ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1983.tb02642.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1983.tb02643.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Twenty‐one strains ofRenibacterium salmoninarumwere degraded by acid methanolysis and the non‐hydroxylated fatty acid esters released examined by thin‐layer and gas chromatography. The fatty acid profiles were composed almost exclusively of methyl‐branched fatty acids with 12‐methyltetradecanoic (anteiso‐C15), 13‐methyltetradecanoic (iso‐C15) and 14‐methylhexadecanoic (anteiso‐C17) as major components. Polar lipids of the test strains were examined by two‐dimensional thin‐layer chromatography. All of the organisms possessed very characteristic polar lipid patterns consisting of diphosphatidylglycerol, two major and six or seven minor glycolipids, and two unidentified minor phospholipids. In all cases the major menaquinone components consisted of unsaturated menaquinones with nine isoprene units. The lipid data support the integrity of the genusRenibacteriumand can be used to separate it fromCorynebacteriumand from coryneform bacteria which also contain lysine in

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1983.tb02644.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The resistance of bacterial spore monitors is markedly influenced by the environmental conditions existing during development of the spores and, subsequently, in the preparation and evaluation of the monitor. Sporulation medium, suspending medium, pasteurization and storage conditions influence resistance of spores ofBacillus subtilisvar.nigerto ethylene oxide, but incubation temperature and age of sporulating culture appear to be unimportant. The conditions under which the spore suspension is dried on the supporting medium of the monitor exerts a major influence on resistance. Spores exposed to ethylene oxide are abnormally susceptible to damage by shaking with Ballotini, a method frequently used to recover spores from monitors. Nutritional conditions, pH and temperature of incubation influence the ability of survivors to form colonies on solidified media.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1983.tb02645.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Herring fillets from the Baltic Sea were stored in glass vessels in air, nitrogen or carbon dioxide (CO2) at 2°C and the microbial development was studied. The microbiological shelf‐life of the herring (the time to reach 107organisms/g) was prolonged by a factor of 3.5 in CO2as compared to air. The corresponding factor in nitrogen was 1.5. The microflora of fresh and spoiled herring was classified. The initial microflora was dominated by coryneforms,Flavobacteriumspp.,Moraxella‐like organisms andPseudomonasspp. The spoilage‐flora in air (after 9 d) was dominated byPseudomonasspp. andMoraxella‐like organisms, and in nitrogen (14 d) Enterobacteriaceae, Vibrionaceae andLactobacillusspp. were dominant. HomofermentativeLactobacillusspp. were the only organisms isolated from fillets stored in CO2(28 d). It was concluded that storing fresh fish in pure CO2at low refrigeration temperatures is a method with industrial potential. The method (1) improves the microbiological stability and (2) reduces the microbiological health hazards of

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1983.tb02646.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Saccharomyces dairensisandSacch. exiguuswere isolated as the spoilage flora of coleslaw stored at 5° and 10°C. The growth of these yeasts in mixtures of mayonnaise with vegetable was inhibited by onion. Mayonnaise alone killed the yeasts, primarily because of its content of acetic acid and this effect increased as the temperature was increased and as the pH was decreased. Addition of cabbage or carrot tissue removed the lethal effect of mayonnaise and allowed spoilage, by absorbing acetic acid and increasing the p

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1983.tb02647.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1983.tb02648.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

VariousBacteroidesspp. were examined by physiological tests, presence of specific enzymes, antibiotic sensitivity, menaquinone composition and a few miscellaneous tests. The data matrix containing 58 strains and 55 unit characters was examined using Gower's similarity coefficients (SG) and included matching negative character states and multistate characters. The highly saccharolytic strains were separated from the less saccharolytic and non‐fermentative strains at the 55% similarity level; while at the slightly higher level of 63% strains ofCapnocytophaga(formerlyBact. ochraceus) were recovered as a compact phenon distinct from other saccharolytic species. The phenogram was divided into 6 clusters at 72% similarity level. Most of the ‘Bact. fragilisgroup’ of species clustered in one phenon whileBact. melaninogenicusssp.melaninogenicus, Bact. biviusand a new species,Bact. denticola, formed another group. Another phenon comprised the saccharolytic non‐pigmented species closely related toBact. oralissuch asBact. buccalisandBact. pentosaceus.The less saccharolytic strains ofBact. melaninogenicusssp.intermediusandBact. disienswere recovered in a distinct phenon. The low affinity (less than 55% similarity) between the two subspecies ofBact. melaninogenicusemphasised the need for reclassifying these taxa into separate species. The non‐fermentative and very weakly saccharolytic strains formed good taxospecies. The separation of this cluster into three subclusters is in excellent agreement with chemotaxonomic data now

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1983.tb02649.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The upper limiting temperature of growth ofStaphylococcus aureusMF31 in heart infusion broth (HI) was about 44°C but addition of monosodium glutamate (MSG) and soy sauce permitted the organism to grow above this temperature. This effect is similar to that of NaCl. Tomato ketchup, Worcestershire and HP sauces added to HI did not allow growth at the non‐permissive temperature of 46°C but death was delayed.Staphylococcus aureusdied in unsupplemented chicken meat slurry at 46°C but grew at 48°C in slurry supplemented with 5.8% NaCl and survived incubation for 18 h at 50°C in slurry supplemented with 5.8% NaCl and 5% MSG. Cultures grown at 37°C had aD60value of 2 min in 50 mmol/l Tris (pH 7.2) buffer. Cultures grown at 46°C in HI containing 5.8% NaCl had aD60value of 8 min in Tris buffer. Addition of 5.8% NaCl plus 5% MSG to the buffer increased theD60by a factor of about 7 for both cultures. In storage experiments at room temperature, the culture grown at 37°C and at 46°C plus 5.8% NaCl died at about the same rate in salami. In milk powder, however, the count of 37°C culture decreased from 109/g to 106/g in 5 weeks while the count of 46°C culture remained unchanged. In cottage cheese, freeze‐dried rice and macaroni, the 37°C cultures also died more rapidly. It is suggested that cultures grown at 46°C plus 5.8% NaCl may be suitable for experiments with artificially co

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1983.tb02650.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The survival ofSalmonella typhimuriumwas investigated in acidogenic, anaerobically fermented pig wastes and in synthetic media, each containing volatile fatty acids (VFA).Salm. typhimuriumsurvived at pH 6·8, but not at pH 4·0, when incubated at 37°C for 24 h in either fermented or synthetic medium containing VFA. The minimum inhibiting concentration of VFA forSalm. typhimuriumafter 48 h incubation at 30°C at pH 4·0 was 0·03 mol/l and forEscherichia coliit was 0·09 mol/l. Fermented pig wastes in a digester, maintained at pH 5·9, were inoculated withSalm. typhimuriumand then incubated at 37°C for 24 h. The pH was adjusted to either 4·0 or 5·0 and after a further 48 h at 30°C,Salm. typhimuriumsurvived at pH 5·0 but not at pH 4·0. It was concluded that pH is critical in determining the survival of this organism in acidogenic anaerobically fermen

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1983.tb02651.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY