staphylococci to cloxacillin and penicillin G. Some indication was found of an association between the sensitivity of staphylococci to cloxacillin and the success of cloxacillin intramammary therapy in the non-lactating udder. There was no evidence of a change in the sensitivity of Staph. aureus following exposure to cloxacillin in the non-lactating udder.
Size distribution of fat globules in cow's milk during milking, measured with a Coulter counter
Authors: Kernohan Elizabeth A. , Lepherd E. E. 
Published: June 2009

SummaryA Coulter counter was used to measure the diameters and numbers of fat globules in serial samples taken during a single milking of each of 8 cows. Milk fat percentages of samples were estimated by the Babcock method. The average globule diameter, globule number and fat percentage all increased during milking. Regression analyses indicated that fat percentage was a stronger function of fat globule diameter than of globule number. The results are discussed with relation to the rise in fat percentage that occurs during milking.
Impact force as a possible cause of mechanical transfer of bacteria to the interior of the cow's teat
Authors: Thiel C. C. , Thomas Carol L. , Westgarth D. R. , Reiter B. 
Published: June 2009

SummaryUsing bacterial endotoxin as a tracer material, it has been shown that a jet of liquid impinging on the end of the teat for 1 min after milk flow had ceased during machine milking could force material past the barrier of the streak canal. Positive results were obtained when the maximum pressure at the centre of the impact area was about 0·25 bar, with a considerably higher frequency of positives at 0·3–0·5 bar. It seems possible that such impact pressures might occur during milking and cause transfer of infective material to the teat sinus. Impact force could arise when milk returned to the teatcup liner as the result of local or general conditions of instability in the milking machine vacuum.
Influence of aggregation on the susceptibility of casein to proteolysis
Authors: Fox P. F. 
Published: June 2009

SummaryThe susceptibility of the casein in milk to proteolysis was shown to be greatly influenced by its state of aggregation. In normal milk, where the casein is largely in micellar form, the αs1- and β-caseins are almost inaccessible to proteolysis. On removal of the colloidal phosphate, the casein micelles disintegrate, rendering the components, especially the αs1-casein, accessible to proteolysis. The role of colloidal calcium phosphate in the casein micelle is believed to be that of a non-specific aggregating agent which can be effectively replaced by calcium. Dissolved colloidal phosphate can be effectively reformed by elevation of the pH of colloidal phosphate-free (CPF) milk before equilibrium dialysis. Addition of κ-casein to CPF milk also causes aggregation of the component caseins but the micelles formed are smaller than those of normal milk.The behaviour of micellar β-casein differs considerably from that of micellar αs1-casein. The evidence suggests that part of the β-casein freely dissociates either outside or within the micelle when the temperature is reduced. The temperature dependence of the susceptibility of β-casein to proteolysis was similar in skim-milk and in solutions of sodium caseinate, and increased as the temperature was reduced. αs1-Casein was quite resistant to proteolysis in normal milk but became susceptible when the micelle structure was disrupted on removal of colloidal phosphate.It is concluded that limited proteolysis may prove a valuable technique in the study of casein micelle structure.
Extraction of the 260 nm-absorbing material from Group N streptococci as a method for estimating cell growth
Authors: Hogg D. McC. , Jago G. R. 
Published: June 2009

SummaryA method is described for estimating the growth of Group N streptococci in milk and other media by measuring the 260 nm-absorbing material extracted from the cells with 0·1 M-NaOH at 100°C. A good correlation between the absorbance at 260 nm of the hot alkali extracts and the dry weight of the cells was obtained for cultures of Streptococcus lactis during the logarithmic and early stationary phases of growth.
Comparison of milks processed by the direct and indirect methods of ultra-high-temperature sterilization. III. A note on the results for spore destruction obtained with an experimental ultra-high-temperature milk sterilizer
Authors: Burto H. 
Published: June 2009

SummaryThe bacteriological results of Franklin, Underwood, Perkin & Burton (1970) are analysed to show that colony counts of Bacillus stearothermophilus spores in UHT-treated milk are influenced by the inhibitory action of the milk, so that the sporicidal effects of the UHT process as calculated from the results are too high. Only the elimination of the inhibitory factor will allow true sporicidal effects to be determined.
The interaction of bovine milk caseins with the detergent sodium dodecyl sulphate. II. The effect of detergent binding on spectral properties of caseins
Authors: Cheeseman G. C. , Knight Dorothy J. 
Published: June 2009

