bluuebunny/crossref_metadata_2025 huggingface dataset:
STUDIES ON THE USE OF BACTERICIDAL RUBBER IN MILKING MACHINE CLUSTERS
Authors: COUSINS CHRISTINA M. , CLEGG L. F. L. , THIEL C. C. , AKAM D. N. , JONES G. ELIS , EGDELL J. W.
Published: March 2008

SUMMARY: Bactericidal rubber containing tetramethylthiuram disulphide was used in milking machine clusters cleaned by immersion in caustic soda on four farms, and by ordinary chemical sterilization on eight farms. Some reduction in the bacterial content of clusters was brought about by the bactericidal rubber, but high bacterial counts were not prevented, particularly where cleaning was inadequate. ‘Fatigue splitting’ of bactericidal rubber liners occurred after two to six weeks use.
THE STRIP TEST APPLIED TO COMMERCIAL QUATERNARY AMMONIUM COMPOUNDS. THE EFFECT OF DIFFERENT CONDITIONS
Authors: GARVIE ELLEN I.
Published: March 2008

SUMMARY: The strip test, using a minimum of four treatments, has been used to examine the suitability of quaternary ammonium compounds for use on the dairy farm. Sodium hypochlorite was the basis for comparison. None of the quaternary ammonium compounds was considered effective in the concentrations used. Two of them, both containing alkyldimethylbenzylammonium chloride, were almost as effective as sodium hypochlorite.
CAUSES OF GREENING OF UNEVISCERATED POULTRY CARCASES DURING STORAGE
Authors: BARNES ELLA M. , SHRIMPTON D. H.
Published: March 2008

SUMMARY: The greening of uneviscerated poultry carcases stored at 15° is due to the production of hydrogen sulphide following multiplication of bacteria in the gut. The main groups present in the gut after death are faecal streptococci, coli‐aerogenes organisms, lactobacilli and clostridia, but their relative importance in causing greening has not yet been established. The hydrogen sulphide diffuses from the gut into the muscle tissue and there reacts with the haem pigments of blood and muscle to form derivatives which microspectroscopically are indistinguishable from sulphaemoglobin.

The delay of greening at lower storage temperatures is consistent with this view; and it is suggested that mechanically plucked birds green more rapidly over the ribs than hand plucked ones because the shaking distributes bacteria from the caecum along the gut.
OBSERVATIONS ON THE MICROFLORA OF MINCED CHICKEN MEAT IRRADIATED WITH 4 MeV CATHODE RAYS
Authors: THORNLEY MARGARET J.
Published: March 2008

SUMMARY: Experiments are described in which minced chicken meat, packed anaerobically, was irradiated at room temperature and in the frozen state with a wide range of doses of 4 MeV cathode rays. Sterility was achieved in 14 out of 15 samples which had received 2 × 106 rads or more. Doses of 0·5 and 1·0 × 106 rads allowed survival of a few bacteria/g, usually spore formers. Bacterial counts indicated an approximately logarithmic decrease in numbers at lower doses, while freezing reduced the bactericidal effect.

The storage life at 5° was prolonged only slightly by doses of 5 × 104 and 10 × 104 rads, and highly variable results were obtained with 17·5 × 104 rads. A dose of 25 × 104 rads, however, increased the storage life very considerably. The types of bacteria present initially, and after irradiation with low doses and storage at 5°, were studied. After storage for 12 days or more various types of nonsporing Gram‐positive rods were predominant in almost all samples, both control and irradiated. Streptococci were also important where irradiation with 17·5 × 104 and 25 × 104 rads was followed by long storage.
TEMPERATURE VARIABILITY WITHIN BACTERIOLOGICAL INCUBATORS
Authors: HOSKING ZENA D.
Published: March 2008

SUMMARY: Temperature variability within four bacteriological incubators regulated for 30° has been studied using readings taken from the normal thermometers and from others placed on the incubator shelves.

During 5‐day incubation periods, differences between readings from individual thermometers and between thermometers on different shelves in the same incubator rarely exceeded 0·5° and 1° respectively. The mean temperature recorded on the top shelf was significantly higher (P <0·05) than that on the bottom shelf for all incubators, and than that indicated by the normal thermometers for two incubators.

Colony counts for pasteurized milk were not materially affected by within incubator temperature differences in this experiment nor, at three of the four centres, by removal from the incubators for brief periods for counting after intermediate incubation times.
ANAEROBIC BACILLI IN A TREATED WATER SUPPLY
Authors: WILLIS A. T.
Published: March 2008

SUMMARY: The sand from the filter‐beds of a city water supply was found to contain anaerobic bacilli and it is probable that these organisms are added to the water as it passes through, because anaerobes are present in the treated water. Emphasis is laid on the value of the anaerobe test on treated waters in assessing filter efficiency, and the significance of bacterial aftergrowth is pointed out.
THE ASSOCIATED GROWTH OF STREPTOCOCCUS LACTIS AND ESCHERICHIA COLI
Authors: HALL NITA J.
Published: March 2008

SUMMARY: The possibility that contamination of farmhouse starters by coli‐aerogenes bacteria may be a factor in producing the subtle flavour of farmhouse Cheddar cheese has been discussed. The associated growth of Strep. lactis and E. coli I at 30° and 37° resulted in the rapid disappearance of E. coli from the mixtures, even though it had been the dominant organism in some of them originally. Mixtures containing Strep. lactis and an anaerogenic strain of E. coli still contained this variant at the end of a month, although in no definite ratio and in a very much reduced proportion. It is concluded that the components of coli‐lactic starters to be used in the manufacture of cheese should be combined together in the vats.
A PROPERTY OF OX MUSCLE AFFECTING BACTERIAL GROWTH AT 0°
Authors: BROWN A. D. , COOTE G. G. , MEANEY M. F.
Published: March 2008

