bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluctuations in Escherichia coli O‐serotypes in Pigs Throughout Life in the Presence and Absence of Antibiotic Treatment
Authors: LINTON A. H. , HANDLEY BARBARA , OSBORNE A. D.
Published: March 2008

A detailed study, throughout life, of the coliform and Escherichia coli gut flora of two pigs, is presented. One pig was given oral tetracycline for 3 d on two separate occasions; the other pig was not treated and housed separately. The fluctuations in numbers of coliforms, O‐serotypes of E. coli, the occurrence and persistence of antibiotic resistance, and their interrelations, are analysed for both animals. Oral tetracycline profoundly affected the proportion of antibiotic sensitive and resistant E. coli, and, by selecting for R‐factor bearing O‐serotypes, limited the number of O‐serotypes isolated from individual faceal specimens. Specific O‐serotypes exhibited marked differences in their ability to persist in the gut of the control pig. The R‐factor bearing O‐serotypes, selected by tetracycline treatment, also showed differences in ability to persist after treatment indicating that properties other than the possession of R‐factors, decide colonizing ability. The size of the colony sample for serotype analysis is discussed.
A Rapid Colony Test for Thiaminase Activity
Authors: EDWIN E. E. , SHREEVE JEAN E. , JACKMAN R.
Published: March 2008

A rapid method for the detection of very small amounts of thiaminase activity produced by bacterial colonies is described. It can be used routinely in screening for thiaminase‐producing bacteria and other colony‐forming micro‐organisms and offers considerable advantages over other methods.
The Maceration of Vegetable Tissue by a Strain of Bacillus subtilis
Authors: CHESSON A. , CODNER THE LATE R. C.
Published: March 2008

Pectate lyase (PAL EC 4.2.2.2), pectinesterase (PE EC 3.1.1.11), L‐arabinanase, D‐xylanase, D‐galactanase and neutral protease activities were identified in culture filtrates prepared from a strain B3 of Bacillus subtilis isolated from carrot. The PAL was purified by ion‐exchange chromatography and iso‐electric focusing and its properties examined. PAL had a pI of 9·85 and a molecular weight of 33000. Optimum activity occurred at pH 8–9 and 60–65°C. Calcium and to a lesser extent strontium were stimulatory while ethylenediamine tetraacetic acid led to inactivation. Thin layer chromatography separations of the end products of reactions and viscosity measurements suggested that the enzyme acted in a random manner. When examined over a range of pH values both culture filtrate and the purified PAL produced two distinct peaks of maceration (pH 6–6·5 and 8–9) against carrot or potato tissues. Evidence was obtained that although the presence of lyase was the sole external factor responsible for the maceration of carrot at pH 6·0, it acted in conjunction with a heat‐labile, high molecular weight factor extractable from carrot tissue. Carrot extracts were unable to macerate carrot but liberated reducing groups from polygalacturonic acid and it is suggested that the factor may be, in part at least, carrot polygalacturonase. Maceration at pH 8·5 was largely accounted for by PAL and PE activities.
An Improved Electrophoretic Method for Identifying Antibiotics with Special Reference to Animal Tissues and Animal Feeding Stuffs
Authors: SMITHER R. , VAUGHAN D. R.
Published: March 2008

Fifty antibacterial agents, mainly antibiotics, were examined by a high voltage electrophoretic technique which determined their migration distances in agar and agarose gels at both pH 6·0 and 8·0. Comparison of the different migration distances in the two gels formed the basis for identification. Bio‐autography, using Bacillus cereus var. mycoides or Micrococcus luteus, was used to visualize the antibiotics. The method was satisfactory for identifying many antibiotics in animal tissues and animal feeding stuffs, and was capable of distinguishing antibiotic activity from that of naturally occurring inhibitors often present in those materials. It has also been used to identify antibiotics in urine and pharmaceutical preparations, and a wider application in medical microbiology is indicated.
The Effect of Nitrate and Nitrite on the Microbial Flora of Wiltshire Bacon after Maturation and Vacuum‐packed Storage
Authors: SHAW B. G. , HARDING CHARMAIGNE D.
Published: March 2008

Unsmoked Wiltshire bacon was produced with and without nitrate and with different concentrations of nitrite. Micrococci, Moraxella spp. and Moraxella‐like organisms were the most common bacteria on the bacon after maturation when there was little difference between the microflora of the various back bacon. Collar bacon cured without nitrate carried much higher numbers of Moraxella spp. than that cured with nitrate. Micrococci and lactic acid bacteria usually predominated after vacuum‐packed storage. Inclusion of nitrate in the cure increased the numbers of micrococci but did not reduce stability on storage. The highest numbers of lactic acid bacteria were present on bacon containing the lowest initial concentration of nitrite (34 parts/106) and it is thought that nitrite may delay the souring which these bacteria cause in vacuum‐packed bacon.
Studies on the Production of Extracellular Proteinases by a Non‐pigmented Strain of Chromobacterium lividum Isolated from Abattoir Effluent
Authors: DAINTY R. H. , ETHERINGTON D. J. , SHAW B. G. , BARLOW J. , BANKS G. T.
Published: March 2008

