Pagaritööstuse biokirmes leiduvate sanitaarnäitlike mikroobide biotsiiditundlikkuse hindamine
Laen...
Kuupäev
2025
Kättesaadav alates
05.09.2025
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Biokirmete moodustumine toidutööstuse seadmetel ja pindadel kujutab endast tõsist hügieeniprobleemi, mis suurendab mikrobioloogilise saastumise ja toidu riknemise riski. Enamik senistest teadusuuringutest on keskendunud biokirmete struktuurile ning nende tekkemehhanismidele, samas kui mikroobikoosluste tundlikkust biotsiidide suhtes on vähem uuritud. Selle uurimissuuna põhjalikum käsitlemine on oluline tõhusate ja sihipäraste desinfitseerimisstrateegiate väljatöötamiseks, mis aitaksid ennetada biokile moodustumist ning vähendada saastumisriski toiduainetööstuses.
Magistritöö eesmärk oli määrata pagaritööstuse biokirme mikroobne kooslus ja hinnata sellest isoleeritud mikroobide tundlikkust kolme erineva biotsiidi suhtes. Uuritav materjal koosnes ühe Eesti pagaritööstuse hügieeni-, toote- ja tooraineproovidest, millest isoleeritud mikroobid identifitseeriti MALD-TOF MS abil. Valitud isolaatidest (n=42) kasvatati mikrotiiterplaadis biokirmed. Biokirme kvantitatiivseks määramiseks kasutati kristallvioletti ja metaboolse aktiivsuse hindamiseks 2,3,5-trifenüültetrasooliumkloriidi. Biokirme biomassi ning metaboolse aktiivsuse vähenemist määrati spektrofotomeetriliselt.
Töö tulemustest selgus, et pagaritööstuse biokirmes esinesid nii grampositiivsed kui ka gramnegatiivsed bakterid, sh domineerisid sugukondade Bacillaceae, Staphylococcaceae, Moraxellaceae ja Micrococcaceae liigid. Mikroobide biotsiiditundlikkus varieerus liikide ja tüvede lõikes. Kolmest uuritud biotsiidist põhjustas etanool biokirme massi vähenemist oluliselt nõrgemalt kui alus-hape ja P3Oxysan ZS, mille toime biokirme massi vähenemisele oli omavahel sarnane. Biokirmete metaboolset aktiivsust pärssis kõige tõhusamalt alus-happe kombinatsioon, olles oluliselt efektiivsem kui P3Oxysan ZS ja etanool, mille mõju metaboolsele aktiivsusele oli sarnane. Kokkuvõtteks, tulemused rõhutavad vajadusele kohandada sanitatsioonistrateegiaid ja arendada biotsiiditundlikkuse hindamiseks standardiseeritud meetodeid, mis võtaksid arvesse biokirmete spetsiifilisi omadusi ja käitumist.
Biofilm formation on equipment and surfaces within the food industry presents a significant hygienic challenge, increasing the risk of microbial contamination and food spoilage. While previous research has primarily focused on the structural characteristics and formation mechanisms of biofilms, the susceptibility of microbial communities within biofilms to biocides remains underexplored. A deeper understanding of this aspect is essential for developing effective and targeted disinfection strategies to prevent biofilm formation and reduce contamination risks in food processing environments. The objective of this master’s thesis was to characterize the microbial composition of biofilms in the bakery industry and to assess the sensitivity of isolated microorganisms to three different biocides. The study material consisted of hygiene, product, and raw material samples from an Estonian bakery. Microbial isolates were identified using MALDI-TOF mass spectrometry. Biofilms were cultivated in microtiter plates from selected isolates (n=42). Crystal violet staining was used to quantify biofilm biomass, while metabolic activity was assessed with 2,3,5-triphenyltetrazolium chloride assay. Reductions in biofilm biomass and metabolic activity were measured spectrophotometrically. The results demonstrated that bakery biofilms comprised both Gram-positive and Gram-negative bacteria, with dominant families including Bacillaceae, Staphylococcaceae, Moraxellaceae, and Micrococcaceae. Biocide sensitivity varied between species and strains. Among the tested biocides, ethanol caused a significantly weaker reduction in biofilm biomass compared to the acid-base combination and P3Oxysan ZS, which showed similar effects. The acid-base combination most effectively suppressed biofilm metabolic activity, being significantly more effective than both P3Oxysan ZS and ethanol, whose effects on metabolic activity were comparable. In conclusion, these findings highlight the importance of adapting sanitation strategies and developing standardized methods for assessing biocide susceptibility that consider the specific properties and behavior of biofilms.
Biofilm formation on equipment and surfaces within the food industry presents a significant hygienic challenge, increasing the risk of microbial contamination and food spoilage. While previous research has primarily focused on the structural characteristics and formation mechanisms of biofilms, the susceptibility of microbial communities within biofilms to biocides remains underexplored. A deeper understanding of this aspect is essential for developing effective and targeted disinfection strategies to prevent biofilm formation and reduce contamination risks in food processing environments. The objective of this master’s thesis was to characterize the microbial composition of biofilms in the bakery industry and to assess the sensitivity of isolated microorganisms to three different biocides. The study material consisted of hygiene, product, and raw material samples from an Estonian bakery. Microbial isolates were identified using MALDI-TOF mass spectrometry. Biofilms were cultivated in microtiter plates from selected isolates (n=42). Crystal violet staining was used to quantify biofilm biomass, while metabolic activity was assessed with 2,3,5-triphenyltetrazolium chloride assay. Reductions in biofilm biomass and metabolic activity were measured spectrophotometrically. The results demonstrated that bakery biofilms comprised both Gram-positive and Gram-negative bacteria, with dominant families including Bacillaceae, Staphylococcaceae, Moraxellaceae, and Micrococcaceae. Biocide sensitivity varied between species and strains. Among the tested biocides, ethanol caused a significantly weaker reduction in biofilm biomass compared to the acid-base combination and P3Oxysan ZS, which showed similar effects. The acid-base combination most effectively suppressed biofilm metabolic activity, being significantly more effective than both P3Oxysan ZS and ethanol, whose effects on metabolic activity were comparable. In conclusion, these findings highlight the importance of adapting sanitation strategies and developing standardized methods for assessing biocide susceptibility that consider the specific properties and behavior of biofilms.
Kirjeldus
Magistritöö
Toiduainete tehnoloogia õppekaval
Märksõnad
magistritööd, toiduohutus, toidukvaliteet, indikaatormikroorganismid, mikrotiiterplaat