SUMMARY: Increases occurring in bacterial populations at 0° were followed on minced preparations of two selected muscles of beef cattle which had been exposed to various treatments before death. In one muscle (Psoas), bacterial growth increased with increase in pH while in the other (Longissimus dorsi) it decreased with increase in the time elapsing prior to onset of rigor mortis. This second relationship could not be observed in the Longissimus dorsi of cows. The nature of the property responsible for the effects of rigor delay time in the Longissimus dorsi of steers has not yet been established.
A SIMPLIFIED METHOD FOR THE PREPARATION OF EGG YOLK MEDIA
Authors: BILLING EVE , LUCKHURST E. R.
Published: March 2008

SUMMARY: Difficulties with filtration in the preparation of egg yolk media were overcome by preparing the yolk emulsion with distilled water instead of saline. The turbidity of the final medium was related to its sodium chloride content.
A METHOD FOR THE CULTIVATION OF ANAEROBIC SPORE FORMING BACTERIA
Authors: KNETEMAN A.
Published: March 2008

SUMMARY: A method is described for the cultivation of anaerobes based upon the following two principles: (1) Anaerobiosis is achieved by the addition of an aerobic micrococcus to the nutrient medium itself. After anaerobiosis has been achieved the micrococcus gradually dies, leaving the anaerobes in a pure state. (2) In the plate technique it is necessary to prevent diffusion of oxygen from the air into the medium. This is effected by covering the agar with a film of Saran which is impervious to oxygen. The plate method is carried out in ordinary Petri dishes: anaerobic jars are not used.
COLI‐AEROGENES BACTERIA FROM FARM DAIRY EQUIPMENT AND RAW MILK
Authors: THOMAS S. B. , HOBSON PHYLLIS M. , ELSON K.
Published: March 2008

SUMMARY: A series of 1,040 cultures of coli‐aerogenes bacteria isolated at 30° from farm dairy equipment and raw milk was classified according to the recommendations of the Coliform Sub‐Committee of the Society for Applied Bacteriology (Report, 1949). The distribution of species and types isolated from milk did not differ materially from that for dairy equipment, Klebsiella cloacae, K. aerogenes and Citrobacter freundii being the dominant species, while the incidence of Escherichia coli was relatively low. There was no marked seasonal incidence of any type, though E. coli I formed a slightly higher proportion of the coli‐aerogenes microflora in winter, whereas K. aerogenes I was slightly higher in summer. Many of the cultures of the dominant types, K. cloacae, K. aerogenes I and Cit. freundii I, did not form acid and gas from lactose in two days at 37°. Consequently 37° negative, anaerogenic and paracolon strains constituted a relatively high proporton (49%) of the coli‐aerogenes microflora.
A SELECTIVE MEDIUM FOR BACILLUS CEREUS IN MILK
Authors: DONOVAN KATHLEEN O.
Published: March 2008

SUMMARY: A medium is described by means of which cells of Bacillus cereus in milk may be estimated without the prior use of a heat treatment. Into a nutrient agar are incorporated: egg yolk, to demonstrate production of the characteristic opacity; citrate, to render the inoculated medium more transparent; lithium chloride and polymyxin, to reduce the growth of other bacteria. A cover of water agar limits the development of certain spreading organisms. The medium has proved of value in a survey of samples of raw milk, providing information additional to that obtained by plating after a heat treatment.
EXOCELLULAR PRODUCT FORMATION BY MICROORGANISMS IN CONTINUOUS CULTURE. I. PRODUCTION OF 2:3‐BUTANEDIOL BY AEROBACTER AEROGENES IN A SINGLE STAGE PROCESS
Authors: PIRT S. J. , CALLOW D. S.
Published: March 2008

SUMMARY: A quantitative study of the growth and carbohydrate metabolism of Aerobacter aerogenes in continuous culture with particular reference to 2:3‐butanediol production is described. The effects of varying dilution rate, oxygen uptake rate, pH value, temperature and CO2 pressure were studied.

The optimum pH value was 5·0°6·0. The optimum temperature was 35–37° with a dilution rate of 0·2 hr−1. The rate of sugar metabolism was decreased by raising the CO2 pressure.

In continuous culture the maximum diol output rate/1. of working volume exceeded the greatest rate reported for batch culture by a factor of three. The maximum diol concentration and yield as a percentage of the theoretical maximum were lower in continuous culture than in batch culture. Reasons for this are given.

Some variants of the parent organism were found in continuous cultures but they caused no change in the yield of butanediol. There was no sign of loss of butanediol‐producing ability by any of the cultures, some of which were maintained for 2,000 hr. For the first few generations the rate of production of butanediol actually increased.
THE POTASSIUM UPTAKE OF LACTOBACILLUS ACIDOPHILUS
Authors: HARRIS N. O.
Published: March 2008

SUMMARY: A reproducible flame speetrophotometric method for the determination of the potassium uptake of Lactobacilius acidophilus is described. The potassium uptake curve was characteristic and had a coefficient of variation between replicate samples at peak uptake of approximately 2%. Two general applications of the technique have been demonstrated: the evaluation of the toxicity of an inhibitory substance (fluoride as sodium fluoride), and determination of the effect of the interaction of L. acidophilus and L. casei in a mixed culture.
A SURFACE FILM METHOD OF EVALUATING QUATERNARY AMMONIUM COMPOUNDS
Authors: WHITT EUNICE W.
Published: March 2008

SUMMARY: A suspension of bacteria was evenly spread on descaled stainless steel strips and air dried. The strips were put into the QAC solution and after the required period the bactericidal action was stopped by adding a neutralizing agent. The strips were covered with nutrient agar and incubated at 37° for 24 hr to enable the surviving organisms to grow into colonies. On removing the thin layers of agar from the strips the colonies were left adhering to the metal. They were stained with carbol fuchsin and counted using a dissecting microscope.