A highly proteolytic bacterium isolated from abattoir effluent was identified as a non‐pigmented strain of Chromobacterium lividum. Ferrous or ferric ions at concentrations between 1·8 × 10‐5 and 9 × 10‐4 g ions/1, which is 2–3 orders of magnitude greater than that required for growth, were essential for extracellular proteinase production in aerated but not in static culture. Co2+, Ni2+, Mn2+, Cu2+ or Zn2+ ions could not replace iron. Four proteinases (I‐IV) were produced in static culture, but only proteinase I was formed in significant quantities in aerated culture. With both forms of culture amino nitrogen was essential for proteinase production; glucose inhibited formation in aerated, but not static, cultures. Growth occurred over the range 1–33 °C, whereas proteinase production ceased at 27 °C, with maximum activity at 13 °C. Proteinase production appeared to be controlled by an interaction between iron, oxygen tension and glucose.
Airflows In and Around Linear Downflow ‘Safety’ Cabinets
Authors: CLARK R. P. , MULLAN B. J.
Published: March 2008

Schlieren photography has been used to visualize the airflows in and around three re‐circulating linear downflow cabinets. The results show that there is an air ‘bulge’ at the front opening that allows air from within the cabinet to spill out towards the operator. Hand movements within, and activity just outside, cause air to be expelled from these cabinets. Bunsen burners within the cabinets destroy the linear nature of the downflowing air streams. The results indicate that the operator protection afforded by these cabinets may be much less than is generally recognized.
Sterilization by Means of Hydrochloric Acid Vapour
Authors: MUYS G. TUYNENBURG , VAN RHEE RENÉE , LELIEVELD H. L. M.
Published: March 2008

As heat sterilization of glass bottles often results in breakage and of most plastic containers in deformation, we investigated a rapid low‐temperature sterilization method as an alternative. Vapour evolving from hydrochloric acid was chosen because it does not leave toxic residues which might contaminate food packed in treated containers. Vapour evolving from 0.25 ml of 31% (w/w) hydrochloric acid reduced the number of viable spores of aerobic and anaerobic bacteria in bottles (300 ml) by a factor of at least 2500 and that from 0.01 ml of 37% (w/w) hydrochloric acid reduced the number of mould spores by a factor of over 40 000 within 5 min at 20°C.
Mycotoxin Producing Potential of Fungi Associated with Dry Shrimps
Authors: WU M. T. , SALUNKHE D. K.
Published: March 2008

Among 114 fungi isolated from 20 dry shrimp samples, 27 isolates were capable of producing mycotoxins. Aspergillus and Penicillium were‐the‐predominant fungi. Two of 3 Aspergillus flavus could produce aflatoxin B1 and G1 on yeast extract sucrose medium and on surface sterilized dry shrimps. For other toxigenic species, toxicity was found mostly in the chloroform extracts of cultures. Visibly mouldy dry shrimps had significantly higher moisture content than the non‐mouldy ones. Most of the fungi were isolated from mouldy samples.
The Influence of High Concentrations of Carbon Dioxide on the Germination of Bacterial Spores
Authors: ENFORS S.‐O. , MOLIN G.
Published: March 2008

The influence of carbon dioxide at 1–55 atm on the germination of Clostridium sporogenes, Clostridium perfringens and Bacillus cereus spores in a complex medium was studied. The germination studies at atmospheric pressure were done in the pH range 5.2–6.7. Controls at the same pH were done in 100% nitrogen. Carbon dioxide at atmospheric pressure (1 atm) inhibited the spore germination of B. cereus spores but strongly enhanced the germination rate of those of the clostridia. Spore germination of Cl. sporogenes and Cl. perfringens was inhibited completely at 10 atm and at 25 atm, respectively. The germination rate in carbon dioxide or nitrogen was generally higher at pH 6.7 than at 5.2–6.0.
A Bacteriological Survey of the Domestic Environment
Authors: FINCH J. E. , PRINCE JEAN , HAWKSWORTH MAUREEN
Published: March 2008

The results of a survey of the bacterial flora in many sites in 21 homes are discussed. In all areas both wet and dry, coagulase negative, Gram positive cocci and Bacillus spp. were found. Wet areas such as kitchen sinks and drains contained large numbers of Escherichia coli and sometimes Klebsiella pneumoniae, Citrobacter and Enterobacter spp. In toilet areas, little evidence was found of contamination with organisms of faecal origin. Of 47 samples taken from teacloths and towels 22 were contaminated with Staphylococcus aureus although the actual numbers of this organism were low. Pseudomonas aeruginosa was isolated from several sites in one home only.
A Cultural Method for the Detection of Pullulan—Degrading Enzymes in Bacteria and its Application to the Genus Bacillus
Authors: MORGAN F. J. , ADAMS K. R. , PRIEST F. G.
Published: March 2008

Pullulan in a solid growth medium can be precipitated selectively with ethanol. Clear zones due to pullulan hydrolysis surround microbial colonies which produce the appropriate enzyme. When this procedure was applied to 297 strains representing 26 species of the genus Bacillus, 138 (46%) of the organisms were shown to hydrolyze pullulan.
The Measurement of Electron Transport System Activity in Freshwater Benthic and Planktonic Samples
Authors: JONES J. G. , SIMON B. M.
Published: March 2008

The measurement of electron transport system (ETS) activity in freshwater benthic and planktonic samples was examined. Significant improvements in sensitivity were obtained by increasing the concentration of substrates and of Triton X‐100 in the extraction buffer and by changing the buffer system. The mechanical homogenization procedures which have been used previously to extract the enzymes were shown to be inadequate yielding, at best, 25% of the activity obtained by ultrasonication. The yield of enzymes from sediments was greatly affected by the degree of dilution used and previously published methods would appear to be inadequate. ETS activity correlated well with biological oxygen uptake and, in individual water and sediment profiles, with microbial numbers and biomass. At a more general level, however, the ETS: biomass ratio showed considerable variation.
Kinetics of Inactivation of Aspergillus flavus and Aspergillus terreus Conidiospores by Amphotericin B in the Presence of Serum
Authors: MBAKWEM CHIAKA E. , MATHISON G. E.
Published: March 2008

