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dc.contributor.advisorHugo, C. J.
dc.contributor.advisorJooste, P. J.
dc.contributor.authorDe Beer, Hanli
dc.date.accessioned2018-07-26T06:53:15Z
dc.date.available2018-07-26T06:53:15Z
dc.date.issued2005-05
dc.identifier.urihttp://hdl.handle.net/11660/8975
dc.description.abstractEnglish: Microbial diversity in a food complicates the prediction or measurement of the effect of specific micro-organisms on a perishable food commodity stored under different conditions. Gram-negative yellow-pigmented colonies belonging to the Flavobacteriaceae family are often present when total numbers on food samples are investigated. Changes in the taxonomy of flavobacteria since its inception in 1923 have, however, complicated the identification of these bacteria. Many organisms previously regarded as Flavobacterium have been found to belong to several new genera in the family Flavobacteriaceae. With the introduction of a chemotaxonomic approach and molecular techniques such as rRNA sequencing, it is now possible to refine the differentiation between closely related genera. Chromosomal DNA characteristics further enhance accurate differentiation between various species. This study used a polyphasic taxonomic approach that included a combination of phenotypic and genotypic testing methods in order to characterise and classify Gram-negative yellow-pigmented strains isolated from raw chicken, red meat and fish. During this study 129 Gram-negative yellow-pigmented pure cultures were isolated from raw chicken, red meat and fish samples. Protein fingerprint profiles and long chain fatty acid analyses revealed that the majority of organisms belonged to the genus Chryseobacterium. The 16S rRNA sequence and DNA-DNA hybridisation methods were used to give the relationship between test strains and the reference strains of various species in the genus. Several isolated strains from the chicken, red meat and fish could be equated with C. balustinum (2), C. defluvii (16), C. scophthalmum (4) or C. gleum (2) strains. A few strains (9) did not show any affiliation with any reference strain. Two new Chryseobacterium species, however, have been proposed from the findings of this study namely Chryseobacterium vrystaatense sp.nov.,which is comprised of the type strain R-23566 (= LMG 22846T) and 36 strains isolated from raw chicken samples. Strains showed strong DNase- and also urease and lecithinase activity but were not capable of starch and tyrosine hydrolysis. The mol % G + C of R-23566 was 37.6 %. The second new species, Chryseobacterium piscium sp. nov., comprised four strains which were obtained from marine fish, with R-23621 as the type strain. The G + C mol % was 33.6 %. This group was psychrotrophic in that they grew within 24 hours at 4 °C but very poorly at 32 °C. In order to establish the source of potential Chryseobacterium contamination, different areas and processing stages in the chicken abattoir were sampled. Chryseobacterium species contributed to 8.3 % of the total bacterial count on whole birds in this study. It was evident that the washing processes lowered the total counts on carcasses. A significant increase in the total bacterial counts, as well as total Chryseobacterium counts was reported and Chryseobacterium species were found to represent between 20 and 25 % of the total population after portioning procedures during this study. Live chickens as source of Chryseobacterium contamination should be investigated in future.en_ZA
