bluuebunny/crossref_metadata_2025 huggingface dataset:
Further Studies on the Suitability of Various Media Containing Antibacterial Antibiotics for the Enumeration of Moulds in Food and Food Environments
Authors: MOSSEL D. A. A. , VEGA CLARA L. , PUT HENRIETTE M. C.
Published: March 2008

Oxytetracycline–glucose–yeast extract agar (OGYA), gentamicin–glucose–yeast extract agar (GGYA) with the antibiotic added separately or sterilized with the medium, chlortetracycline–Rose Bengal agar (CRA), chloramphenicol‐streptomycin agar (PYA) and to a lesser extent, oxytetracycline–gentamicin–glucose–yeast extract agar (OGGYA) with or without Rose Bengal added, have been compared for the selective enumeration of moulds in foods. The results obtained from dried cereal products show that the media are almost equally productive and selective when applied to such foods, but Rose Bengal limits the size of mould colonies. When examining fresh proteinaceous foods, such as minced meat and chicken, CR agars and to a certain extent gentamicin‐containing agars show the distinct advantage of being much more inhibitory towards the psychrotrophic Gram negative rods that predominate in the associated flora of such foods. Oxytetracycline–glucose–yeast extract agar lost its bacteriostatic properties when heavily challenged with proteinaceous substrates and/or incubated for longer periods at 37° or even at 25°. For such applications chloramphenicol was found to be the antibiotic of choice.
The Egg Yolk and Lipolytic Reactions of Coagulase Positive Staphylococci
Authors: OWENS J. J. , JOHN P. C. L.
Published: March 2008

The composition of egg yolk media is important for the identification of egg yolk positive strains of coagulase positive staphylococci. Media with glucose allowed the detection of more egg yolk positive strains than those without it. However, the presence of 50% CO2 in the incubation atmosphere allowed a greater number of egg yolk positive strains to be detected regardless of whether glucose was present or not. This was due to the suppression of lipase activity by CO2 thus allowing total lipid separation indicative of the egg yolk phenomenon. Staphylococcus aureus strains from human nares were egg yolk positive and strongly lipolytic while strains of animal origin and epidermal necrolysis were egg yolk negative and weakly lipolytic.
Some Observations on the Occurrence of the Iron Bacterium Leptothrix ochracea in Fresh Water, including Reference to Large Experimental Enclosures
Authors: JONES J. G.
Published: March 2008

A study of iron bacteria in the hypolimnion of Blelham Tarn and 2 large experimental tubes therein showed that counts of Leptothrix ochracea filaments were proportional to total iron concentration. A regression equation was derived which described the relationship and from which 95% prediction limits of the counts could be obtained. This equation, however, failed to account for a significant proportion of the variability of the bacterial counts, nor could this be explained by changes in the other variables measured. Possible sources of variation are noted, as are results from a vertical profile from another productive lake and the reasons for the occurrence of significantly larger numbers of Leptothrix filaments in one of the enclosures. Changes in the appearance of the sheath of L. ochracea and the capsules of other iron bacteria with a similar distribution pattern, occurred when O2 was absent from some samples.
A Rapid and Direct Plate Method for Enumerating Escherichia coli biotype I in Food
Authors: ANDERSON JUDITH M. , BAIRD‐PARKER A. C.
Published: March 2008

Direct enumeration of Escherichia coli biotype 1 in foods within 24 h has been achieved by a development of the method of Delaney, McCarthy & Grasso (1962) which is based on the production of indole at 44°. Indole positive E. coli growing at this temperature on a cellulose acetate membrane overlaying tryptone bile agar can be demonstrated. Characterization of 555 indole positive colonies from 843 samples of food showed that 95% were E. coli biotype 1 and a further 3·4% were ‘faecal coliforms’. Anaerogenic and non‐lactose fermenting E. coli are detected and the significance of these strains is discussed.
Pediococcus acidilactici NCIB 6990, a New Test Organism for Microbiological Assaying of Pantothenic Acid
Authors: SOLBERG O. , HEGNA IDA K. , CLAUSEN O. G.
Published: March 2008

Pediococcus acidilactici NCIB* 6990 is highly suitable for microbiological assay of pantothenic acid using an agar diffusion method. This bacterium exhibits a high degree of accuracy at much lower pantothenic acid concentrations than Lactobacillus plantarum,† which is commonly used for assaying this vitamin.
Use of a Coulter Counter to Detect Discrete Changes in Cell Numbers and Volume During Growth of Escherichia coli
Authors: SMITHER R.
Published: March 2008

Escherichia coli could be detected at a concentration of 105 cells/ml. Growth curves of the organism grown in filtered tryptone soya broth were made by taking viable and Coulter counts. Both curves were similar in shape and varied little during 10 h growth. Cell volume and volume distribution were seen to vary considerably however, volume reaching a stable minimum value of 0·61 μm3 after 8 h. The Coulter Counter was considered to be potentially useful for detecting significant bacteriuria.
Decarboxylation of Substituted Cinnamic Acids by Enterobacteria: the Influence on Beer Flavour
Authors: LINDSAY R. F. , PRIEST F. G.
Published: March 2008

Many species within the Enterobacteriaceae decarboxylate the substituted cinnamic acids p‐coumaric acid and ferulic acid. The enzyme responsible is principally associated with the ‘free‐living’ genera, Klebsiella, Enterobacter and Hafnia and is absent from Proteus mirabilis, Escherichia coli, Serratia and Salmonella spp. Some strains of Hafnia protea, a common bacterial contaminant of brewers’ yeast display decarboxylase activity towards hydroxycin‐namic acids. These H. protea strains (members of taxonomic group 1) produce higher concentrations of steam‐volatile phenolic compounds when grown in wort than strains lacking the decarboxylase. The addition of ferulic acid or p‐coumaric acid to wort prior to the growth of H. protea group 1 strains increases the concentration of steam‐volatile phenolic compounds thus implicating this route as a source of phenolic off‐flavours in beer.
Inability of Genetic Systems of Bacillus subtilis to Detect a Mutagenic Effect of Low Frequency Ultrasound
Authors: COMBES R. D.
Published: March 2008