Survival curves for conidiospores of Aspergillus flavus and A. terreus suspended in tissue culture medium containing 25% horse serum and different concentration of amphotericin B (as Fungizone) were compared. Dormant conidiospores were relatively insensitive. Conidiospores incubated in the absence of the drug became increasingly susceptible and the relationship between the duration of preincubation and numbers of conidia surviving consequent exposure to antibiotic was exponential. Of the two species, A. flavus was much more sensitive to amphotericin than A. terreus and in both species conidiospores harvested from young (4 d) cultures were much more sensitive than older conidia, harvested after storage for between 3 and 13 weeks. Variations in death rates for conidiospores of different ages and physiological states and the shapes of the survival curves are explained in terms of antibiotic penetration, pregermination events and germination inhibition.
A Microbiological Quality Control Procedure Based on Tube Counts
Authors: ASPINALL L J. , KILSBY D. C.
Published: March 2008

A microbiological quality control procedure requiring 9 tubes is described. It is designed so that (1) the probability of rejection exceeds 0·95 when the density of the organisms exceeds a specified critical level, (2) the probability of acceptance exceeds 0·95 when the density of the organisms is less than one‐fifth of this critical level, and (3) estimation of density is adequate over a reasonable range beneath this critical level.
A Note on the Effect of Different Types of Agar on the Recovery of Heated Escherichia coli K‐12
Authors: PELLON JOSE R. , GOMEZ REINALDO F.
Published: March 2008

Escherichia coli K‐12 plated immediately after heat treatment yielded higher plate counts on a minimal medium solidified with Agar Purified (Difco) than on the same medium containing Bacto‐Agar (Difco).

It was concluded that the heat resistance of bacteria can be evaluated only with the use of agar media that are known to be non‐inhibitory to the test organisms after heat treatment.
Random Number Sampling Method for Estimation of Lactic Acid Bacteria
Authors: ORDOÑEZ J. A.
Published: March 2008

A procedure for counting individual organisms or groups with very close cultural characteristics in complex mixtures is described. The method is based upon growth in a medium favourable to all organisms whose enumeration is attempted, selecting 20% of the colonies by the random number sampling method and submitting them to appropriate identification tests.
Contamination of the Deep Tissues of Carcasses by Bacteria Present on the Slaughter Instruments or in the Gut
Authors: MACKEY B. M. , DERRICK CHRISTINE M.
Published: March 2008

Possible routes by which bacteria might reach the deep tissues of carcasses were tested by placing genetically ‘marked’strains of Escherichia coli, Clostridium perfringens or Bacillus thuringiensis on slaughter instruments before use and examining deep tissue samples for their presence post mortem. Bacteria present on the captive bolt pistol were recovered from the spleens of beef cattle and those placed on the pithing rod were found in both spleen and muscle of the flank and neck. Bacteria from the throat cutting (‘stick’) knife were isolated, on different occasions, from the heart, lung, spleen, liver and kidneys of sheep though rarely from their muscles. Orally administered bacteria were found in the spleen and lung, but not the musculature, of pigs.
The Incidence and Serotypes of Clostridium perfringens on Beef, Pork and Lamb Carcasses
Authors: SMART J. L , ROBERTS T. A. , STRINGER M. F. , SHAH N.
Published: March 2008

Examination by swabbing a 100 cm2 area adjacent to the anus demonstrated Clostridium perfringens on 29 of 100 beef, 66 of 100 pork and 85 of 100 lamb carcasses samples before chilling at a commercial abattoir at the end of the slaughter line. Numbers were generally low (20/100 cm2). Serotypes implicated in a high percentage of food poisoning outbreaks in the UK were detected at about the same frequency as others.
Antibacterial Activity of Povidone Iodine towards Non‐sporing Bacteria
Authors: LACEY R. W.
Published: March 2008

The antibacterial activity of povidone iodine was examined in vitro in saline, in nutrient broth, in simulated ulcer experiments and in the presence of blood components. Minimum inhibitory and minimum bactericidal concentrations were within a narrow concentration range. Nutrient broth and plasma had little inactivating activity but 1 g haemoglobin inactivated 50 mg of free iodine: experiments with 125I showed that uptake of iodine by red cells occurred rapidly. Optimal antimicrobial effects in clinical use should be achieved in relatively blood‐free situations. Povidone iodine produced a potent, and sometimes persistent bactericidal effect towards bacteria on healthy skin. It is suggested that antiseptics such as povidone iodine should continue to replace topical antibiotics for prevention and treatment of wound infection.
Isolation and Characterization of Uracil‐Degrading Clostridia from Soil
Authors: MEAD G. C. , ADAMS B. W. , HILTON M. G. , LORD P. G.
Published: March 2008

Five strains of uracil‐degrading clostridia were isolated from soil using an enrichment medium containing uracil as the principal energy source. All the isolates resembled Clostridium glycolicum, although they lacked the characteristic ability to ferment ethylene glycol.