Using the recommended strength of a QAC‐detergent solution (200 p/m QAC) and an exposure time of 2 min a mortality of at least 99·58% was obtained. The temperature of treatment had little effect on this, though in experiments with added organic matter or lower concentrations of QAC the temperature was important.
THE FORMATION OF GENTIOBIOSE AND OTHER SACCHARIDES DURING PRESSURE‐STEAM STERILIZATION OF A GLUCOSE‐SALTS SOLUTION OF pH 6.8
Authors: KHAN A. W. , WALKER T. K.
Published: March 2008

SUMMARY: Two samples of glucose of high quality were examined chromatographically for impurities in the form of saccharides other than glucose. One contained gentiobiose and at least three other sugars amounting to 35 mg/100 g of glucose; the other contained gentiobiose and at least four other sugars, the total quantity being 25 mg/100 g of glucose. Glucose from which these small quantities of impurities had been removed was employed, together with inorganic salts, to make up a medium suitable for the cultivation of moulds and the pH value was adjusted to 6·8. This medium was sterilized at 10 lb pressure for 15 min and it was afterwards found that a mixture of saccharides amounting to 125 mg/100 g of glucose had been formed, the principal constituent being gentiobiose; the remainder consisted of a monosaccharide and two oligosaccharides not yet identified. These sugars were not detected in similar glucose salts media which had not been heated but which had been sterilized by Seitz fitration.
THE HEAT RESISTANCE OF ESCHERICHIA COLI CELLS FROM CULTURES OF DIFFERENT AGES
Authors: LEMCKE RUTH M. , WHITE HELEN R.
Published: March 2008

SUMMARY: From the mortality curves of Escherichia coli cells heated at 55° in Ringer's solution both Decimal Reduction Times (DRTs) and 99–9% mortality times were obtained. In terms of these measures of heat resistance, cells harvested from broth cultures 0–8 hr old were more susceptible than those from more mature cultures. The time of commencement and the approximate duration of the logarithmic phase of growth of the organism in broth were determined from growth curves, and it was observed that the heat resistance was minimal during that phase.

Death rates were not always uniform for the whole of a given population. Particularly among young cultures, a period of rapid death was frequently followed by the slower death of a relatively small number of survivors. In one instance only was an initial period of slow death followed by one of more rapid death.
THE BACTERIOLOGY OF THE ROOT REGION OF THE OAT PLANT GROWN UNDER CONTROLLED POT CULTURE CONDITIONS
Authors: LOUW H. A. , WEBLEY D. M.
Published: March 2008

SUMMARY: The bacteriology of the root region of oat plants grown under controlled conditions has been studied by means of improved techniques for separate estimation of the microfloras of the rhizosphere soil and of the root surface. The plate count of bacteria in the root region increased during the growing period of the plants; superphosphate produced a greater increase, which was probably due to increased plant growth, as no such effect was observed in uncropped soil.

The numbers of acid producing and dicalcium phosphate dissolving bacteria were increased in the root region, but the latter were not preferentially stimulated. Dressings of superphosphate and dicalcium phosphate also did not preferentially stimulate either group. No evidence was obtained, by the plate method used, of the presence of organisms capable of dissolving variscite, strengite, or gafsa rock phosphate, although the plants showed appreciable response to gafsa rock phosphate.
COMPARISONS OF DIFFERENT MEDIA FOR COUNTING SUGAR TOLERANT YEASTS IN CONCENTRATED ORANGE JUICE
Authors: INGRAM M.
Published: March 2008

SUMMARY: To select and count the sugar tolerant yeasts which ferment sixfold concentrated orange juice, a high sugar agar medium was developed which contains 50% of glucose, 1% of citric acid and 1% of Tryptone; it is incubated for 4–5 days at 25°.

The medium has disadvantages: it is troublesome to prepare, and colonies grow slowly and are translucent. These properties result directly' from the high sugar concentration, on which the selective action of the medium depends.

Counts on this medium have been compared with those on potato dextrose or nutrient dextrose agars (with 2% and 1% of glucose respectively), with yeasts isolated from fermenting concentrate, in pure culture, and under various practical conditions. As a rule, the counts were virtually the same on the different media; nutrient dextrose agar occasionally failed to record small numbers of these yeasts. If the two low sugar media were acidified to pH 3·5 the counts were reduced.

Potato dextrose agar recorded, besides the above yeasts, sugar intolerant yeasts entering from dirty machines or through bad canning practice: nutrient dextrose agar recorded bacteria in addition. The difference between parallel plating on these media and on the high sugar medium thus yielded useful information about sources of casual contamination.

