Listeria monocytogenes in ready-to-eat food and antimicrobial effect of plant additives in meat products
| dc.contributor.advisor | Roasto, Mati (advisor) | |
| dc.contributor.advisor | Meremäe, Kadrin (advisor) | |
| dc.contributor.advisor | Mäesaar, Mihkel (advisor) | |
| dc.contributor.author | Koskar, Julia | |
| dc.contributor.department | Institute of Veterinary Medicine and Animal Sciences | eng |
| dc.contributor.other | Uyttendaele, Mieke (opponent) | |
| dc.date.accessioned | 2026-09-15T11:11:39Z | |
| dc.date.available | 2026-09-15T11:11:39Z | |
| dc.date.defensed | 2026-08-26 | |
| dc.date.issued | 2026 | |
| dc.description | Doctoral Thesis in Food Science. | eng |
| dc.description | Doktoritöö toiduteaduse erialal. | est |
| dc.description.abstract | ABSTRACT. Listeria monocytogenes is a foodborne pathogen that poses a significant public health risk, particularly in the consumption of long shelf-life ready-to-eat foods that do not require additional heat treatment. The ability of this pathogen to remain viable and grow at refrigeration temperatures is especially hazardous for vulnerable consumer groups. Increasing consumer demand for natural and minimally processed foods necessitates the identification of alternatives to synthetic food preservatives. This thesis analysed the occurrence of L. monocytogenes in ready-to-eat foods produced in Estonia and assessed the effects of plant-based powders and their mixtures on microbial growth in both raw and heat-treated minced meat samples. The results indicated that contamination of ready-to-eat foods with L. monocytogenes was generally low, pathogen was detected in 3.6% of samples (n = 30,016). The pathogen was most frequently found in fish products, particularly in lightly salted and cold-smoked fish. Although the counts of L. monocytogenes in most samples remained below 10 CFU/g, the food safety criterion (100 CFU/g) was exceeded in certain fish, meat, and fruit and vegetable products. The findings demonstrated that plant powders, especially rhubarb, inhibited the growth of microorganisms, with the exception of L. monocytogenes. The most effective suppression of microbial growth was achieved using mixtures of plant powders, particularly in low-fat minced meat samples. The utilisation of juice processing by-products, such as pomaces, offers a promising approach to improving the microbiological quality of meat products while aligning with the principles of the circular bioeconomy. | eng |
| dc.description.abstract | LÜHIKOKKUVÕTE. Listeria monocytogenes on toiduga leviv patogeen, mis kujutab rahvatervise riski, eelkõige pika säilimisajaga kuumtöötlemist mittevajavate valmistoitude tarbimisel. Patogeeni võime püsida eluvõimelisena ja paljuneda külmkapitemperatuuril on eriti ohtlik riskirühmadesse kuuluvate tarbijate jaoks. Tarbijate huvi looduslike ja minimaalselt töödeldud toitude vastu tingib vajaduse leida alternatiive sünteetilistele säilitusainetele. Väitekirjas hinnati L. monocytogenes’e esinemist Eestis toodetud valmistoitudes ning analüüsiti taimsete pulbrite ja nende segude mõju mikroobide paljunemisele tooretes ja kuumtöödeldud hakklihaproovides. Uurimuse tulemused näitasid, et valmistoitude saastumine L. monocytogenes’ega oli üldiselt väike, s.o 3,6% proovidest (n = 30 016). Enim esines patogeen kalatoodetes, eriti kergelt soolatud ja külmsuitsutatud kalas. Kuigi enamikes proovides jäi L. monocytogenes’e arv < 10 PMÜ/g, ületas see teatud kala-, liha- ning puu- ja köögiviljatoodete puhul toiduohutuskriteeriumi (100 PMÜ/g). Selgus, et taimsed materjalid, eeskätt rabarberivarrepulber, pärssisid mikroobide, v.a L. monocytogenes’e paljunemist. Kõige tõhusam mikroobide kasvu pärssimine saavutati taimsete pulbrite segudega, eriti väikese rasvasisaldusega hakklihaproovides. Lihatoodete mikrobioloogilise kvaliteedi parandamiseks on võimalik kasutada mahlatööstuse pressjääke, mis on ka kooskõlas ringbiomajanduse põhimõtetega. | est |
| dc.identifier.citation | Koskar, J. (2026). Listeria monocytogenes in ready-to-eat food and antimicrobial effect of plant additives in meat products [Estonian University of Life Sciences]. https://doi.org/10.15159/EMU.176 | eng |
| dc.identifier.isbn | 978-9916-91-067-2 (print) | |
| dc.identifier.isbn | 978-9916-91-068-9 (pdf) | |
| dc.identifier.issn | 2382-7076 | |
| dc.identifier.uri | http://hdl.handle.net/10492/11008 | |
| dc.identifier.uri | https://doi.org/10.15159/emu.176 | |
| dc.publisher | Estonian University of Life Sciences | eng |
| dc.relation.ispartofseries | Doctoral Theses of the Estonian University of Life Sciences | eng |
| dc.relation.ispartofseries | Eesti Maaülikooli doktoritööd | est |
| dc.rights | info:eu-repo/semantics/openAccess | eng |
| dc.rights.holder | © Julia Koskar, 2026 | |
| dc.rights.uri | https://www.riigiteataja.ee/en/eli/ee/Riigikogu/act/519062017005/consolide | est |
| dc.subject | Listeria monocytogenes | lat |
| dc.subject | RTE food | eng |
| dc.subject | plant additives | eng |
| dc.subject | dissertations | eng |
| dc.subject | Green University (thesis is related to EMÜ Green University iniciative’s aims) | eng |
| dc.title | Listeria monocytogenes in ready-to-eat food and antimicrobial effect of plant additives in meat products | eng |
| dc.title.alternative | Listeria monocytogenes valmistoidus ning taimsete lisandite antimikroobne toime lihatoodetes | eng |
| dc.type | Doctoral Thesis | eng |
| dc.type.qualificationname | PhD | eng |
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