Both representative isolates and a reference strain of Cl. glycolicum degraded uracil and produced β‐alanine when grown in a semi‐defined medium. Thus, the uracil‐degrading activity was similar to that described previously for Cl. uracilicum.
The Use of Standardized Reference Antigens in the Serogrouping of Streptococci
Authors: DENT V. E. , MARSH P. D.
Published: March 2008

Streptococci isolated from the dental plaque of five animal species were identified by physiological and serological methods. Twenty‐nine strains of streptococci considered to resemble Streptococcus mitior or Strep. bovis on the basis of physiological data reacted with Lancefield group B or group K antisera respectively in tube precipitation tests. Further serological studies with standardized antigens from known serogroup B and K streptococci revealed that only three of these 29 isolates had been serogrouped accurately and carried the appropriate group antigen. Comparisons were made between the reactivity of the antisera produced by Difco and Wellcome Reagents with acid and autoclaved extracts of the strains. It was shown that the accuracy of serogrouping such isolates could be improved if the tests were made in a gel diffusion system that included a reference antigen.
Nitrogen Fixation in a Biotype of Erwinia herbicola Resembling Escherichia coli
Authors: NEILSON A. H.
Published: March 2008

Two nitrogen‐fixing members of the Enterobacteriaceae have been isolated from paper mill process water and compost. Although they closely resembled Escherichia coli, detailed biochemical characterization of these and 7 other isolates established that they should be assigned to a biotype of Erwinia herbicola. They may be distinguished from E. coli by their lack of amino acid decarboxylase activity, their ability to utilize cellobiose and malonate and to ferment cellobiose and amygdalin. In one of them, the capacity to fix nitrogen, ferment cellobiose and utilize malonate was resistant to the effects of ethidium bromide, acridine orange and sodium dodecyl sulphate, and the ability to utilize cellobiose could not be transferred on to E. coli or Salmonella typhi. It is therefore concluded that these characters are not carried on transferable plasmids. Forty‐eight strains of E. coli of varying origin were examined for acetylene reducing activity and all were found to be negative. It is concluded that hitherto no naturally occurring strains of E. coli have been shown to fix nitrogen.
Isolation of Yersinia enterocolitica‐resembling Organisms and Alteromonas putrefaciens from Vacuum‐Packed Chilled Beef Cuts
Authors: SEELYE R. J. , YEARBURY B. J.
Published: March 2008

Yersinia enterocolitica‐resembling organisms were found at levels of 107/g on a high pH (pH ≧ 6·0) vacuum‐packaged beef striploin held for 6 weeks at 0·2°C, but did not exceed 105/g on normal pH (pH < 6·0) striploins held for 10 weeks. Gram negative bacteria that produced H2S on peptone iron agar were isolated from high pH vacuum packed striploins. These organisms were identified as Alteromonas putrefaciens. They attained levels of about 107/g in 6 weeks at 0–2°C, at which time greening of the fat surface and ‘drip’had occurred. On meat of normal pH, counts of A. putrefaciens were less than 104/g after 6 weeks and no greening was evident.
A Comparison of the Fluorescent Antibody Method and a Standardized Cultural Method for the Detection of Salmonellas
Authors: GIBBS P. A. , PATTERSON J. T. , EARLY J.
Published: March 2008

The results of routine use of the indirect fluorescent antibody (FA) technique using the Spicer‐Edwards H antisera set are reported for a range of agricultural and food samples. The FA technique was used on samples after the pre‐enrichment incubation period in the proposed ISO method for isolation of salmonellas. The numbers of FA false positive samples (ca. 5% overall) and FA false negative samples (ca. 1·3%) were low, but some originally FA false positive results were later shown to be false negative cultural results.
The Heterotrophic, Nitrate‐Reducing Bacterial Flora of Grasmere, English Lake District
Authors: HORSLEY R. W.
Published: March 2008

During 1976 the temperature, dissolved oxygen and nitrate content of Grasmere water at 6 m and 20 m depth were determined on a seasonal basis and the isolated heterotrophic, nitrate‐reducing bacterial flora analysed both quantitatively and qualitatively under aerobic and anaerobic conditions. Throughout the year 8 population cycles of nitrate‐reducing heterotrophs were observed to occur simultaneously at both horizons which related to changes in the nitrate and dissolved oxygen content of the water. Nitrite producers were most numerous during the isothermal and early thermally stratified periods of the lake water, particularly when the nitrate content was rising. The qualitative analyses indicated seasonal variation in the bacterial populations isolated on the culture media and the dominant taxonomic groups could be related to the nitrate and dissolved oxygen content of the lake water. Pseudomonas. Moraxella/Acinetobacter, Flavobacterium/Cytophaga, Aeromonas and Enterobacteriaceae were the principal taxonomic groups in the Grasmere heterotrophic, nitrate‐reducing flora. Aeromonas with, possibly, Pseudomonas and Enterobacteriaceae are implicated in lowering the nitrate content of Grasmere water at 20 m depth when it becomes anoxic.
Anaerobic Fish Spoilage by Bacteria I. Biochemical Changes in Herring Extracts
Authors: STRØM A. R. , LARSEN H.
Published: March 2008

Water extracts of herring fillets were used as laboratory model substrates for the study of anaerobic bacterial spoilage of fish stored in bulk. The organisms studied (Enterobacter sp., str. NTHC 151, Proteus sp., str. NTHC 153, and Aeromonas sp., str. NTHC 154) were selected for by an enrichment method designed to isolate the bacteria having the highest anaerobic growth yields in these herring extracts. The extracts were then inoculated with pure cultures of the bacteria and incubated anaerobically at 15°C. Chemical analyses of the extracts were carried out at the start and at the end of the incubation period. The compounds determined accounted for 88% of total carbon and 93% of total nitrogen of the sterile extracts. Ribose (free and bound), free hexoses and lactate were the main substrates for the growth of the bacteria. These compounds were converted to acetate and CO2; hydrogen liberated by these processes was used for the quantitative reduction of trimethylamine oxide to trimethylamine. Fermentation balances support the contention that the biochemical changes observed represent the quantitative dominating chemical events in the herring extracts as a result of the development of the spoilage bacteria.
The Production of Antisera to the Klebsiella Capsular Antigens
Authors: EDMONDSON A. S. , COOKE E. MARY
Published: March 2008