dc.description.abstractAfrikaans: Mikrobiologiese verskeidenheid in voedsel kommoditeite bemoeilik die voorspelling of meting van die uitwerking wat spesifieke mikro-organismes, het tydens opberging van bederfbare voedsel onder verskillende toestande. Gramnegatiewe geel gepigmenteerde kolonies, wat tot die familie Flavobacteriaceae behoort, is dikwels teenwoordig op agar-plate van totale bakterietellings van voedselmonsters. Veranderinge in die taksonomie van flavobakterieë sedert 1923, het identifikasie van hierdie bakterieë gekompliseer. Verskeie voorheen erkende Flavobacterium species behoort nou aan ander genera in die familie Flavobacteriaceae. Sedert die toepassing van ‘n chemotaksonomiese aanslag en die ontwikkeling van meer molekulêre mikrobiologiese tegnieke soos die rRNS sekwensies, was dit moontlik om onderskeid tussen nouverwante genera te tref en DNS eienskappe het akkurate onderskeiding tussen vervante spesies moontlik gemaak. Tydens hierdie studie is daar van ‘n polifasiese taksonomiese aanslag gebruik gemaak wat ‘n kombinasie van fenotipiese sowel as genotipiese tegnieke ingesluit het, ten einde geelgepigmenteerde, Gram-negatiewe isolate wat van hoender, rooivleis en vis verkry is, te klassifiseer. Tydens die studie is 129 Gram-negatiewe geel pigementbevattende reinkulture vanaf rou hoender-, vleis- en vismonsters geïsoleer. Proteien vingerafdrukprofiele en langkettingvetsuurontledings is gedoen, wat uitgewys het dat die meerderheid van die organismes aan die genus Chryseobacterium behoort. Die 16S rRNS sekwensie en die DNS-DNS hibridisasie metodes het die verwantskap tussen die isolate en die verwysingsstamme aangetoon. Etlike isolate kon as C. balustinum (2), C. defluvii (16), C. scophthalmum (4) of C. gleum (2) geidentifiseer word. ‘n Paar stamme (9) het geen noue verband met enige van die verwysingstamme getoon nie. Twee nuwe Chryseobacterium spesies is in die loop van die studie voorgestel naamlik ‘Chryseobacterium vrystaatense sp.nov.’ , bestaande uit R-23566 (= LMG 22846T) as verteenwoordigende stam, en 36 nouverwante isolate wat vanaf rou hoender geïsoleer is. Hierdie stamme vertoon sterk DNase-, asook urease- en lesitinase-aktiwiteit maar geen stysel- of tirosienhidrolise nie. Die mol % G + C van R-23566 was 37.6%. Die tweede nuwe spesies, ‘Chryseobacterium piscium sp. nov.’, bestaan uit vier isolate, afkomstig van seevis met R-23621 as die verteenwoordigende stam. Die G + C mol % was 33.6 %. Hierdie groep is meer psigrotrofies as die ander deurdat kolonies binne 24 ure by 4 °C gevorm word terwyl daar weinig groei by 32 °C voorkom. Ten einde die bron van moontlike kontaminasie gedurende prosessering te bepaal, is verskillende areas en prosesseringsstappe in die hoender abattoir bemonster. Chryseobacterium spesies verteenwoordig 8.3 % van die totale aantal organismes op hoenderkarkasse. Dit was duidelik dat die wasprosesse totale tellings op karkasse verminder. ‘n Betekenisvolle toename in die totale bakterie telling, asook die totale Chryseobacterium-telling, wat 20 en 25 % van die totale populasie op hoenderkarkasse verteenwoordig het, het na opsnyprosesse voorgekom. Lewende braaikuikens, as bron van Chryseobacteriumkontaminasie, moet in die toekoms ondersoek word.en_ZA
dc.description.sponsorshipNational Research Foundation (NRF)en_ZA
dc.language.isoenen_ZA
dc.publisherUniversity of the Free Stateen_ZA
dc.subjectFlavobacteriaceaeen_ZA
dc.subjectChryseobacteriumen_ZA
dc.subjectIsolationen_ZA
dc.subjectIdentificationen_ZA
dc.subjectTaxonomyen_ZA
dc.subjectC. vrystaatense sp. nov.en_ZA
dc.subjectC. piscium sp. nov.en_ZA
dc.subjectSourcesen_ZA
dc.subjectFood spoilageen_ZA
dc.subjectMeat -- Microbiologyen_ZA
dc.subjectBacteria -- Classificationen_ZA
dc.subjectThesis (Ph.D. (Microbial, Biochemical and Food Biotechnology))--University of the Free State, 2005en_ZA
dc.titleA taxonomic study of Chryseobacterium species in meaten_ZA
dc.typeThesisen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA


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