From field to fermentation: characterisation and application of non-dairy cultures in dairy foods

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dc.contributor.advisor McAuliffe, Olivia en
dc.contributor.advisor Kilcawley, Kieran en
dc.contributor.advisor Fitzgerald, Gerald F. en Cavanagh, Daniel 2017-01-10T13:36:47Z 2014 2014
dc.identifier.citation Cavanagh, D. 2014. From field to fermentation: characterisation and application of non-dairy cultures in dairy foods. PhD Thesis, University College Cork. en
dc.identifier.endpage 325 en
dc.description.abstract This thesis investigates the phenotypic and genotypic diversity of non-dairy L. lactis strains and their application to dairy fermentations. A bank of non-dairy lactococci were isolated from grass, vegetables and the bovine rumen. Subsequent analysis of these L. lactis strains revealed seven strains to possess cremoris genotypes which did not correlate with their observed phenotypes. Multi-locus sequence typing (MLST) and average nucleotide identity (ANI) highlighted the genetic diversity of lactis and cremoris subspecies. The application of these non-dairy lactococci to cheese production was also assessed. In milk, non-dairy strains formed diverse volatile profiles and selected strains were used as adjuncts in a mini Gouda-type cheese system. Sensory analysis showed non-dairy strains to be strongly associated with the development of off-flavours and bitterness. However, microfluidisation appeared to reduce bitterness. A novel bacteriophage, ɸL47, was isolated using the grass isolate L. lactis ssp. cremoris DPC6860 as a host. The phage, a member of the Siphoviridae, possessed a long tail fiber, previously unseen in dairy lactococcal phages. Genome sequencing revealed ɸL47 to be the largest sequenced lactococcal phage to date and owing to the high % similarity with ɸ949, a second member of the 949 group. Finally, to identify and characterise specific genes which may be important in niche adaptation and for applications to dairy fermentations, comparative genome sequence analysis was performed on L. lactis from corn (DPC6853), the bovine rumen (DPC6853) and grass (DPC6860). This study highlights the contribution of niche specialisation to the intra-species diversity of L. lactis and the adaptation of this organism to different environments. In summary this thesis describes the genetic diversity of L. lactis strains from outside the dairy environment and their potential application in dairy fermentations. en
dc.description.sponsorship Teagasc (Walsh Fellowship Programme) en
dc.format.mimetype application/pdf en
dc.language English en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2014, Daniel Cavanagh. en
dc.rights.uri en
dc.subject Lactococcus lactis en
dc.subject Taxonomy en
dc.subject Non-dairy en
dc.subject Bacteriophage en
dc.subject Genomics en
dc.title From field to fermentation: characterisation and application of non-dairy cultures in dairy foods en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Science) en
dc.internal.availability Full text available en
dc.description.version Accepted Version
dc.contributor.funder Teagasc en
dc.contributor.funder Dairy Research Trust, Ireland en
dc.description.status Not peer reviewed en Microbiology en Teagasc en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out No en
dc.thesis.opt-out false
dc.check.chapterOfThesis Chapter 5
dc.check.embargoformat E-thesis on CORA only en
dc.internal.conferring Summer 2015 en

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© 2014, Daniel Cavanagh. Except where otherwise noted, this item's license is described as © 2014, Daniel Cavanagh.
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