It is suggested that the above would also be largely applicable to other sugar‐rich concentrates of not less than 50° Brix.
A NOTE ON THE SOURCE AND IDENTIFICATION OF THE STRAINS OF HETEROFERMENTATIVE LACTOBACILLI SUBMITTED TO CHROMATOGRAPHIC ANALYSIS
Authors: Sharpe M. Elisabeth
Published: March 2008

SUMMARY: The examination of 91 strains of heterofermentative lactobacilli and the subdivision of the groups by the chromatographic patterns is described. The overall assessment of differences suggests that division is arbitrary; however, selection of certain characters has produced a division which is in agreement with the previous biochemical grouping.
THE VALUE OF THE ASSOCIATION ESCHERICHIEAE‐GROUP D STREPTOCOCCI IN THE DIAGNOSIS OF CONTAMINATION IN FOODS
Authors: BUTTIAUX R.
Published: March 2008

SUMMARY: The tests for faecal contamination in foods, based on ‘indicator species’, should be reconsidered for the following reasons. First, in Europe, Escherichia coli is regarded as a specific index of such contamination; but, apparently through the use of antibiotics, the proportion of human faeces containing Klebsiella has risen from 5.2% in 1947 to 48.4% in 1956–7. Moreover, E. coli and other coli‐aerogenes organisms may be absent from the gut of certain animals, notably the pig. Second, while the usual methods of counting coli‐aerogenes bacteria do not permit the isolation of strains which ferment lactose slowly or not at all (i.e. paracolons), these occur in 35.6% of samples of human faeces. Further, the recommended methods of detecting such strains are not wholly satisfactory. Third, the origin of the coli‐aerogenes bacteria is uncertain.

It is thus necessary to consider other organisms which normally inhabit the intestinal tract of humans and other animals. As to Clostridium perfringens, its source is doubtful, for it may come from faeces or from soil, and many foods contain only soil strains. The group D streptococci, on the other hand, are excellent indicators of faecal contamination. They are constant or frequent in the intestines of man and animals, and often more numerous there than coli‐aerogenes bacteria. Their specificity as an index of faecal contamination is high and their investigation is easy with the selective media now available. Associated with the coli‐aerogenes bacteria, they justify the diagnosis of faecal contamination in a foodstuff.
THE DIFFERENTIATION OF PSEUDOMONAS FROM OTHER GRAM‐NEGATIVE BACTERIA ON THE BASIS OF ARGININE METABOLISM
Authors: THORNLEY MARGARET J.
Published: March 2008

SUMMARY: Of 391 Gram‐negative bacteria isolated from chicken meat spoiled at a low temperature and classified by the commonly used methods, 156 were considered to be Pseudomonas and 188 Achromobacter, and 47 others belonged to the coli‐aerogenes group or remained unclassified. A test for the production of alkaline conditions in an arginine medium incubated under a vaseline seal gave positive results for 155 of the Pseudomonas isolates, and negative results for 1 Pseudomonas and all the 188 Achromobacter strains. When named strains from culture collections were tested under these conditions, 63 Pseudomonas strains produced alkalinity while two plant pathogenic Pseudomonas species and two non‐pigmented strains did not. These last two, which produced no acid from glucose, could not be regarded as typical Pseudomonas. All the Achromobacter strains gave negative results, as did four Alcaligenes, but one species, Alcaligenes bookeri, produced slightly alkaline conditions. One strain of Chromobacterium and three of Vibrio were also positive. These could be distinguished from Pseudomonas by their metabolism of glucose.
THE BEHAVIOUR OF INDIVIDUAL ORGANISMS IN THE LAG PHASE AND THE FORMATION OF SMALL POPULATIONS OFESCHERICHIA COLI
Authors: QUESNEL L. B.
Published: March 2008

SUMMARY:The generation times of individualEscherichia colicells inoculated on to a cellophane membrane and supplied with a liquid synthetic medium were determined by direct observation for four generations. Viability increased and generation time decreased with increasing age of population.
A COMBINED TEST FOR PENICILLINASE PRODUCTION AND PENICILLIN SENSITIVITY OF STAPHYLOCOCCI
Authors: INNES A. G.
Published: March 2008

SUMMARY: A method described for the demonstration of penicillinase production by staphylococci, a modification of that described by Voureka & Hughes (1949), is less laborious than the original and gives results which are readily interpreted.
THE ACTION OF NISIN ON SPOILAGE BACTERIA. I. THE EFFECT OF NISIN ON THE HEAT RESISTANCE OF BACILLUS STEAROTHERMOPHILUS SPORES
Authors: THORPE R. H.
Published: March 2008

SUMMARY: Spores of two strains of Bacillus stearothermophilus were heated for various times both in the absence and presence of nisin and in the latter case both with and without subsequent destruction of the nisin with trypsin. The results obtained on enumeration of the survivors indicated that the reduction of heat resistance which was observed was apparent rather than real and was due to the adsorption of nisin on the spores. When this was removed by means of trypsin the heat resistance was restored almost to normal.
MICROBIAL SULPHIDE PRODUCTION FROM SULPHATE‐ENRICHED SEWAGE SLUDGE
Authors: BUTLIN K. R. , SELWYN SYLVIA C. , WAKERLEY D. S.
Published: March 2008

A laboratory process for the microbial production of sulphide from sewage sludge enriched with sulphate has been further developed. Semicontinuous fermentations yielded 0·9–1·0% S2‐ using a 10‐day replacement time (RT) and 0·8% S2‐ with a 5‐day RT. Yields at 37° were slightly higher than at 30°; at 43° and above yields were much lower. A mixture of 70% N2 and 30% CO2 was successfully used as sweeping gas to remove H2S; other proportions of these gases were less efficient. Stripping H2S from the sludge in an external column was as efficient as passing the stripping gas through the bulk of the fermenting sludge.
AN ECOLOGICAL STUDY OF THE COLI‐AEROGENES BACTERIA OF SURFACE SOIL
Authors: THOMAS S. B. , DRUCE R. G. , ELSON K.
Published: March 2008