Possible mutagenic effects of low frequency (20 kHz) ultrasound have been assessed with genetic systems of Bacillus subtilis. Ultrasound was unable to cause a detectable increase in the spontaneous frequency of back‐mutation irrespective of the degree of killing. Similar treatments were incapable of producing mutagenic lesions that could be detected by the system of transformation after in vitro treatment of DNA. Transforming activity and molecular weight could be reduced without a corresponding decline in linkage between two contiguous markers. It is concluded that mutagenic effects of ultrasound could not be detected using these genetic systems.
Changes in the Microbiology of Vacuum‐packaged Beef
Authors: SUTHERLAND JANE P. , PATTERSON J. T. , MURRAY J. G.
Published: March 2008

The development of the microbial flora on meat stored in vacuum‐bags at 0–2° for up to 9 weeks was studied. Although the proportion of lactic acid bacteria increased relative to the aerobic spoilage organisms, the numbers of the latter continued to increase throughout storage. The initial contamination of the meat before vacuum‐packaging was important; meat with a very low initial number had lower numbers of bacteria throughout storage for up to 9 weeks and steaks cut from such meat which had been stored always had 1–2 days’ additional aerobic shelf life at 4°. Spoilage of these steaks was due either to slime formation and off‐odour associated with high counts of presumptive Pseudomonas spp., or by discoloration and souring (lactic acid bacteria). Extract release volume and pH measurements performed on the vacuum‐packaged primal joints were only of value in determining the onset of aerobic spoilage when large numbers of Gram negative organisms were present, whereas the titrimetric method of spoilage evaluation of the vacuum‐packaged meat showed a correlation with spoilage due to lactic organisms.
Fungi and Clostridia in Hospital Air: the Effect of Air‐conditioning
Authors: LIDWELL O. M. , NOBLE W. C.
Published: March 2008

Settle plates, exposed in a newly‐built, air‐conditioned hospital, were compared with similar samples from a modern, naturally ventilated hospital. Fewer fungal colonies were found in the air‐conditioned hospital. Most airborne fungi found in the naturally ventilated hospital wards are probably introduced with the ventilating air. There was much less difference between the two hospitals in the numbers of Cl. welchii recovered and it seems likely that these organisms are dispersed from human sources within the hospital in numbers comparable to those brought in with the ventilating air in naturally ventilated hospitals. A description of a portable anaerobic incubator suitable for field studies is also given.
A Proteus inconstans which Produces ‘Cabbage Odour’ in the Spoilage of Vacuum‐packed Sliced Bacon
Authors: GARDNER G. A. , PATTERSON R. L. S.
Published: March 2008

The isolation and identification of a species of Proteus inconstans capable of producing ‘cabbage odour’ spoilage of sliced vacuum‐packed bacon are described. Gas chromatographic‐mass spectrometric analysis indicated that the odoriferous compound was methane thiol. Data are presented on the effect of the pH and salt level on the growth of the organism in laboratory media and the production of methane thiol in bacon.
Microbial Spoilage of Fresh Refrigerated Beef Liver
Authors: SHELEF L. A.
Published: March 2008

The types and numbers of micro‐organisms involved in the spoilage of refrigerated beef liver were studied together with pH, hydration and organoleptic changes of the material. Fresh liver harboured a mixed population (c. 1 × 105 organisms/g) of Gram positive cocci, chromogens and non‐chromogens, sporeformers, presumptive coliforms and Gram negative rods. When samples were rejected organoleptically, after 7–10 days at 5°, the contamination attained levels of c. 7–8 × 107 organisms/g. Spoilage was due to souring; the pH fell from 6·3 (fresh liver) to c. 5·9. Lactic acid bacteria were predominant and Gram negative bacteria did not exceed 1·0 × 106 organisms/g. This type of spoilage is explained by the carbohydrate content of c. 5% in liver. The value of pH appears to be a reliable indicator of liver freshness, with a pH of 6·1 indicating incipient spoilage.
Bacteriological Examination of Seawater: Observations on Factors Affecting the Performance of Media
Authors: PAPADAKIS J. A.
Published: March 2008

The performance of MacConkey broth and minerals modified glutamate lactose medium was examined in a series of experiments. It was found that the addition of seawater with or without antibacterial activity and the addition of 3·2% NaCl solution to double strength media all had similar harmful effects on their performance. Also a concentration of 3·2% NaCl in ordinary lactose broth caused a great decrease (P=0·02) in the number of tubes containing coliform organisms. It is concluded that the high salt content of seawater interferes with lactose fermentation by coliforms. This interference was found to be so great that the number of tubes in which coliform organisms and Escherichia coli were detected, dropped from 2·5 to 3·5 times when an equal volume of seawater was added to double strength MacConkey and glutamate media. The results of the last experiment suggest that for best performance of the media, the volume ratio of seawater to medium should be equal or less than 1/10. Also glutamate medium was superior to MacConkey broth (P<0·001), especially in the detection of E. coli.
Development and Properties of Streptomycin Resistant Cultures of Erwinia amylovora Derived from English Isolates
Authors: BENNETT R. A. , BILLING EVE
Published: March 2008

