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dc.contributor.advisorHugo, C. J.
dc.contributor.advisorJooste, P. J.
dc.contributor.authorTsoeu, Likoti Ingrid
dc.date.accessioned2018-07-20T08:38:45Z
dc.date.available2018-07-20T08:38:45Z
dc.date.issued2009-05
dc.identifier.urihttp://hdl.handle.net/11660/8845
dc.description.abstractEnglish: Frequent reports of yellow-pigmented Gram-negative rods being encountered during routine bacteriological analyses of milk and milk products, meat, canned products and surface waters, accentuate the universal distribution of Flavobacteriaceae. Many organisms previously regarded as Flavobacterium have been found to belong to several new genera in the family Flavobacteriaceae. The introduction of a chemotaxonomic approach and molecular techniques such as rRNA sequencing, has made it possible to refine the differentiation between closely related genera. Although Flavobacteriaceae are widely distributed in soil and plants, their presence and roles in these environments has received less attention in South Africa. The first purpose of this study was to investigate the presence of Flavobacteriaceae from eight different vegetables and the surrounding soil in which the vegetables were planted; yellow pigmented Gram-negative bacteria were isolated from the samples and examined for the presence of Flavobacteriaceae. The second part of this study was to taxonomically re-define flavobacterial dairy isolates from previous studies using newer phenotypic procedures, including the BIOLOG system and also genotyping techniques such as 16S rRNA sequencing. Phenotypic tests were used for the preliminary grouping of isolates. The BIOLOG Microplate system showed that most “flavobacterial” isolates from vegetables were highly related to the genus Sphingobacterium, whereas isolates from soil were related to Chryseobacterium gleum/indologenes. Most of the dairy isolates identified with this method were closely related to the genera Chryseobacterium and Empedobacter. The 2001 database of the BIOLOG system currently in use, is however, incapable of identifying all Flavobacteriaceae genera and species since no new additions have been made and it is also not possible to manually do so. Isolates were subsequently subjected to the 16S rRNA sequencing technique which was able to verify and differentiate organisms identified by the BIOLOG Microplate system. Because of poor quality DNA, the two soil isolates could not be identified with this method. Fourteen of the 18 dairy isolates that underwent sequencing were highly related to the genus Chryseobacterium while four isolates were identified as E. brevis. The possible spoilage characteristics of the Flavobacteriaceae isolates in this study were also evaluated using the BIOLOG system. It became clear that they could utilize certain carbohydrates, carboxylic acids, amino acids and polymers that could contribute to spoilage defects of food by creating off-odours, off-tastes, sliminess and bitterness of specific foods.en_ZA
dc.description.abstractAfrikaans: Gereelde bevindings van geel gepigmenteerde Gram-negatiewe stawe gedurende roetiene bakteriologiese analises van melk en melkprodukte, vleis, geblikte produkte en oppervlakwater, beklemtoon die universele verspreiding van Flavobacteriaceae. Baie organismes voorheen bekend as Flavobacterium behoort nou aan nuwe genera in die Flavobacteriaceae familie. Die bekendstelling van ‘n nuwer chemotaksonomiese benadering en molekulêre tegnieke soos rRNA sekwensering, het dit moontlik gemaak om die onderskeid tussen naasbestaande genera te verfyn. Alhoewel Flavobacteriaceae verspreid voorkom in grond en plante, het hulle teenwoordigheid en betekenis in hierdie omgewings minder aandag geniet in Suid-Afrika. Die eerste doel van hierdie studie was om die teenwoordigheid van Flavobacteriaceae lede op agt verskillende groentes en omliggende grond waarin groente geplant was, te bepaal. Geel gepigmenteerde Gram-negatiewe bakterieë is geïsoleer en gekarakteriseer. Die tweede deel van hierdie studie was gemik op suiwelisolate uit vorige studies wat voorlopig geïdentifiseer was as C. balustinum-agtig, Empedobacter-agtig en Weeksella-agtig. ‘n Ongeïdentifiseerde SDS-PAGE groep uit so ‘n vorige studie is ook geteiken. In hierdie deel van die huidige studie is die BIOLOG fenotipiese sisteem en 16S rRNA sekwensering toegepas op die bakteriestamme. Gewone fenotipiese toetse is vir die voorlopige groepering van isolate gebruik. Die BIOLOG Microplate sisteem is vir meer gevorderde identifikasie gebruik en dit het getoon dat die meeste isolate vanaf die groentesoorte hoogs verwant was aan die genus Sphingobacterium, terwyl isolate uit die grond verwant was aan Chryseobacterium gleum/indologenes. Die meeste van die suiwelisolate wat met hierdie metode geïdentifiseer is, was na-verwant aan die Chryseobacterium en Empedobacter genera Die 2001 databasis van die BIOLOG sisteem tans in gebruik, is egter onvoldoende om nuwer Flavobacteriaceae genera en species te identifiseer aangesien die stelsel nie ontwerp is om met nuwer data opgegradeer te word nie. Isolate is daarna aan 16S rRNA sekwensering onderwerp wat instaat was daartoe om die organisms wat met die BIOLOG sisteem geïdentifiseer is, te verifieer en te differensieer. As gevolg van ‘n swak gehalte DNA van die twee grond isolate, kon dit nie met hierdie metode identifiseer word nie. Veertien van die 18 suiwelisolate wat sekwensering ondergaan het, was hoogs verwant aan die Chryseobacterium genus terwyl vier isolate as E. brevis identifiseer is. Derdens is die moontlike bederf eienskappe van die Flavobacteriaceae isolate in hierdie studie ge-evalueer met behulp van die BIOLOG sisteem. Dit het duidelik geword dat die isolate spesifieke koolhidrate, karboksielsure, aminosure en polimere kon gebruik wat kon bydra tot gebreke in voedsel deur die onstaan van afgeure, afsmake, slymerigheid en bitterheid van spesifieke voedsel te veroorsaak.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.subjectSpoilageen_ZA
dc.subjectTaxonomyen_ZA
dc.subjectDairyen_ZA
dc.subjectVegetablesen_ZA
dc.subjectSoilen_ZA
dc.subjectDissertation (M.Sc. (Food Science))--University of the Free State, 2009en_ZA
dc.titleThe taxonomy and spoilage characteristics of Flavobacteriaceae isolates from fooden_ZA
dc.typeDissertationen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA


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