Three methods of antiserum production have been compared. One of these consistently gave rise to greater homologous quellung titres and was used routinely. A modification of this method using vaccines consisting of washed, killed suspensions of type strains resulted in no significant increase in titres or decrease in cross‐reactions. Considerable differences were found between the homologous quellung titres and cross‐reactions of antisera prepared in the same laboratory on different occasions.
Heat‐resistant Bacteria in Pasteurized Whole Egg
Authors: PAYNE J. , GOOCH J. E. T. , BARNES ELLA M.
Published: March 2008

Samples of egg melange taken from an egg packing station contained an average of 7·3 x 104 organisms/ml which survived laboratory pasteurization at 65°C for 3 min. Many of the organisms surviving pasteurization were found to be coryneform bacteria related to Microbacterium lacticum which could be differentiated into several groups. The remainder were a miscellaneous collection of unidentified cocci and coccobacilli and some Bacillus spp. The coryneform bacteria were shown to be the most heat‐resistant isolates with negligible loss of viability after 60 min at 65°C, At least two of the representative strains were very heat‐resistant, 0·01% surviving 20 and 38 min at 80°C in phosphate buffer at pH 7·1. Growth tests showed that none of the isolates grew at 5°C after 10 d incubation but those capable of growing most rapidly at 10° and 15°C were also the most heat‐resistant. Such strains had a doubling time at 15°C of between 6 and 8 h in whole egg. Freezing the coryneform bacteria in liquid whole egg at –18°C had negligible effect on viability or heat‐resistance at 65°C.
An Unsterilized Soil‐agar Technique for Studying Rhizobium‐plant Relationships
Authors: DOUKA CATHERINE E.
Published: March 2008

The value of unsterilized soil‐agar slopes for studying the effect of chemical and biological characteristics of soil on the rhizobia‐plant relationships has been demonstrated by examining the characteristics of 4 strains of Rhizobium meliloti isolated from salt‐affected soils of Greece. The technique enabled information to be obtained on: the survival of indigenous rhizobia and bacteria; the survival of rhizobia added to soil; the antagonistic‐symbiotic effects, and the effectiveness of inoculation on nitrogen fixation to be closely followed.
Changes in Heat Resistance During Storage of Bacillus stearothermophilus Spores from Complex and Chemically defined Media
Authors: ALPIN S. J. , HODGES N. A.
Published: March 2008

Spores of Bacillus stearothermophilus produced on a glucose depleted defined medium and on a complex medium exhibited a loss of viability and a marked reduction in heat resistance as a result of freezing (–18°C) and freeze drying. Little further change in heat resistance occurred during subsequent storage under these conditions.

Spores from the defined medium exhibited an increase in heat resistance during sto1rage as aqueous suspensions for three months at 22°C and 4°C; the resistance of spores from a complex medium was unchanged.
An Electrophoretic Study of Peptidases in Starter Streptococci and in Cheddar Cheese
Authors: CLIFFE A. J. , LAW B. A.
Published: March 2008

A modified electrophoretic starch gel technique was developed and applied to the detection of peptidase activity in zymograms of crude extracts of Group N streptococci and extracts of cheese made with these organisms. The method required only 0–36 mg of peptide substrate for each test. Dipeptidase, tripeptidase and aminopeptidase activities were detected in strains of Streptococcus cremoris and Strep, lactis and in curds and cheeses made with these organisms.

Intracellular and extracellular fractions of Strep, lactis showed similar peptidase activity but with Strep, cremoris there were fewer peptidases in extracellular fractions. The peptidase composition of curd and cheese extracts of different ages was dependent upon the strain and species of starter streptococcus used in making the cheese.
Fatty Acid and Polar Lipid Composition in the Classification of Cellulomonas, Oerskovia and Related Taxa
Authors: MINNIKIN D. E. , COLLINS M. D. , GOODFELLOW M.
Published: March 2008

Strains representing the taxa Cellulomonas, Oerskovia, Brevibacterium fermentans, Corynebacterium manihot and Nocardia cellulans were degraded by acid methanolysis and the non‐hydroxylated fatty acid esters released examined by thin‐layer and gas chromatography. The major fatty acid in all strains was 12‐methyltetradecanoic acid (anteiso C15) which occurred together with other anteiso acids, iso and straight‐chain acids. The fatty acid profiles of the cellulomonads were distinguished by the presence of 13‐carbon acids and significantly higher proportions of straight‐chain acids than found in the other test strains whose profiles were closely similar to one another. Two‐dimensional thin‐layer chromatography showed that almost identical and very characteristic polar lipid patterns were given by all the organisms under study: the only major components were diphosphatidylglycerol, phosphatidylinositol and two phospho‐glycolipids chromatographing similarly to, but distinguishable from, the mono‐ and diacyl phosphatidylinositol dimannosides characteristic of Nocardia and other actinomycetes. The accumulated lipid data support the reclassification of B. fermentans, Cor. manihot and N. cellulans in the genus Oerskovia.
Effect of Handling Procedures on the Post‐process Contamination of Retort Pouches
Authors: MICHELS M. J. M. , SCHRAM B. L.
Published: March 2008