Resistance to 1000 p/m, streptomycin was developed in 3 out of 16 virulent strains of Erwinia amylovora by continuous subculturing on increasing concentrations of the drug. Resistance to various antibiotics, including streptomycin, was more readily developed in strains of Erwinia herbicola. Streptomycin resistance carried on an R factor was transferred by conjugation from Escherichia coli to E. amylovora and to E. herbicola. Resistance to streptomycin was associated with attenuation or, in one case, complete loss of virulence. Doubling times of resistant cultures were greater than those of the parent culture both in shaken broth culture and (with the two attenuated cultures) in apple seedlings. The avirulent culture appeared to persist longer in vivo in the presence of the virulent culture than alone.
Recovery of Escherichia coli and Coliforms from Macerated Shellfish
Authors: AYRES P. A.
Published: March 2008

A comparison of manual and mechanical maceration techniques for the bacteriological examination of molluscan shellfish suggests that mechanical maceration leads to an improved recovery of Escherichia coli. Extensive use of such a technique in the routine examination of shellfish has introduced a standard considerably more rigorous than that proposed originally.
Simple Media Containing Stabilized Tributyrin for Demonstrating Lipolytic Bacteria in Foods and Soils
Authors: MOUREY A. , KILBERTUS G.
Published: March 2008

A medium containing tributyrin stabilized with polyvinyl alcohol was used to demonstrate the lipase activity of bacteria in foods. A modification of this new medium enables a search to be made for lipolytic bacteria in soil.
A Preliminary Investigation into the Role of Yeasts in the Ensiling Process
Authors: WOOLFORD M. K.
Published: March 2008

The activities of six unidentified yeasts isolated from silage were monitored in a defined environment prepared to simulate a grass silage. Lactic acid and acetic acid contents of the silages were higher when yeasts were included in the inoculum used and the yeasts appeared to be beneficial to preservation. The yeasts also contributed to the small quantities of ethanol which were detected. Where a yeast was used as the sole inoculum the pH of the silage remained high, but lactic acid and acetic acid as well as ethanol were present in the resulting silages.
Protein and other Compositional Analyses of Saccharomyces fragilis grown on Coconut Water Waste
Authors: SMITH M. E. , BULL A. T.
Published: March 2008

Saccharomyces fragilis organisms, grown in batch cultures on coconut water and in continuous‐flow cultures on either a defined medium (containing mixtures of glucose, fructose, sucrose and sorbitol) or coconut water, were analysed for macromolecular components, cell wall material and amino acids. The data were used to evaluate the suitability of the yeast as a source of single cell protein. Excess nitrogen was necessary to attain maximum cellular protein contents although the yeast yield was maximized at lower concentrations. Major macromolecular components were present in quantities similar to other food yeasts; the amino acid profile was satisfactory from a nutritional viewpoint and contained high levels of lysine. The product was slightly deficient in cystine and methionine. Some advantages of developing carbohydrate‐based SCP processes, such as that proposed with coconut water, and as alternatives to hydrocarbon‐based processes, are suggested.
Evaluation of a New Design of Bottle Closure for Non‐Injectable Water
Authors: HAMBLETON R. , ALLWOOD M. C.
Published: March 2008

A new design of closure for Non‐Injectable Water bottles has been evaluated. The closure employs a flexible rubber skirt inside the bottle neck to seal the bottle under pressure during autoclaving. Tests employing Bacillus stearothermophilus spore papers and temperature measurements indicated that the annular recess above the cap skirt could be sterilized by a normal autoclave cycle. Pressure measurements showed that the closure maintained a hermetic seal during autoclaving. A comparison between this closure and the DHSS system employing an aluminium screw cap with a flat rubber liner indicated that the new design could prevent the ingress of spray cooling water and offered greater protection of the pouring surfaces of the bottle neck.
Investigations on a Metabolite from Lactobacillus bulgaricus which Neutralizes the Effect of Enterotoxin from Escherichia coli Pathogenic for Pigs
Authors: MITCHELL I. DE G. , KENWORTHY R.
Published: March 2008

Eleven species of lactic acid bacteria when grown on a milk‐based medium reduced the pH value to < 4.7. The cells of nine of these species inhibited the growth of Escherichia coli on agar in Petri dishes. However, only Streptococcus faecium and Lactobacillus bulgaricus gave significant cell free anti‐E. coli activity. Activity against E. coli enterotoxin was also found only in two species. L. bulgaricus and S. faecalis. Part of the activity in the former species was cell free. Further investigation of the cell‐free anti‐enterotoxic activity from L. bulgaricus showed that it had a low molecular weight probably < 103, was not very stable and was independent of the anti‐E. coli activity. Broths containing L. bulgaricus fermented to produce high levels of antienterotoxin were beneficial when added to diets for early weaned pigs. It was inferred that this effect was likely to be caused by the anti‐enterotoxic activity.
Production of Cell‐Bound Proteinase by Lactobacillus bulgaricus and its Location in the Bacterial Cell
Authors: ARGYLE P. J. , MATHISON G. E. , CHANDAN R. C.
Published: March 2008

Lactobacillus bulgaricus NCDO 1489 produced a single, cell‐bound proteinase during growth on nutrient medium at 45°C. Proteinase activity was optimal at 45–50°C and pH 5.2–5.8. and was inhibited by chelating agents. The enzyme was mainly associated with the cell envelope but could be liberated from cells under conditions favouring autolysis or by treatment of the cells with lysozyme. Its relation to the growth of the organism in milk and possible role in formation of fermented milk products are discussed.
Inhibition of Aflatoxin Accumulation in Smoked Substrates
Authors: ARSECULERATNE S. N. , SAMARAJEEWA U. , WELIANGA L. V.
Published: March 2008

The pattern of fungal colonization on processed (smoked) copra kernels and the levels of aflatoxin detected in copra and in culture of Aspergillus flavus on fresh coconut suggested that aflatoxin accumulation was inhibited by the smoking process. This paper describes the study of the smoking process under laboratory conditions with fresh coconut and potato dextrose broth; aflatoxin accumulation was found to be significantly or totally inhibited in both smoked coconut and in smoked broth. Mycelial growth was inhibited to a lesser degree.