The coli‐aerogenes organisms content, determined by plating on violet red‐bile agar, of surface soil from a polluted site (heavily grazed pasture) often exceeded 104/g at 30° and 103/g at 37°. Escherichia coli I was present but in a small proportion only. High coli‐aerogenes counts were much less frequent in unpolluted soil (enclosed Forestry Plantation), and E. coli I was relatively rare. The classification of 1,917 strains isolated from colonies on VRB agar at 30° and at 37° showed that Klebsiella cloacae was very much the dominant species in both sites when the plates were incubated at 30°, whereas Citrobacter freundii I and K. cloacae were co‐dominant when incubation was at 37°. E. coli II constituted a relatively high proportion of the strains from both sites but, due to the very marked dominance of these three types, E. coli I was rarely isolated by the method employed, even from the polluted soil. The very high incidence of non‐lactose‐fermenters, particularly among the dominant types, was the outstanding characteristic of the strains isolated, even with incubation at 37°. Only 29% formed acid and gas in MacConkey's broth within 2 days at 37°, while 59% formed acid and gas within 5 days at 30° but failed to do so in 2 days at 37°. There was a much higher incidence of coli‐aerogenes organisms in soil from the unpolluted site during summer than during winter, and this is attributed to possible multiplication of 37° negative strains of the more common types.
THE DIFFERENTIATION OF BACTERIAL SPECIES BY PAPER CHROMATOGRAPHY. IX. THE GENUS BACILLUS: A PRELIMINARY INVESTIGATION
Authors: JAYNE‐WILLIAMS D. J. , CHEESEMAN G. C.
Published: March 2008

A preliminary survey of species of the genus Bacillus has shown that the comparative study of the bacterial amino pool, using paper partition chromatography techniques, shows promise as an aid to differentiation. But special factors, such as sporulation and other growth characteristics, make the use of these techniques more complicated than is the case with some other genera.

Seventy‐five mesophilic strains were examined and in general the chromatogram patterns correlated well with the biochemical, morphological and cultural characters. Further, it appears that these chromatographic techniques could be applied with advantage in the study of spore germination, heat activation and sporulation, and of the influence of growth medium, pH, temperature and degree of aeration on the metabolism of micro‐organisms. The taxonomy of the thermophilic sporeformers and of new species would be clarified by chromatographic studies.
FAT SYNTHESIS BY YEASTS. I. A COMPARATIVE ASSESSMENT OF HANSENULA SPECIES
Authors: HOPTON J. W. , WOODBINE M.
Published: March 2008

A comparative examination of the growth of 15 species of Hansenula in typical ‘fat’ media has been undertaken. Seven species showed a good yield on the basis of sugar consumed and, in terms of fat content, they fell into three broad categories. H. ciferrii and H. saturnus had a fat content (c. 20%) rather lower than that of Rhodotorula gracilis grown under the same conditions; 2 strains of H. anomala had a fat content of about 13%, and H. jadinii, H. angusta and H. subpelliculosa had a relatively low fat content (c. 8%). In a ‘fat’ medium containing urea as principal nitrogen source there was an initial phase during which most of the nitrogen was assimilated, followed by a phase during which most of the fat accretion occurred.
THE BACTERIOLOGY OF DISTANT WATER COD LANDED AT HULL
Authors: SPENCER R.
Published: March 2008

Plate counts at 20° on the skin and flesh of distant water cod landed at Hull were within the ranges 4·2 × 103–3°6 × 107/cm2 and 2·3 × 103–2·4 × 106/g, respectively, with median values of approximately 106/cm2 and 105/g. The counts at 37° were considerably lower. A light but general contamination of the fish with Escherichia coli I and the presence of occasional coagulase positive staphylococci were observed. Organisms of the salmonella‐shigella groups were not detected. Pseudomonas and Achromobacter were the dominant genera and formed from 4% to 84%, and 3% to 65% of the total flora, respectively. Corynebacteria were usually present and in one case constituted 50% of the flesh flora. The significance of these findings in relation to proposed bacteriological standards for cleanliness of perishable foods and to the spoilage of fish is discussed.
FURTHER STUDIES ON THE DISINFECTION OF COWS’ TEATS PRIOR TO MILKING
Authors: McKENZIE D. A. , HUNTER A. C.
Published: March 2008

A comparison has been made of the disinfecting efficiency on cows' teats of a hypochlorite and a quaternary ammonium disinfectant. Little difference in efficiency was found between the disinfectants when used at 200 p/m. Hypochlorite was slightly more effective in eliminating coli‐aerogenes bacteria, but there was no evidence of greater survival of other Gram‐negative organisms with the quaternary disinfectant. Micrococci were the main survivors and, in summer, coagulase positive staphylococci formed a considerable proportion of these.
SOME PHENOL DECOMPOSING STRAINS OF PSEUDOMONAS
Authors: DAVEY B. B. , TURNER And MYFANWY
Published: March 2008

Three strains of Pseudomonas Migula, capable of utilizing phenol and other aromatic compounds as sole sources of carbon, are described. They resemble certain strains of Ps. aeruginosa and P. fluorescens except in this ability.
THE LECITHINASE AND LIPASE ACTIVITIES OF MEMBERS OF THE GENUS PSEUDOMONAS
Authors: HOBBS G. , GOWLAND G. , WILLIS A. T.
Published: March 2008

The group I pseudomonads of Shewan, Hobbs & Hodgkiss (1960) generally produced both lipase and lecithinase, the species Pseudomonas aeruginosa being consistently active. Strains belonging to the other three groups were comparatively inactive.
THE STERILIZATION OF GOAT SKIN WITH ETHYLENE OXIDE AND SOME BACTERIOLOGICAL STUDIES OF THE PROCESS
Authors: SEN S. N.
Published: March 2008

Because it is uncertain whether the usual methods of sterilizing leave the normal structural characteristics of hide and skin unaltered, studies are usually made on hide powder and the results so obtained extended to hide and skin. The results of such studies, however, sometimes prove confusing and the conclusions drawn may be false.

