Biokile mikrobioota leivatööstuse seadmetel
Laen...
Kuupäev
2020
Kättesaadav alates
05.09.2020
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Toiduga seotud bakterite poolt põhjustatud toiduainete riknemine on alati olnud suurteks
probleemiks toiduainete tööstuses. Toidu riknemine on sageli tingitud biokilest, mida
moodustavad bakterid toiduga kokkupuutuvatel pindadel, mistõttu seadmete puhtuse
jälgimine ning biokile tekkimise vältimine on toiduohutuse tagamiseks väga oluline.
Bakalaureusetöö eesmärk on anda ülevaade leivatööstuses juuretistega kokkupuutuvatel
seadmetel esinevate biokilede mikroobikoosluste kohta ning teostada mikrobioloogiline
ja molekulaarne uuring ühe Eestis tegutseva leivatööstuse seadmetelt kogutud
biokileproovidega.
Mikrobioloogilise uuringu käigus kirjeldati väljakasvanud mikroobide morfoloogiat,
isoleeriti ning säilitati mikroobide puhaskultuurid. Seejärel eraldati uuritavast materjalist
DNA ning teostati sellele PCR analüüs Staphylococcus aureus, Bacillus cereus, B.
subtilis ja Klebsiella pneumoniae tuvastamiseks.
Leiti, et 26% uuritavas materjalis esines B. cereus, B. subtilis ja K. pneumoniae. S.
aureus’e DNAd antud proovides ei tuvastatud. Samuti selgus, et ühes biokileproovis
võivad esineda mitmed patogeenide liigid korraga, mis tõenäoliselt muudab biokile
hävitamisele veelgi resistentsemaks ning millega suureneb leivajuuretise saastumise oht.
Kokkuvõtteks võib öelda, et leivatööstuse seadmetel esinevad potentsiaalselt patogeensed
bakterid on võimelised moodustama bakteriaalseid kooslusi ning püsima biokiles pika
perioodi jooksul. Töö raames isoleeritud mikroobide puhaskultuurid ning biokilest
eraldatud DNA säilitatakse edasisteks uuriguteks temperatuuril -80 °C.
Food spoilage caused by food‐related bacteria has always been a significant problem in the food industry. Food spoilage is often associated with biofilm formation on food contact surfaces, therefore monitoring the cleanliness of equpment and preventing the formation of biofilm is essential for food safety. The aim of this bachelor’s thesis was to provide an overview of the microbes that are present in biofilms on sourdough contact bakery equipments and also to conduct a microbiological and molecular study of biofilm samples collected from the industry equpments of one Estonian bakery. In the course of the microbiological study, the morphology of the microbes was described and pure microbial cultures were isolated and stored. DNA was then extracted from the biofilm samples in order to identify Staphylococcus aureus, Bacillus cereus, B. subtilis and Klebsiella pneumoniae in it by the PCR analysis. B. cereus, B. subtilis and K. pneumoniae were present in 26% of the studied samples. S. aureus DNA was not detected in these samples. Moreover, it was found that one biofilm sample could consist several species of pathogens, which is likely to make the biofilm even more resistant to destruction and increase the risk of contamination of sourdough. In conclusion, potentially pathogenic bacterial species, present on bakery equipments, are able to form bacterial communities and persist in the biofilm for a long period of time. During the research, microbial isolates and DNA extracted from the biofilm samples, were stored at -80 °C for futher studies.
Food spoilage caused by food‐related bacteria has always been a significant problem in the food industry. Food spoilage is often associated with biofilm formation on food contact surfaces, therefore monitoring the cleanliness of equpment and preventing the formation of biofilm is essential for food safety. The aim of this bachelor’s thesis was to provide an overview of the microbes that are present in biofilms on sourdough contact bakery equipments and also to conduct a microbiological and molecular study of biofilm samples collected from the industry equpments of one Estonian bakery. In the course of the microbiological study, the morphology of the microbes was described and pure microbial cultures were isolated and stored. DNA was then extracted from the biofilm samples in order to identify Staphylococcus aureus, Bacillus cereus, B. subtilis and Klebsiella pneumoniae in it by the PCR analysis. B. cereus, B. subtilis and K. pneumoniae were present in 26% of the studied samples. S. aureus DNA was not detected in these samples. Moreover, it was found that one biofilm sample could consist several species of pathogens, which is likely to make the biofilm even more resistant to destruction and increase the risk of contamination of sourdough. In conclusion, potentially pathogenic bacterial species, present on bakery equipments, are able to form bacterial communities and persist in the biofilm for a long period of time. During the research, microbial isolates and DNA extracted from the biofilm samples, were stored at -80 °C for futher studies.
Kirjeldus
Bakalaureusetöö
Toiduainete tehnoloogia õppekaval
Märksõnad
bakalaureusetööd, biokile, toiduohutus, patogeensed mikroobid, kvoorumtunnetus