On account of the urgent need for simple, cheap and efficent techniques for the processing and safe storage of food substrates especially in poor tropical countries, we suggest that the smoking process deserves study under industrial conditions for the protection of other agricultural food crops (e.g. groundnut) as well.
A Comparison of the British Pharmacopoeia (1973) and United States Pharmacopeia (1975) Methods for Detecting Pseudomonads
Authors: HART A. , MOORE K. E. , TALL D.
Published: March 2008

The British Pharmacopoeia (Anon. 1973) test for contamination by pseudomonads and the United States Pharmacopeia (Anon. 1975) test for the detection of Pseudomonas aeruginosa have been evaluated using type cultures representative of a wide spectrum of Pseudomonas spp. Media containing cetrimide are recommended by both Pharmacopoeias for the detection of pseudomonads. Of the 28 strains tested only five were detected by the BP method and 11 by the USP method. However, only one strain of P. aeruginosa failed to be detected using the USP method. A correlation between m.i.c. values for cetrimide and detection of the organisms was noted. The BP method failed to detect organisms with m.i.c. values of ± 0.03% whilst the USP method did not detect strains with m.i.c. values ± 0.015%.
Adenosine Triphosphate in the Bovine Rumen During Maximum Nutrient Supply and Starvation
Authors: WOLSTRUP JENS , JENSEN KURT
Published: March 2008

The concentration of adenosine triphosphate (ATP) in rumen fluid from heifers fed high levels of nutrients continuously and after 12–24 h starvation has been determined in order to examine the influence of different physiological conditions. The conventional parameters for characterizing the rumen fermentation have been applied to control the effect of a different nutrient supply. The mean concentration of ATP, determined by the luciferin‐luciferase assay, was 55.3 mg ATP/l rumen fluid in a heifer fed continuously, twice as much as found in a starved heifer. The mean ratio of biomass/ATP changed from 683 at the high level of energy intake to 1208 in the period of starvation. Consequently, the concentration of ATP in the rumen micro‐organisms is markedly influenced by nutritional conditions. Finally, the applicability of ATP determinations in rumen microbiology is discussed.
An Evaluation of Commercial Thiosulphate Citrate Bile Salt Sucrose Agar (TCBS)
Authors: NICHOLLS K. M. , LEE J. V. , DONOVAN T. J.
Published: March 2008

The recovery of vibrios, in particular Vibrio cholerae, non‐cholera vibrios and V. parahaemolyticus, on four brands of TCBS has been compared. The selectivity of the media was also compared. Eiken TCBS performed best in our tests but was closely followed by Oxoid TCBS.
The Aerobic Bacterial Flora of the Anal Sac of the Red Fox
Authors: GOSDEN PAULINE E. , WARE G. C.
Published: March 2008

Sixty‐five samples of anal sac fluid taken aseptically from 20 living Red Foxes (Vulpes vulpes) yielded a wide range of bacterial species when cultured aerobically. Only Proteus and Streptococcus spp. were regularly present in large numbers even though large numbers of Escherichia coli were present in the foxes’faeces.
Oxidation of Arsenite by a Soil Isolate of Alcaligenes
Authors: OSBORNE F. H. , EHRLICH H. L.
Published: March 2008

A strain of Alcaligenes, isolated from soil and grown in nutrient broth in the presence of arsenite, possessed the ability to oxidize arsenite to arsenate. Washed cell suspensions consumed one‐half mol of oxygen/mol of arsenite and produced arsenate. The optimum pH for arsenite oxidation was 7.0. The Km for arsenite was 1.5 × 10‐4 M and Vmax was 6.7 μl of oxygen/min. The arsenite‐oxidizing enzyme system was induced by growth in arsenite. Response of the arsenite‐oxidizing enzyme system to respiratory inhibitors suggested that electrons resulting from arsenite oxidation by an oxido‐reductase with a bound flavin are transferred via cytochrome c and cytochrome oxidase to oxygen. The presence of the cytochromes in crude extract was confirmed by spectral measurements.
Large‐scale Harvesting and Concentration of Bacteria by Tangential Flow Filtration
Authors: REID D. E. , ADLAM C.
Published: March 2008

A self‐contained tangential flow filtration system was used to harvest, concentrate and wash suspensions of corynebacteria aseptically.

Using two filter stacks each containing 15 × 0.6 nm filters, 60 l of culture could be concentrated to 8 l, thrice washed and harvested within a working day.

Organism washing was efficient and no impairment of activity of harvested organisms was seen.

Tangential flow filtration provides a simple rapid method for harvesting bacteria and their extracellular products aseptically from cultures grown on a production scale.
An Automatic Apparatus for the Evacuation and Filling of Several Anaerobic Jars Simultaneously
Authors: IMPEY C. S. , PRESCOTT E. H. A.
Published: March 2008

An apparatus is described that will automatically evacuate and refill with gas up to four standard anaerobic jars, simultaneously.

The control valves can be switched manually when large anaerobic vessels, such as modified milk churns are in use.
Evaluation of Media for Counting Viable Bacteria in Estuaries
Authors: GOULDER R.
Published: March 2008

Plate counts of viable bacteria in estuarine water samples were made using seven standard agar media.