The effect of handling flexible retort pouches has been studied in relation to their integrity and resistance to post‐process contamination (‘leaker spoilage’). Tests were made using a pilot‐plant processing line on which pouches were filled with broth, sealed, heat‐processed and subjected to three post‐process handling treatments. Using Enterobacter aerogenes as an indicator organism, it was shown initially that rough instead of careful handling during loading of the retort increased the proportion of punctured pouches from 0.06 to 0.27%. The effect of post‐process handling procedures on leaker spoilage was studied using pouches deliberately punctured with a needle of 100 μm diameter. When these pouches were cooled in tap water, unloaded manually from the retort and stored wet, the incidence of post‐process contamination was 90%. With similar pouches which were dried immediately after manual unloading and stored dry, the contamination rate was only 10%, whereas cooling in chlorinated water and drying before manual unloading reduced the contamination rate of punctured pouches to less than 1%. It was concluded that manual handling of dry pouches presents an acceptable alternative to complete mechanical handling of freshly heat‐processed pouches, which was proposed in a Code of Practice for retort pouches formulated in 1971.
Effect of Iron on Conversion of Acetic Acid to Methane During Methanogenic Fermentations
Authors: HOBAN D. J. , VAN DEN BERG L.
Published: March 2008

Addition of iron (as a solution of reagent grade FeCl2, up to 20 mmol/1) to a methanogenic culture utilizing acetic acid markedly increased conversion of acetic acid to methane. The optimum soluble iron concentration was between 0.2 and 2 mM, with higher concentrations becoming slightly less stimulating. Most of the iron added precipitated within days after addition (mostly as ferrous carbonate or phosphate). Conversion of acetic acid to methane in liquid from municipal sewage digesters and from laboratory food processing waste digesters was also increased markedly by addition of iron. Results indicate that optimization of the conversion of acetic acid to methane in methanogenic fermentations requires soluble iron levels many times higher than those often required for maximum growth and activity in microbial cultures.
A Rapid Bioassay Method for Gramicidin by Measuring Rubidium Ion Leakage from Streptococcus faecalis
Authors: MILLER S.J. P.
Published: March 2008

Gramicidin was seen to promote rapid release of Rb+ from cells of Streptococcus faecalis ATCC 10541 which had been previously enriched with this cation. This response was logarithmic between gramicidin concentrations of 0.25 μg/ml and 2.5 μg/ml. This efflux was measured by flame emission spectroscopy. The results presented here form the basis for a potential rapid bioassay for gramicidin.
Chromogenic Assay Method of Lipopolysaccharide (LPS) for Evaluating Bacterial Standing Crop in Seawater
Authors: MAEDA M. , TAGA N.
Published: March 2008

A chromogenic method, based on amoebocyte lysate of horseshoe crab and amino acids‐para‐nitroanilide substrate was employed to quantify lipopolysaccharide (LPS) as a measure of the bacterial standing crop in seawater. The range over which LPS could be reliably determined by this method was from 0.2 to 10 ng/ml of sample, and the method reported here could have several advantages compared with the turbidity determination method.

Vertical distributions of total and particulate LPS were parallel in seawater column. Particulate LPS was not shown to be related to the biomass of total bacteria in some cases, but correlated with the numbers of large bacterial cells whose size was greater than 1 fan in length.

In most of the profiles investigated in the shallow sea there was no parallel relationship between LPS and chlorophyll‐a whereas in some cases the profiles were similar.

In growing cultures of Vibrio anguillarum the content of cellular LPS as a percentage of the total cellular carbon during the 3 d growth ranged from 6–15% (w/w).
Growth of Cutaneous Propionibacteria on Synthetic Medium; Growth Yields and Exoenzyme Production
Authors: HOLLAND K. T. , GREENMAN J. , CUNLIFFE W. J.
Published: March 2008

A synthetic medium containing only low molecular weight components has been developed to grow Propionibacterium acnes (P. acnes), P. avidum and P. granulosum.

The medium supported the growth of 30/32 typed strains, and when solidified with agar supported the growth of these bacteria isolated directly from the skin. The mean overall efficiency of isolation on the synthetic medium was 57% that of reinforced clostridial medium (RCM).

Batch culture experiments with glucose, fructose, glycerol or arginine in the medium showed that the concentrations as well as the type of carbon energy sources used could effect growth and exocellular enzyme production by these organisms.
Whole‐serum Assay of L‐methionine using a Chloramphenicol Resistant Strain of Pediococcus acidilactici
Authors: TENNANT G. B.
Published: March 2008

A chloramphenicol resistant strain of Pediococcus acidilactici (NCIB 11432) was used in a work‐simplified, whole‐serum assay of L‐methionine. The assay compared favourably with an extraction technique and was much simpler to perform.
Identification of Pseudomonas tolaasi: the White Line in Agar and Mushroom Tissue Block Rapid Pitting Tests
Authors: WONG W. C. , PREECE T. F.
Published: March 2008

A sharply defined white line of precipitate forms in Pseudomonas Agar F (Difco) between the opaque white colonies of Pseudomonas tolaasi and translucent colonies of certain unidentified pseudomonads. This visible interaction has been utilized in a specific and reliable method for the identification of Ps. tolaasi. The white line test was positive when 113 isolates of Ps. tolaasi from five different countries were examined, whereas 154 isolates of pseudomonads other than Ps. tolaasi, including Ps. corrugata, Ps. delphinii, Ps. fluorescens, Ps. lachrymans, Ps. marginalis, Ps. pastinaceae, Ps. phaseolicola, Ps. aeruginosa, Ps. putida, Ps. syringae, Ps. mors‐prunorum, Ps. cichorii, Ps. antirrhini, Ps. viridiflava, Ps. caryophylli, Ps. cepacia, Ps. mendocina, Ps. stutzeri, Ps. acidivorus and Ps. lemoignei did not give the white line reaction with a reacting translucent colony pseudomonad. Browning of mushrooms in host tests does not help in the identification of Ps. tolaasi, but a conspicuous pitting produced in less than 10 min at the cut surface of mushroom tissue is as specific as the white line test in detecting Ps. tolaasi in suspension in distilled water.
Development of a Selective Medium for the Isolation of Clostridium sporogenes and Related Organisms
Authors: FRYER T. F. , MEAD G. C.
Published: March 2008

An attempt was made to develop a selective isolation medium for Clostridium sporogenes and related organisms based on the ability of these organisms to obtain their energy for growth by means of coupled oxidation‐reduction reactions between appropriate pairs of amino acids (Stickland reaction). Using a semi‐defined basal medium containing various combinations of amino acids, it was found that Cl. sporogenes utilized a wider range of amino acid pairs than strains of five other species of clostridia known to carry out a Stickland‐type fermentation.