In the present investigation skins were so treated with ethylene oxide as to render them bacteriologically sterile and the influence of any residual effect on the activities of bacteria subsequently cultured on the skins was studied from different aspects.
THE MICROFLORA OF THE RUMEN OF THE YOUNG CALF: II. SOURCE, NATURE AND DEVELOPMENT
Authors: ZIOLECKI A. , BRIGGS C. A. E.
Published: March 2008

Twelve calves of different sex and breed divided into four groups were used in the experiments. Each group received different rearing and diet treatment. Three hundred and nine samples of rumen contents were obtained by means of a stomach tube during the period from birth to three months of age. Streptococci, lactobacilli and coli‐aerogenes organisms were isolated and studied, and isolates were also made from various elements of the calves’ environment.

Rapid development of the rumen flora occurred immediately after birth of the animals. During the first week of life, streptococci and coli‐aerogenes organisms predominated, whereas no lactobacilli were isolated from calves on any of the treatments. The coliaerogenes count (107‐108/g wet weight) was higher than in the adult rumen, but dropped to its normal level during the succeeding two weeks. The streptococcus and lactobacillus counts varied according to treatment.

Streptococcus bovis was the predominating streptococcal species, except during the first week of life, when Strep. faecium predominated and Strep. bovis amounted to only 28·6% of the total streptococcal isolates. The variation in physiological characteristics within the Strep. bovis strains was greater than normally found within strains from adult cattle. Lactobacillus acidophilus, L. plantarum and a group of strains which resembled L. brevis predominated among the lactobacilli. Most of the coli‐aerogenes organisms were Escherichia coli, faecal type I.

The diet was found to influence the proportion of streptococci and lactobacilli in the rumen, whereas the incidence of various species of the two groups of bacteria, particularly the streptococci, was associated with the age of the animals.

The microflora of the environment influenced the rumen flora only during its early development, soon after birth of the calves.
THE EFFECT OF MODIFICATIONS IN THE COUNTING MEDIUM ON THE VIABILITY AND GROWTH OF BACTERIA DAMAGED BY PHENOLS
Authors: JACOBS S. E. , HARRIS N. D.
Published: March 2008

Bacteriological agar has been shown to be toxic towards Escherichia coli and Staphylococcus aureus. The effect was observed when nutrient agar was treated with Norit or ferric chloride and when the agar component alone was treated similarly. With both agents, larger colonies from untreated suspensions of Staph. aureus and higher counts from phenol treated suspensions of both species, were produced. Aluminium and chromium gave effects similar to those of iron, but iron gave the largest colonies of Staph. aureus. Magnesium also was especially successful in inducing high counts of damaged cells.

A batch of Japanese agar, although apparently of poor quality, was superior by both the above criteria to two batches of New Zealand agar; but all three batches of agar were toxic to some degree.
A NEW TEST FOR THE DETECTION OF BACTERICIDAL ACTIVITY USING AGAR ‘REPLICATES’
Authors: PARRY JOY
Published: March 2008

A quick method is described which may be used for testing the bactericidal activity of compounds in solution or in formulation and is particularly useful for examining antiseptic creams. It is based upon making impressions or ‘replicates’ by agar to agar contact.
MICROSCOPICAL OBSERVATIONS ON THE EMERGENCE OF CELLS OF BACILLUS SPP. FROM SPORES UNDER DIFFERENT CULTURAL CONDITIONS
Authors: GOULD G. W.
Published: March 2008

Spores of Bacillus spp. germinate in suitable environments prior to shedding their outer walls or spore coats. The effects of environmental factors on the way in which spore coats open have been studied. These have included temperature, pH, availability of metals, salt concentration, the presence of coat‐lytic enzymes and the effect of preheating the spores.

Generally, spores of large celled species leave behind ill defined structures probably because they dissolve their coats. Spores of small celled organisms leave behind well defined coats after the new vegetative cells have emerged and different strains and species open their coats in a number of different ways. Of the cultural changes, only the pH of the medium markedly affected the mechanism of coat opening. Low pH reduced the extent to which large spores lyzed their coats, and altered the type of coat opening typical of spores of certain small celled species.
THE INCIDENCE OF LECITHINASE POSITIVE CLOSTRIDIUM WELCHII IN THE PIG AND THE EFFECTS THEREON OF ANTIBIOTIC FEED SUPPLEMENTS
Authors: ANDRLA O. , BRIGGS C. A. E.
Published: March 2008

The varying incidence of Clostridium welchii in the gut of growing pigs, and the suppression of these organisms on addition to the diet of nutritional levels (50 g/ton) of antibiotics, have been demonstrated. The degree of lecithinase activity of the organisms and administration of antibiotics were correlated. Growth stimulation was not demonstrable in older pigs, though antibiotic feed supplements may have some prophylactic value for such animals.
A SIMPLIFIED METHOD FOR THE MEASUREMENT OF BACTERIAL SURFACE CONTAMINATION IN FOOD PLANTS AND ITS USE IN THE EVALUATION OF PRESSURE CLEANERS
Authors: HANSEN N.‐H.
Published: March 2008