Highest counts were obtained on Anderson's medium which is therefore recommended for general estuarine use.

The composition of Anderson's medium was peptone 2.5 g, yeast extract 2.5 g, FePO4 0.1 g and agar 15.0 g, made up to 11 with artificial estuary water.
Microbiological Standards for Nasal Solutions
Authors: MOORE K. E. , TAYLOR J. E.
Published: March 2008

In Great Britain there are no official standards for evaluating the preservation of nasal solutions. The development of a multi‐dose nasal solution containing 2% (w/v) sodium cromoglycate provided an opportunity for devising suitable standards and for evaluating the selected preservative system.
The Ultrastructure of the Fungus Trichoderma viride and Investigation of its Growth on Cellulose
Authors: BERG BJÖRN , HOFSTEN ANGELICA v.
Published: March 2008

Changes in the ultrastructure of Trichoderma viride during growth in shake cultures on cellobiose and cellulose fibres were examined. Electron micrographs of thin sections of germinating conidia, septate hyphae with ascomycete pores and other cell organelles are presented. Extensive autolysis of hyphae was observed after growth for 20 h on cellobiose. The fungus grew in the lumina and within the walls of cellulose fibres. The hyphae followed the directions of the laminar structure but did not grow across them. The observations indicated that the hyphae penetrated the fibres by causing cracks and by dissolving enzymatically the cellulose.
The Occurrence of Aflatoxin‐producing Strains of Aspergillus flavus in the Mould Floras of Ground Spices
Authors: FLANNIGAN B. , HUI S. C.
Published: March 2008

All of 20 different ground spices and three mixtures purchased locally were significantly contaminated by bacteria, and only cloves were free of moulds, but thermophilic actinomycetes were isolated from only six spices. In general, the mould floras were dominated by Aspergillus spp.: A. glaucus (group) and A. niger being the most common. A. flavus was found in 14 spices and seven of 24 strains examined produced aflatoxins in vitro. Whole ginger and Jamaica, red and white peppers supported growth of A. flavus strains and production of aflatoxins.
Lysis by β‐lactam Antibiotics: Structure‐activity Relationships in the Cephalosporins
Authors: HAMILTON‐MILLER J. M. T.
Published: March 2008

The ability of several cephalosporins to lyse Staphylococcus aureus and Escherichia coli has been studied. Cephradine and cephalexin, which have a methyl substituent at C‐3, did not lyse E. coli, but a third 3‐methyl compound, deacetoxycephalothin, caused bacteriolysis. All the compounds tested (including cephalexin and cephradine) lysed Staph. aureus. The minimum lytic concentration of a cephalosporin for E. coli often exceeded its minimum inhibitory concentration, while for staphylococci this was never the case.
An Evaluation of the ‘GasKit’Disposable Hydrogen and Carbon Dioxide Generator for the Culture of Anaerobic Bacteria
Authors: FERGUSON I. R. , PHILLIPS K. D. , WILLIS A. T.
Published: March 2008

The new GasKit disposable hydrogen and carbon dioxide generator is a reliable and convenient method for producing anaerobiosis in standard anaerobic jars when compared with a conventional procedure. The generator produces an atmosphere containing 10–12% carbon dioxide by volume which is satisfactory for the culture of exacting anaerobes.
Comparison of the Biochemical Properties of Bacteroides melaninogenicus from Human Dental Plaque and Other Sites
Authors: SHAH H. N. , BOWDEN G. H. , HARDIE J. M. , WILLIAMS R. A. D.
Published: March 2008

A total of 45 strains of black‐pigmented bacteroides, including Bacteroides melaninogenicus subsp. melaninogenicus, Bacteroides melaninogenicus subsp. intermedius and Bacteroides melaninogenicus subsp. asaccharolyticus, have been examined for morphological and physiological characteristics. They were also tested for the range of acidic metabolites, the typical basic amino acid of the mucopeptide, the base composition of DNA, the electrophoretic mobility of malate dehydrogenase and the susceptibility to certain antibiotics. The subspecies most commonly isolated from supragingival human dental plaque are B. melaninogenicus subsp. intermedius and B. melaninogenicus subsp. melaninogenicus. A list of tests for the differentiation of the three subspecies is given, but the separation of B. melaninogenicus subsp. asaccharolyticus from the other two subspecies of B. melaninogenicus is nevertheless recommended.
SHORT COMMUNICATIONAn Adaptable System for Timed Aseptic Sampling and Storage of Microbial Cultures
Authors: NEWMAN P. B.
Published: March 2008

Equipment is described which permits aseptic sampling of microbial cultures and the subsequent controlled temperature storage of these samples.

The system is fully automated, has a flexible sampling programme (10 min—2 days’interval between samples) and a capacity of up to 300 × 15 ml samples.

It is inexpensive to construct and sufficiently flexible to permit direct integration with standard monitoring and/or automated analytical systems.
An Electron Microscope Study of Bacteroides nodusus: Ultrastructure of Organisms from Primary Isolates and Different Colony Types
Authors: SHORT J. A. , THORLEY C. M. , WALKER P. D.
Published: March 2008

Examination of the ultrastructure of strains of Bacteroides nodosus isolated from cases of ovine foot‐rot shows the organism to be highly piliated on primary culture. On subculture in the laboratory two colony types characterized by a high and low degree of piliation can be demonstrated. In agglutination tests the interaction of pili with antibody is responsible for high titre homologous agglutination. Low titre heterologous agglutination appears to be due to other surface antigens. These findings are discussed in relation to the pathogenicity of the organism.
The Distribution of O‐antigen Types of Escherichia coli in Normal Calves, compared with Man, and their R plasmid Carriage
Authors: HOWE KATHERINE , LINTON A. H.
Published: March 2008