With alanine and proline as the principal energy sources and the medium solidified with agar. it was shown that reference strains of Cl. sporogenes and proteolytic Cl. botulinum types A, B and F could be recovered almost quantitatively, with or without prior heating at 80 °C for 10 min. By contrast, growth of test strains of Streptococcus faecalis, Strep. faecium, ‘saccharolytic’Cl. botulinum types B, C, D, E and F and ‘proteolytic’ strains of types C and D was suppressed on this medium, as were strains of 26 other species of clostridia.

Addition of 50 μg/ml of polymyxin to the agar medium had no detectable effect on the recovery of Cl. sporogenes or Cl. botulinum. When samples of soil and mud were plated on the antibiotic‐containing medium, 63.1% of 225 isolates thus obtained were identified as Cl. sporogenes/botulinum.
Flow Microcalorimetric Studies of Yeast Growth: Fundamental Aspects
Authors: PERRY B. F. , BEEZER A. E. , MILES R. J.
Published: March 2008

The importance of factors such as cultural conditions e.g. organism background, inoculum density and glucose concentration are explored and their effects on the experimental recording discussed. The relevance of these findings to microbial microcalorimetry in general and to microcalorimetric identification of organisms in particular is described. The conclusions drawn are (i) that microbial identification by microcalorimetry is not possible and (ii) that great caution must be exercised in interpreting metabolic data derived from microcalorimetric studies.
Policies in the U.K. to Ensure that a Food Factory does not Distribute Food‐Poisoning Micro‐Organisms—A Personal View*
Authors: HOWIE SIR JAMES
Published: March 2008

THERE ARE NO POLICIES which will certainly ensure that food factories do not distribute food‐poisoning micro‐organisms. Indeed, those responsible for the management of food factories deserve and require sympathetic understanding of their problems; for most of these are at present not of their own making, never wholly soluble, and ever liable to close down production and blemish their reputation.
A Note on Screening Hydrogen Peroxide‐producing Lactic Acid Bacteria Using a Non‐toxic Chromogen
Authors: MARSHALL VALERIE M.
Published: March 2008

An agar plate method for detection of hydrogen peroxide‐producing bacteria using a non‐carcinogenic chromogen is described.
Antibiotic and Heavy Metal Resistance of Pseudomonas aeruginosa Isolated from Soils
Authors: MARQUES ANA M. , CONGREGADO F. , SIMONPUJOL DOLORES M.
Published: March 2008

1. 71 strains of Pseudomonas aeruginosa were isolated from soils and tested for resistance to antibiotics and heavy metals.

2. 6% were resistant both to 12/14 drugs and 9/12 heavy metals tested.
The Antibacterial Properties of Sodium Dichloroisocyanurate and Sodium Hypochlorite Formulations
Authors: BLOOMFIELD SALLY F. , MILES GWYNEDD A.
Published: March 2008

Disinfection capacity determinations using solutions prepared from effervescent tablets of sodium dichloroisocyanurate (NaDCC) and from solutions of sodium hypochlorite (NaOCI) indicated high activity against a range of organisms, which represent adequate safety margins for disinfection. NaDCC showed significantly higher activity than NaOCl solution against all bacterial species tested but activity against Candida albicans was similar. Results indicate that differences in activity between NaDCC and NaOC1 formulations are not entirely due to pH effects and that fundamental differences exist between properties and mode of action of the 2 hypochlorite systems.
Loss of Viability and Metabolic Injury of Staphylococcus aureus Resulting from Storage at 1°, 3°, 5° and 7°C
Authors: PATTERSON THE LATE T. E. , JACKSON H.
Published: March 2008

Staphylococcus aureus incubated in Tryptic Soy Broth at 1°, 3°, 5° and 7°C became increasingly sensitive to Mannitol Salt Agar. Injury, as measured by salt sensitivity, decreased with increasing temperature from 1° to 7°C.
Fimbriae and Haemagglutinins in Erwinias of the Carotovora Group
Authors: CHRISTOFI N. , WILSON MARGARET I. , OLD D. C.
Published: March 2008

1. Thirteen Erwinia carotovora strains produced mannose‐sensitive haemagglutinins associated with the presence of type‐1 fimbriae.

2. Three fimbriate Er. rhapontici strains produced haemagglutinins of the mannose‐resistant and eluting (MRE) type.

3. There were 12 Er. carotovora, 12 Er. atroseptica and 2 Er. chrysanthemi strains that produced no detectable haemagglutinins and were non‐fimbriate.
The Fungal and Bacterial Flora of Stored White Cabbage
Authors: GEESON J. D.
Published: March 2008

1. The predominant organisms isolated from the outer wrapper leaves of freshly harvested white cabbages were: bacteria, yeasts, Alternaria spp., Aureobasidium pullulans, Botrytis cinerea, Cladosporium spp. and Penicillium spp.