A new rapid method 1 for determining microbial surface contamination has been developed. Samples are taken with cotton swabs and transferred directly to agar slants. The slants are grouped according to the number of colonies formed during incubation, and the average number of colonies and its standard deviation are determined by plotting the distribution on probability paper. The method, which is particularly well suited for large scale field examinations, was used to evaluate the efficiency of hydraulic pressure cleaners in a pig slaughterhouse. As a result of the daily use of the pressure cleaners, the bacterial surface contamination on the machinery and equipment was in no place higher than about 100/cm2 after cleaning. Further, there was a 90% reduction of the surface counts on the dressed pig carcases. Also, the cleaning was more rapidly done than by the traditional methods.
THE ISOLATION OF ANAEROBIC GRAM‐NEGATIVE BACTERIA FROM POULTRY REARED WITH AND WITHOUT ANTIBIOTIC SUPPLEMENTS
Authors: BARNES ELLA M. , GOLDBERG H. S.
Published: March 2008

A number of methods advocated for the isolation of ‘bacteroides’ have been tested. By using an ethyl violet–azide agar medium under strictly anaerobic conditions, as many as 108/g of a group of obligately anaerobic Gram‐negative bacteria were detected in the caeca of chickens. Freshly isolated organisms from chlortetracycline fed chickens showed a slightly greater resistance to chlortetracycline than those isolated from the control birds, but there was little difference after further subculture.
THE ‘VACUUM PACK’ METHOD OF PACKAGING FOODS IN RELATION TO THE FORMATION OF THE BOTULINUM AND STAPHYLOCOCCAL TOXINS
Authors: THATCHER F. S. , ROBINSON J. , ERDMAN I.
Published: March 2008

The development of botulinum toxin in smoked fish and of staphylococcal enterotoxin in packed bacon has been demonstrated. It is to be expected that these toxins may be produced in contaminated commercial products stored under conditions which permit substantial growth of the organisms, though formation of enterotoxin is not a predictable sequel to multiplication of staphylococci.
THE BACTERIAL FLORA OF PUGET SOUND FISH
Authors: COLWELL RITA R.
Published: March 2008

Several species of marine fish were sampled bacteriologically to determine the bacterial types associated with the skin, gills, gut and mouth of the animals. Analysis of the total sample distribution of 311 pure cultures showed that Pseudomonas species composed 44–48% of the floras of all the areas except the mouth, where they comprised 68% of the flora, and Achromobacter and Micrococcus made up about 17% and 6%, respectively, of the floras from the several sites. A pleomorphic, coccoid, fermentative Vibrio type was found in greatest numbers in the gut, although it was present on the gills and, less frequently, on the skin. The biochemical and physiological characteristics of the organisms isolated suggest that detectable differences exist among the bacterial populations from the skin, gills, gut and mouth. Fish caught in the water of Puget Sound by hand line, deep water otter trawl, inshore otter trawl, beach seine and purse seine were examined bacteriologically to determine the effects of catching method on the qualitative distribution of types, and 299 pure cultures were isolated and extensively tested. The hand line samples yielded a flora consisting predominantly of Pseudomonas and Achromobacter, though Micrococcus and Flavobacterium were present in significant numbers. Some differences were observed between the bacterial populations of the fish captured by the other methods, particularly in the presence of Bacillus and Corynebacterium and of miscellaneous types. These differences, in general, could be attributed to the catching operation.
THE DISTRIBUTION OF GROUP D STREPTOCOCCI IN CATTLE AND SHEEP
Authors: MEDREK T. F. , BARNES ELLA M.
Published: March 2008

Numbers and types of Lancefield group D streptococci have been determined in samples from the colons of 17 cattle and 9 sheep. Mean total streptococcal counts of 8 × 104/g in cattle and 2 × 106/g in sheep were obtained. Streptococcus bovis was found in every sample and was the predominant species in 15 of the cattle and 6 of the sheep. Other group D streptococci (Strep. faecalis, Strep. faecium and Strep. durans) were rare in cattle, but in sheep they formed a significant proportion of the population. Of 60 Strep. faecium, Strep. durans and related strains, 51 fermented raffinose. Many of the strains of Strep. faecium were also atypical in that they fermented sorbitol and appreciably reduced tetrazolium in broth at pH 6.0.

Strep. bovis remained the predominant streptococcus in faeces samples from 4 dairy cows when they were tested again after an interval of 17 and 18 months.
THE DIRECTED ISOLATION OF MUTANTS PRODUCING INCREASED AMOUNTS OF METABOLITES
Authors: SCHERR G. H. , M. E. RAFELSON (Jr.)
Published: March 2008

A method is described whereby mutants having a directed increased yield of a metabolite may readily be isolated. A culture of bacterial cells is exposed to a gradient concentration of an antimetabolite that is inhibitory to the growth of the organism and mutants are isolated which survive because of an increased yield of the metabolite. This increased yield may be several times that formed by the parent culture. Techniques and results for increasing the yields of pyridoxine, nicotinic acid and thiamine are described.
SPORULATION AND THE DEVELOPMENT OF RESISTANCE IN SPORING CULTURES OF CLOSTRIDIUM WELCHII
Authors: CASH J. D. , COLLEE J. G.
Published: March 2008

The growth of a strain of Clostridium welchii type A in Ellner's medium was studied and the development of spores was correlated with the emergence of forms resistant to deleterious influences including heat, desiccation and thiomersalate. A qualitative increase in heat resistance was demonstrated, coincident with spore maturation over the course of 12 hr. The granular appearance of the bacterial cytoplasm prior to sporulation, as revealed by Gram's stain, precedes the development of acid‐fast material and does not seem to be associated with the presence of sudanophilic or metachromatic material.
THE RETENTION OF 32P‐LABELLED RHIZOBIUM BY LEGUME SEED AFTER INOCULATION BY VACUUM TREATMENT
Authors: COOPER R.
Published: March 2008