The distribution of O‐antigen types of Escherichia coli in calves over a ten‐month period has been determined. A total of 400 calves from separate farms located over a wide area of England and Wales have been surveyed. Of the 148 O‐types recognized, 93 were found in calves, compared with 107 in a previous survey in man; 42 of these were common to both hosts. In calves 60% of isolates were resistant to at least one antibiotic. Of these, 71% belonged to ten O‐types, 9 of which were found in man. It is concluded that calves form a potential reservoir of R plasmid carrying E. coli.
Enrichment in Muller‐Kauffmann's Broth and Rappaport's Broth from Buffered Peptone Water in the Isolation of Salmonellae from Minced Meat
Authors: VASSILIADIS P. , PAPADAKIS J. A. , KARALIS D. , TRICHOPOULOS D.
Published: March 2008

Four hundred and ninetysix samples of minced meat were examined for the presence of salmonellae. The methods of isolation used in the study were: (a) the standardized direct technique of enrichment in Muller‐Kauffmann's broth incubated at 43· for 24 and 48 h, described by Edel & Kampelmacher (1969), (b) secondary enrichment in Rappaport's broth from the former medium after 24 h incubation, and (c) pre‐enrichments in buffered peptone water incubated at 37·, followed by enrichments in Muller‐Kauffmann's and in Rappaport's broth. These last procedures resulted in the higher rates of isolation of salmonellae with a slight, but not statistically significant, superiority of the enrichment in Rappaport's medium.
Minimal Medium Recovery of Thermally Injured Salmonella senftenberg 4969
Authors: WILSON JENNIFER M. , DAVIES R.
Published: March 2008

Exposure of Salmonella senftenberg 4969 to sublethal heating in phosphate buffer, pH 7·0, at 52· produced thermally injured cells characterized by their relative inability to form colonies on trypticase soy yeast extract agar compared to minimal medium (M9) agar. During subsequent incubation at 37· in liquid media, more injured cells were capable of repair in M9 than in nutrient media used for pre‐enrichment purposes. M9 was superior to lactose broth as a liquid holding medium to restore the ability of injured cells to grow on both rich and selective agar media. The addition of food products produced a more favourable environment for the repair of thermally injured cells in M9 rather than lactose broth. Pre‐enrichment in M9 was 100 times more effective than using lactose broth as the preliminary step in the detection of S. senftenberg in laboratory pasteurized liquid egg albumen.
Phytotoxicity of Acetic Acid Produced in the Anaerobic Decomposition of Wheat Straw
Authors: LYNCH J. M.
Published: March 2008

Wheat straw was subjected to aerobic and anaerobic decomposition in suspensions of soil. The products of the aerobic process stimulated the root extension of barley seedlings, whereas the anaerobic fermentation yielded products which inhibited growth. Acetic acid was the phytotoxin present in the greatest amount.
Dry‐heat Resistance of Bacillus subtilis Spores in Contact with Serum Albumin, Carbohydrates or Lipids
Authors: MOLIN G.
Published: March 2008

The apparent dry‐heat resistance of B. subtilis var. niger spores in contact with serum albumin, certain carbohydrates or lipids, was determined in an open test system. The resistance, in terms of D160‐value, was significantly increased by sucrose or serum albumin and decreased by glucose or fructose. The D160‐value of spores heated in contact with olive oil and triolein was about the same as that of the control spores (clean spores). The D160‐value of spores in soybean oil, tricaprin or trilaurin was, however, somewhat higher than that of the control spores. The D160‐value for spores heated in different lipids increased in the order: olive oil < triolein < soybean oil < tricaprin < trilaurin. The z‐value was not significantly influenced by any of the tested substances, i.e. fructose, sucrose, olive oil, soybean oil, tricaprin or trilaurin.
A Synthetic Medium for Comparative Nutritional Studies of Lactobacilli
Authors: LEDESMA O. V. , DE RUIZ HOLGADO AÍDA P. , OLIVER G. , GIORI GRACIELA S. DE , RAIBAUD P. , GALPIN J. V.
Published: March 2008

The composition of a synthetic medium supporting the growth of lactobacilli is given (Table 1). The medium, containing glucose, amino acids, vitamins, mineral salts, purines and pyrimidines, allows the study of nutritional requirements of different strains of lactobacilli under identical environmental conditions. It was found that all the strains tested needed L‐glutamic acid, L‐valine and L‐leucine, and a group of them also required L‐arginine, L‐tyrosine and L‐tryptophan. Some strains required vitamins, e.g. L. bulgaricus (pantothenic acid), L. fermenti (pantothenic acid and niacin). These results are compared with those found by others employing different media.
Studies on the Multiplication of Salmonellae in Various Enrichment Media at Different Incubation Temperatures
Authors: SCHOTHORST M. VAN , LEUSDEN F. M. VAN , JEUNINK J. , DREU J. DE
Published: March 2008

Several selected Salmonella strains did not multiply in tetrathionate brilliant green bile medium when the inoculum was small and the medium was incubated at 43° C. Gradual heating from 20° to 43° C and dilution of the medium with buffered peptone water (1:10) containing egg yolk did not decrease its inhibitory properties. It became less inhibitory, however, after the growth of other Enterobacteriaceae. These findings stress the advantage of using non‐selective pre‐enrichment since in that case the Muller‐Kauffmann tetrathionate broth will be inoculated with a large number of salmonellae and other Enterobacteriaceae thus facilitating the isolation of the former.
Inactivation of Salmonellae on Chilled and Deep Frozen Broiler Carcasses by Irradiation
Authors: MULDER R. W. A. W. , NOTERMANS S. , KAMPELMACHER E. H.
Published: March 2008