SummaryThe dissociation of casein aggregates by the detergent sodium dodecyl sulphate (SDS) gave rise to difference spectra and these spectra were characteristic for each of the different types of casein. Increase in absorption by the chromophore groups, tyrosine and tryptophan, when αs1- and β-casein aggregates were dissociated indicated binding of the detergent at regions of the molecule containing these residues. A decrease in absorption when κ-casein was dissociated indicated that the tyrosine and tryptophan residues were not in the region of the molecule to which the detergent was bound and that in the κ-casein aggregate these residues were in a more hydrophobic environment. Peaks on the difference spectra were obtained at 280 and 288 nm for αs1-casein and 284 and 291 nm for β-casein and troughs at 278 and 286 nm for κ-casein. The difference spectrum reached a maximum value when the αsl- and β-casein aggregates were dissociated and the further binding of SDS did not alter this value. The large negative change in the difference spectrum of κ-casein did not occur until after most of the aggregates were dissociated and did not reach a maximum until binding with SDS was complete. The value obtained for ΔOD was found to be temperature-dependent for β-casein-SDS interaction, but not for αs1- and κ-casein. Changes in spectra were also observed when αs1- and κ-casein interacted to form aggregates. The data obtained confirmed the importance of hydrophobic binding in casein aggregate formation and indicated the possible involvement of tyrosine and tryptophan residues in this binding.
The associative effect of level of energy and protein intake in the dairy cow
Authors: Gordon F. J. , Forbes T. J. 
Published: June 2009

SummaryEight lactating cows were used in a Latin square experiment, to study the associative effects of level of energy and protein intake on milk yield and composition. Four diets were used, supplying 80 and 120% of estimated energy requirements and 80 and 120% of estimated protein requirements. The level of energy intake significantly affected milk yield, milk energy output, percentage butterfat, ash and non-protein nitrogen. The level of protein intake only significantly affected milk energy output and the non-protein nitrogen content of the milk. Although only the interaction of the effects of energy and protein intake on the milk content of solidsnot-fat (SNF) and ash was significant, it was evident that the effect of each of these factors on milk yield or composition was related to the level of the other in the diet.Input-output relationships within each protein level were used to compute the response in milk energy output and bodyweight change to a change in energy intake. These showed a greater partitioning of additional energy toward milk energy output with the high than with the low protein level. Multiple regression analysis within each level of protein intake was used to partition energy intake between that used for maintenance, milk energy output and liveweight change. The results showed efficiencies of utilization of metabolizable energy for milk output of 63 and 50% on the high- and low-protein diets, respectively.Nitrogen balance data are presented.
A comparison of the milking characteristics of transparent and conventional teatcup liners
Authors: Mein G. A. , Clough P. A. , Westgarth D. R. , Thiel C. C. 
Published: June 2009

SummaryThe milking characteristics of 4 transparent and 8 conventional rubber teatcup liners in new condition were compared for peak flow rate, machine time and strip yield, using 30 cows in two 15×15 Latin squares. The milking characteristics of transparent liners were similar to those of normal liners at the same cluster weight. The 4 transparent liners were then compared with 4 of the conventional liners using 16 cows in two 8×8 Latin squares, to observe the movement of teats within the liners throughout milking. The various analyses indicated significant differences between liners but the ranked liner mean values showed the transparent liners widely distributed in the range. It was concluded that findings from studies of teatcup action using transparent liners could be expected to apply also to conventional liners.The conventional liners were selected to form groups differing mainly in one physical characteristic only (stiffness of the mouthpiece, wall thickness, bore and rubber hardness). Within groups, there were no significant differences in milking properties of practical importance, but between groups there were small differences in machine time and strip yield. Two properties of the liners which appeared important in controlling movement of the teat into the liner were bore of the barrel and friction, bore having the greater influence at the beginning and friction being the dominant influence at the end of milking. With the transparent liners it could be seen that the end of the teat was frequently bathed in milk. Both with transparent and with conventional liners it was surprising how often the teat penetrated so deeply that complete collapse of the liner in each pulsation cycle was prevented.
The effects of increasing amounts of dietary coconut oil on milk-fat secretion in the cow
Authors: Storry J. E. , Hall A. J. , Johnson V. W. 
Published: June 2009

Summary(1). A study is reported on the effects of 4 levels of coconut oil, added to a basal diet low in fat, on the secretion in cow's milk of fat and its component fatty acids. (2) A significant reduction in the yield of milk fat occurred at the highest level of supplementation. In terms of individual fatty acids the yields of lauric and myristic acids increased progressively with increased intake, maximum yields being obtained with the 7% level of coconut oil. Conversely the yields of caproic, caprylic, capric and palmitic acids progressively decreased with increased coconut oil intake. The yields of C18 acids were unchanged.