Legume seeds were vacuum treated in a suspension of 32P‐labelled Rhizobium meliloti to find the numbers and uniformity of distribution of bacteria taken up and retained by the seeds after washing. Commercial seed retained 5–12 times as many bacteria as did hand harvested seed. From 5 to 15% of the seeds held 75–90% of the bacteria; vacuum treatment increased uptake by this small group of seeds by 60–300%, but had no significant effect on the majority that acquired relatively few bacteria. Therefore vacuum treatment of seeds during inoculation is likely to affect nodulation on a small proportion of the plants only.
Bacterial Sulphate Reduction and the Development of Alkalinity. I. Experiments with Synthetic Media
Authors: Abd‐el‐Malek Y. , Rizk S. G.
Published: March 2008

In liquid cultures of Desulphovibrio desulphuricans the effects of the following on sulphate reduction were determined: the type of cation (Ca++ or Na+) attached to the sulphate ion; the presence of calcium carbonate alone and with sodium chloride; the concentration of sodium sulphate, sodium lactate and sodium chloride; and the initial pH. The titratable alkalinity formed as a result of sulphate reduction was found to be quantitatively related to the sulphate reduced, and apparently unaffected by strain variation or energy source.
Bacterial Sulphate Reduction and the Development of Alkalinity. III. Experiments under Natural Conditions in the Wadi Natrûn
Authors: Abd‐el‐Malek Y. , Rizk S. G.
Published: March 2008

Evidence that microbial sulphate reduction is mainly responsible for the formation of the natron (hydrated Na2CO3) deposits in Wadi Natrûn is presented. The sulphate in the infiltrating water is reduced during passage through the surrounding waterlogged soil and the bicarbonate formed is later concentrated by evaporation in the lakes.
Characteristics of Erwinia‐like Organisms found in Plant Material
Authors: Billing Eve , Baker Lily A. E.
Published: March 2008

The characters of 20 nonpigmented and 2 yellow pigmented isolates of Ervinia‐like organisms from plant material (primarily pome fruit) are described and compared with those of Erwinia amylovora. Cultures of some other Erwinia species were also included in the study for comparison. It is suggested, on the basis of their similarity to Erw. amylovora, that they should be included in the genus Erwinia, although they have no obvious pathogenic role. The relationship of these organisms with Erw. lathyri and Bacterium herbicola is discussed.
A Replica Plate Culture Technique
Authors: Harris P. J.
Published: March 2008

A replica plating technique is described in which cultures are grown on individual agar discs in a Petri dish. Products of metabolism are confined to the discs and colony spreading is restricted.
Preventing Temperature Rise during the Mechanical Breakage of Micro‐Organisms
Authors: Chelton E. T. J.
Published: March 2008

Summary: Experiments have shown that there is a considerable increase in temperature during the mechanical breakage of micro‐organisms when using a Mickle tissue disintegrator and a vibratory ball mill. Simple enclosures containing solid CO2 are described by means of which rise in temperature during treatment may be prevented.
Sulphamic Acid as a Nitrogen Source for Micro‐organisms
Authors: Jensen H. L.
Published: March 2008

Summary: The ability of micro‐organisms to use sulphamic acid in the form of the sodium salt as a source of nitrogen appeared to be generally uncommon, but certain strains of Aureobasidium (Pullularia) pullulans and Cephalosporium acremonium (?), and also two unidentified species of Achromobacter and Flavobacterium, were found to do so.

A. pullulans utilized ammonium and sulphamate nitrogen equally well, but growth with sulphamate did not become vigorous until after a long period of induction, even though the inoculum was produced on a sulphamate medium. The fungi as well as the bacteria converted the sulphur of the sulphamate ion to sulphate in approximately equimolar proportion to the amount of assimilated nitrogen.

Sulphamate utilizing strains of A. pullulans were found widely distributed on autumn leaf material but much less so in soil.
The Effect of Relative Humidity and Light on Air‐Dried Organisms
Authors: Webb S. J.
Published: March 2008

Summary: The effect of relative humidity (RH) and inositol on the lethal action of artificial sunlight has been studied. The lethality of these radiations is shown to be strongly dependent on RH provided the intensity of the light is not too great. A critical region between 55 and 65% RH exists in which there is an abrupt change in the sensitivity of airborne cells to all wavelengths tested. Not only does the death rate change suddenly in this RH region but so also does the rate of mutant production. This critical RH region corresponds to the RH level at which bound water is removed from the nucleic acid bases and it is suggested that these water molecules are able to prevent lethal excitations or migration of excitation energy. Inositol is shown to prevent radiation damage and, because of its structure, it is assumed to replace water in the dried cells. Some ramifications of these findings with respect to the maintenance of cell integrity are discussed.
The Survival of Starter Organisms in Concentrated Suspensions
Authors: Lamprech E. D. , Foster E. M.
Published: March 2008

Summary: Two representative lactic acid bacteria were grown in a rich organic medium, the cells were harvested by centrifugation, and the organisms were suspended in skimmilk at concentrations of 25–55 × 109/ml. The pH was adjusted to different values and the suspensions were stored, with and without the addition of 20% (v/v) glycerol, at 4° and ‐ 20°.

Both organisms survived better at pH 7°0 than at pH 5°0. Glycerol protected the cells at the lower pH value but offered no benefit at neutrality. At 4° about half the cells died within 5 or 6 weeks. At ‐ 20°, however, there was no appreciable loss of viability or acid producing ability up to 9 months at pH 7°0. Suspensions stored for 9 months at ‐ 20° produced excellent cultured buttermilk within the normal incubation period from an inoculum comparable to that used for a fresh culture. Cells harvested early in the maximum stationary phase of the growth cycle were more active than older cells, and they survived better than older cells during storage in the frozen state.