Chilled and deep‐frozen broiler carcasses were examined for total counts of salmonellae using pooled samples taken from 76 batches each of five birds. By means of a most probable number technique (MPN) it was found that counts expressed/100 g of skin or /500 ml of thaw water varied between < 2 and 1400 with 90% being < 100. Irradiation of carcasses using a dose of 250 krad was found to be highly effective in destroying salmonellae whether the birds had been chilled or deep‐frozen.
Susceptibility of Strawberry Varieties to Post‐harvest Fungal Spoilage
Authors: DENNIS C. , DAVIS R. P.
Published: March 2008

The susceptibility of strawberry fruits from eleven varieties, Cambridge Favourite, Cambridge Vigour, Cambridge Prizewinner, Red Gauntlet, Chanil, Domanil, Grandee, Litessa, Tamella. Senga Gigana and Precosana, to post‐harvest spoilage fungi was investigated over the 1974 and 1975 seasons. Although the fruit from the different varieties from each of two sites at each harvest was contaminated with a similar level of fungi, the pattern of development of the spoilage fungi revealed marked differences between some varieties. Botrytis cinerea and Mucor mucedo were the predominant spoilage fungi on all varieties with Rhizopus sexualis and R. stolonifer being of minor importance. The relative importance of these fungi changed on all varieties as the season progressed, although to a different degree according to variety, site and season. Cambridge Vigour, Senga Gigana, and Chanil were the most susceptible varieties, while Red Gauntlet was the most resistant, especially to the Phycomycetes.
Attempted Elimination of Plasmid‐determined Haemolysin, K88 Antigen and Enterotoxin from Escherichia coli Pathogenic for Pigs
Authors: MITCHELL I. DE G. , KENWORTHY R.
Published: March 2008

The plasmid‐borne gene for haemolysin (hly+) was most easily cured with inhibitors of RNA transcription, whereas DNA inhibitors of replication were most effective against the determinant for K88 antigen (K88+). Transitory removal of the enterotoxic determinant (ent+) was achieved with both RNA and DNA inhibitors. It is suggested that ent+ might be chromosomally determined as well as plasmid‐borne in pathogens.
The Classification of Bacteroides melaninogenicus and Related Species
Authors: HOLBROOK W. P. , DUERDEN B. I. , DEACON A. G.
Published: March 2008

One hundred and seventy‐five strains of Bacteroides melaninogenicus, 17 strains of B. oralis and six strains of B. ochraceus were studied in a series of biochemical, chemical tolerance and antibiotic disc resistance tests and by the gas‐liquid chromatographic analysis of the acid end products of metabolism. Strains of B. melaninogenicus ss. asaccharolyticus formed a distinct group with clear differences from other B. melaninogenicus strains. B. melaninogenicus ss. intermedius strains formed a homogeneous group that could be readily identified. B. ochraceus was distinguished from other Bacteroides spp. by its ability to grow in air enriched with CO2. Bacteriodes melaninogenicus ss. melaninogenicus and B. oralis gave very similar patterns of results with the tests used and invariably were indistinguishable; the capacity to produce black‐pigmented colonies on blood‐containing media may not be a valid criterion for dividing these similar strains into two species.
Rapid Concentration of Bacteriophages from Aquatic Habitats
Authors: PRIMROSE S. B. , DAY M.
Published: March 2008

Using a simple concentration technique, 70 different bacteriophages were isolated from river water in a single step. Some novel applications of this technique are discussed.
Microbial Ethanol, Yeasts and Coliform Bacteria in the Stomachs of Milk Fed Calves
Authors: WHITE R. W.
Published: March 2008

The frequent occurrence of Torulopsis glabrata in calf rumen is confirmed.

The presence of this organism is not necessarily accompanied by ethanol production.

Ethanol is frequently found in the rumen of calves in the absence of T. glabrata.

In the absence of glucose the presence of ethanol in the rumen of young animals can be produced from lactose by a coliform organism.
Floating‐loop Replica‐plating Device
Authors: WIBERG J. S.
Published: March 2008

The main feature of this device is its ‘floating loops’, which are thin wires formed into loops at one end and mounted in a frame such that the wires are free to move up and down. This feature was incorporated into the ‘applicator’devised by Tarr (1958) for phage‐typing, but has not been as widely used as it merits. The present device was developed independently, without knowledge of Tarr's applicator, and is described here partly to emphasize the advantages of floating loops, and partly to offer an alternative to Tarr's device, both in design and in usage.

Floating loops confer two main advantages over other types of device that pick up droplets of organism suspensions on the ends of rigidly mounted metal rods: (a) a more uniform volume of suspension is delivered, and (b) the loops do not cut into the soft agar in the acceptor Petri dish, since they are very light and ‘float’on the agar.

The device applies 56 standard spots of phage to the surface of seeded agar plates; it has performed satisfactorily in thousands of tests over several years.
Enhancement of the Sensitivity of the Limulus Assay for the Detection of Gram Negative Bacteria
Authors: COATES D. A.
Published: March 2008

In the Limulus pyrogen assay a linear relationship has been demonstrated between optical density and viable cell number of the strains of Gram negative bacteria studied.

When the bacteria are suspended in a solution of 0.9% saline and 10‐5 M‐ethylenediamine‐tetra‐acetic acid (EDTA) the sensitivity of the assay is markedly improved and the variation between different species or strains is greatly reduced.