2. Few qualitative or quantitative changes were seen in the leaf surface flora during storage at 2°C for up to 33 weeks.

3. Numbers of bacteria, particularly fluorescent and pectolytic pseudomonads, were considerably higher on cabbages drenched with fungicide or water than on corresponding undrenched cabbages.
Scanning Electron Microscopy of Microorganisms on Chicken Skin
Authors: McMEEKIN T. A. , THOMAS C. J. , McCALL D.
Published: March 2008

1. Scanning electron microscopy was used to examine microorganisms in situ on chicken skin. They developed in a layer of material on the surface of the skin. The observations explain the relative ineffectiveness of carcass cleaning procedures and the increased recovery of microorganisms by destructive compared with non‐destructive sampling techniques.
Growth of an Ethane‐utilizing Mixed Culture in a Chemostat
Authors: LINTON J. D. , GODLEY A. R. , BAILEY M. L. , BARNES L. J.
Published: March 2008

Bacteria capable of utilizing ethane as their sole source of carbon and energy at 42° were readily isolated from soil samples obtained from Brunei with batch culture enrichment techniques. No ethane utilizers capable of growth at 42° were isolated, however, from soil samples obtained from Britain. An ethane‐utilizing mixed culture was grown under ammonia limitation in chemostat culture. The lipid content of the culture was inversely proportional to the dilution rate. Similarly, the amount of organic carbon excreted into the culture supernatant was inversely proportional to the growth rate and could be accounted for mainly as carbohydrate. The specific rates of ethane and oxygen consumption, carbon dioxide production and yield from ethane were directly proportional to the dilution rate.
Aerobic Metabolism of Brochothrix thermosphacta Growing on Meat Surfaces and in Laboratory Media
Authors: DAINTY R. H. , HIBBARD CHRISTINE M.
Published: March 2008

Acetoin and acetic, isobutyric and isovaleric acids are major end‐products, and important components of the spoilage odours, of Brochothrix thermosphacta growing aerobically on meat surfaces or in tryptone‐based medium containing glucose, ribose or glycerol. Acetoin and acetic acid are probably derived entirely from the carbohydrates and isobutyric and isovaleric acids from valine and leucine respectively. Glucose and pH are both important factors in controlling the relative amounts of end‐products, low glucose and near neutral pH favouring fatty acid formation, high glucose and lower pH values favouring acetoin formation.
Growth of Bacillus cereus in Media Containing Plant Seed Materials and Ingredients Used in Chinese Cookery
Authors: BEUCHAT L R. , MA‐LIN C. F. ANN , CARPENTER J. A.
Published: March 2008

Growth and sporulation of enterotoxigenic strains of Bacillus cereus in media containing 20 different plant seed flours and meals, with and without added infusions of beef, pork, chicken and shrimp, monosodium glutamate (MSG), and soy sauce, were studied. Suspensions (2%; pH 7–1) of seed flours and meals from diverse botanical origins were found to be excellent sources of nutrients for growth. No correlations could be made between composition of seed materials and rate of cell division. Mean generation times of B. cereus cultured in soy, peanut and rice flour media supplemented with animal flesh infusions were significantly faster (P≤ 0.05) than those of respective controls. Monosodium glutamate (1–2%) and soy sauce (5–10%) stimulated the rate of growth of B. cereus in rice flour medium. Test flours supporting slower growth rates appeared generally to support higher rates of sporulation.
Survival of Salmonella dublin in Pig Slurry During Aerobic Thermophilic Treatment in Batch, Cyclic and Continuous Systems
Authors: GINNIVAN M.J. , WOODS J. L. , O'CALLAGHAN J.R.
Published: March 2008

The survival of Salmonella dublin was investigated in aerobically fermenting and autoclaved pig slurry at a temperature of 55°C. The difference in the decay rates for these two situations was not statistically significant. Initial bacterial concentrations of about 106/ml were reduced to undetectable levels in less than 4 h in both cases, the decimal decay rate based on both sets of data was 1.81/h. Theoretical analysis, based on the decay rate derived from these results, indicated that cyclic feeding and discharging had advantages over the continuous system particularly as retention time increased.
Observations on the Value of a Swab Technique for Determining the Bacteriological State of Milking Equipment Surfaces
Authors: RICHARD J.
Published: March 2008

The reproducibility and efficacy of a swab technique for milking equipment in normal use was studied. Reproducibility was satisfactory when swabbing was done by trained personnel. It was confirmed that swabs pick up only a proportion of the microorganisms present on a surface; this proportion varies with the consistency of the contaminating material, but not with the type of surface on which it occurs. It is concluded that swabs allow the estimation of the maximum ability of a surface to contaminate the milk.

Rigid smooth surfaces of the milking machine are recontaminated by microorganisms originating from joints and complex parts of the machine during rinsing after cleaning. A procedure to evaluate the efficacy of cleaning these surfaces is proposed.
Variability in Microbiological Data from a Stratified Eutrophic Lake
Authors: JONES J. G. , SIMON B. M.
Published: March 2008

A survey of a stratified eutrophic lake was undertaken to determine the degree of variability in direct counts of bacteria, electron transport system activity, ATP concentration, chlorophyll a concentration and chemiluminescence, in the water column and the sediment. Heterogeneity in the horizontal and vertical dimension was studied in detail and the scale of variability was compared with within‐sample and between‐sample errors, and with seasonal fluctuations. Variability was greater in the sediment samples, and the coefficient of variation of samples taken at a single site was often as large as that between sites in a transect across the lake. Although this was not an exhaustive survey, the values provided should allow rough estimates to be made of the number of samples required to achieve a given level of precision in future investigations.