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

Cavanagh, Daniel

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

dc.check.chapterOfThesis	Chapter 5
dc.check.embargoformat	E-thesis on CORA only	en
dc.check.opt-out	No	en
dc.check.reason	This thesis is due for publication or the author is actively seeking to publish this material	en
dc.contributor.advisor	McAuliffe, Olivia	en
dc.contributor.advisor	Kilcawley, Kieran	en
dc.contributor.advisor	Fitzgerald, Gerald F.	en
dc.contributor.author	Cavanagh, Daniel
dc.contributor.funder	Teagasc	en
dc.contributor.funder	Dairy Research Trust, Ireland	en
dc.date.accessioned	2017-01-10T13:36:47Z
dc.date.issued	2014
dc.date.submitted	2014
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.description.status	Not peer reviewed	en
dc.description.version	Accepted Version
dc.format.mimetype	application/pdf	en
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.identifier.uri	https://hdl.handle.net/10468/3458
dc.language	English	en
dc.language.iso	en	en
dc.publisher	University College Cork	en
dc.rights	© 2014, Daniel Cavanagh.	en
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/	en
dc.subject	Lactococcus lactis	en
dc.subject	Taxonomy	en
dc.subject	Non-dairy	en
dc.subject	Bacteriophage	en
dc.subject	Genomics	en
dc.thesis.opt-out	false
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
ucc.workflow.supervisor	g.fitzgerald@ucc.ie