The Limulus assay is able to detect fewer than 103 of the least reactive Gram negative bacteria studied within 1 h. It is being developed as a rapid method for detecting Gram negative contamination in raw materials and products.
The Effect of Storage in Various Gaseous Atmospheres on the Microflora of Lamb Chops Held at—1°C
Authors: NEWTON K. G. , HARRISON J. C. L , SMITH K. M.
Published: March 2008

The effect of different gaseous atmospheres on the development of the bacterial flora on lamb chops stored at –1°C was examined. The atmospheres were air, nitrogen, hydrogen, and mixtures of air + carbon dioxide, oxygen + nitrogen, oxygen + carbon dioxide, nitrogen + carbon dioxide and hydrogen + carbon dioxide (gas ratio = 80:20, v/v). Storage life of chops ranged from two weeks in air to eight weeks in oxygen‐free atmospheres. At the end of storage life Microbacterium thermosphactum was present as a major constituent of the bacterial flora in all atmospheres. In oxygen + carbon dioxide it was the predominant organism. In all other oxygen containing atmospheres, Pseudomonas spp. made up a large proportion of the flora. Strains of Enterobacteriaceae occurred in low‐oxygen and oxygen‐free atmospheres, and Lactobacillus spp. occurred in oxygen‐free atmospheres.
The Limulus Lysate Endotoxin Assay as a Test of Microbial Quality of Ground Beef
Authors: JAY J. M.
Published: March 2008

The Limulus lysate test (LLT) for endotoxin assay has been found to be an excellent, simple and rapid test of microbial quality of refrigerated ground beef. In fresh ground beef held at 5°C for 7–12 d, LLT titres increased from 102–105 and correlated very highly with extract‐release volume (ERV) data and total viable Gram negative counts at both 5° and 30°C. The LLT was negative for fresh beef containing low numbers of bacteria and on aged beef in the absence of increasing numbers of Gram negative bacteria. Of 14 Gram negative meat isolates, all gave a positive LLT while none of eight miscellaneous Gram positive bacteria did. The use of this test provides objective information on the microbial quality of fresh refrigerated ground meats in 1 h. Based upon this study, it is suggested that a 0·1 ml inoculum from a 103 dilution of good quality ground beef should produce a negative lysate test and thus serve as an additional rapid screening test of meat microbial quality.
The Microbiological Basis of a Method for Palm Wine Preservation
Authors: OKAFOR N.
Published: March 2008

A method has been developed which preserves palm wine for at least six months and possibly for longer.

Its basis is to pasteurize the supernatant of centrifuged palm wine with 0·05% sodium. bisulphite.
Experimental Diarrhoea in Human Volunteers Following Oral Administration of Clostridium perfringens Enterotoxin
Authors: SKJELKVÅLE REIDAR , UEMURA TAKASHI
Published: March 2008

Peroral administration of purified enterotoxin to human volunteers provoked diarrhoea and abdominal pain, symptoms identical with those encountered in outbreaks of Clostridium perfringens food poisoning. Eight milligrams of enterotoxin caused diarrhoea in one of two volunteers. All of five subjects given 10 and 12 mg of purified enterotoxin or crude enterotoxin developed the classical symptoms of this food poisoning. Passive haemagglutination anti‐enterotoxin titres in serum increased in only 5 of 9 volunteers after exposure to enterotoxin. As such levels of anti‐enterotoxin can be detected in normal serum samples, titration of anti‐enterotoxin may be of little use in diagnosing Cl. perfringens food poisoning. Enterotoxin was detected in all diarrhoeal faecal specimens, and the enterotoxin level varied from 0·2–16 μg/g. Detection of enterotoxin in diarrhoeal faeces may be the most reliable procedure in diagnosing outbreaks of Cl. perfringens food poisoning.
Influence of Temperature and Method of Reconstitution on the Standard Plate Count of Casein and Caseinates
Authors: COOKE B. C.
Published: March 2008

Sample solubility, in addition to method and temperature of reconstitution was found to affect the standard plate count of casein. The best combination for recovery of bacteria from casein and caseinates was pre‐warming the buffer to 45 °C and the ‘Stomacher’used for reconstitution.
Suitability of Different Bacterial Groups for Determining Faecal Contamination During Post Scalding Stages in the Processing of Broiler Chickens
Authors: NOTERMANS S. , VAN LEUSDEN F. M. , VAN SCHOTHORST M.
Published: March 2008

Several bacterial groups were tested for their suitability in determining faecal contamination of carcasses during those stages in poultry processing which follow scalding.

Counts of Enterobacteriaceae obtained with the ‘skin‐maceration’method of sampling gave a reliable indication of faecal contamination only when the birds had been scalded at 60° C or above. With lower scald temperatures, none of the bacterial groups tested was found to be suitable as an index of faecal contamination during subsequent processing.
Diaminopimelic Acid Synthesis in Cultures of an Escherichia coli Double Auxotroph: Effects of Cultural Conditions
Authors: ABDULLAH J. SH. , GOEL A. K. , HALL A. N.
Published: March 2008

The metabolic response to L‐lysine of Escherichia coli ATCC 13002, a lysine‐histidine double auxotroph, has been examined in a synthetic medium containing sucrose. In shaken cultures largest amounts of extracellular DAP were produced with an initial lysine concentration of 7·5 mg/1 and in static cultures of 2·5 mg/1. Considerably smaller amounts of DAP accumulated under stationary conditions. In cultures shaken for 20 and 43 h there was an overall decrease in the yields of DAP, expressed in terms of cell biomass and of sucrose consumed, as the initial concentration of lysine was increased from 0·75 mg/1 in steps up to 25 mg/1. The regulatory effect of lysine on DAP production was also observed when lysine was supplied to cultures at a constant rate employing diffusion capsules.