Või mikrobioloogilise kvaliteedi hindamine
Laen...
Kuupäev
2017
Kättesaadav alates
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Või mikrobioloogiline kvaliteet sõltub mitmetest teguritest – tooraine kvaliteedist,
töötlemisviisidest, kasutatud lisanditest, aga ka pakendamisest. Lisandite lisamisega
parandatakse toote maitsekvaliteeti, kuid nende lisamisel võib tootesse sattuda soovimatuid
mikroorganisme. Vaatamata või kõrgele rasvasisaldusele ning kvaliteetsele tootmisele ja
sellest tulenevalt pikale säilivusajale, võib ristsaastumise tulemusel toote kvaliteet aga
märgatavalt langeda ning säilivusaeg lüheneda.
Antud magistritöö eesmärk oli hinnata mikroobide, sh. hallitus- ja pärmseente, esinemist
erinevat tüüpi võides. Selgitada, kuidas mõjutab või plasmafaasi eraldamine võirasvast
mikroobide üldarvu hindamist ning tuvastada, kuidas mõjutavad maitselisandid
(soolakristallid, karulauk ja päikesekuivatatud tomat) mikroobide üldarvu võis.
Uurimustööks vajalik materjal, proovid traditsioonilisest ja lisanditega võist, koguti
koostöös kahe erineva Eestis tegutseva piimatööstusettevõttega perioodil september 2016
kuni märts 2017. Kokku koguti võiproove 37. võipartiist ja viiest maitselisandi partiist.
Töös kasutati mikroobide üldarvu hindamisel nelja erinevat meetodit või plasmafaasi
eraldamiseks rasvafaasist. Kasutatud meetodite puhul leiti mikroobide üldarvus mitmeid
erinevusi, mis tulenevad või plasma- ja rasvafaasi segunemisest proovivõtul. Mida enam
sisaldas võiproov rasvafaasi, seda väiksem oli mikroobide üldarv. Mikroobide üldarv sama
tööstuse traditsioonilises ja soolakristallidega võis oli sarnane (p>0,05), jäädes vahemikku
2,05 – 2,65 log PMÜ/ml, samas kui päikesekuivatatud tomati- ja karulaugulisandiga võis
oli see eelmistega võrreldes oluliselt kõrgem (2,89 - 3,55 log PMÜ/ml, p<0,05). Hallitus- ja pärmseente kasvu tuvastati vaid 6 võipartiis. Kõige enam leidus hallitus- ja
pärmseeni taimsete maitselisanditega ehk päikesekuivatatud tomati- ja karulaugulisandiga
võis.
Magistritöö raames identifitseeriti MALDI-TOF analüüsil võiproovidest isoleeritud
mikroobe. Kõige suurem liigiline varieeruvus (14 liiki) leiti päikesekuivatatud tomatiga
võis, kus enim esindajaid kuulusid perekondadesse Bacillus, Lactobacillus ja
Staphylococcus.
Kokkuvõtteks võib öelda, et või mikrobioloogiline kvaliteet Eestis on väga hea, kuid
tugevamate seoste leidmiseks mikrobioloogilise kvaliteedi hindamismeetodite ja erinevate
võitüüpi vahel peaks uuritavat valimit oluliselt suurendama.
Microbiological quality of butter depends on many factors such as quality of raw material, processing methods, used aditives but also packaging process. Flavor additives are used to improve the product quality, but they might also contaminate the product with microbes. Despite the high level of fat and quality of production and long storage time coming from that, the result of crosscontamination may degrade the quality of the product and decrease its storage time. Aim of this study was to evaluate the presence of microbes in various types of butter. To explain how reducing fat in serumphase in butter samples may influence the evaluation of the total number of microbes and to identify how saltcrystals and herbs (ramsons and sundryed tomato) influence the total number of microbes in butter. Materials, samples from traditional butter and butter with salt or herb additives, were collected in co-operation with two Estonian dairy companies during September 2016 to March 2017. In total there were collected samples from 37 batches of butter and five batches of additives used in tested butter. Four distinct methods to separate serum phase from the fat phase were used in this work. A strong negative correlation between the total count of microbes and fat content in samples was found. The higher was the fat content in sample, the lower was the count of microbes.The amount of microbes in traditional and salt crystals containing butter is similar (p>0.05), ranging from 2.05 – 2.65 log CFU/ml, while in butter with sundried tomato or ramsons the level is significantly higher compared to previous (2.89 – 3.55 log CFU/ml, p˂0.05). Molds and yeasts were present in only six butter batches. Most of the molds and yeasts were found in buttersamples containing herbs. In the context of the research MALDI-TOF analysis was conducted to identify microbes isolated from the buttersamples. The biggest variation in species (14 species) was found in buttersamples containing sundryed tomatoes – mostly species from genus Bacillus, Lactobacillus and Staphylococcus. In conclusion, it is possible to say that the microbial quality of the butter produced in Estonia is very good. To assess a stronger connection between the evaluation methods of microbiological quality and different types of butter, the tested sample size must be significantly higher, covering different seasons due to fluctuations in raw milk, influencing microbiota in the butter.
Microbiological quality of butter depends on many factors such as quality of raw material, processing methods, used aditives but also packaging process. Flavor additives are used to improve the product quality, but they might also contaminate the product with microbes. Despite the high level of fat and quality of production and long storage time coming from that, the result of crosscontamination may degrade the quality of the product and decrease its storage time. Aim of this study was to evaluate the presence of microbes in various types of butter. To explain how reducing fat in serumphase in butter samples may influence the evaluation of the total number of microbes and to identify how saltcrystals and herbs (ramsons and sundryed tomato) influence the total number of microbes in butter. Materials, samples from traditional butter and butter with salt or herb additives, were collected in co-operation with two Estonian dairy companies during September 2016 to March 2017. In total there were collected samples from 37 batches of butter and five batches of additives used in tested butter. Four distinct methods to separate serum phase from the fat phase were used in this work. A strong negative correlation between the total count of microbes and fat content in samples was found. The higher was the fat content in sample, the lower was the count of microbes.The amount of microbes in traditional and salt crystals containing butter is similar (p>0.05), ranging from 2.05 – 2.65 log CFU/ml, while in butter with sundried tomato or ramsons the level is significantly higher compared to previous (2.89 – 3.55 log CFU/ml, p˂0.05). Molds and yeasts were present in only six butter batches. Most of the molds and yeasts were found in buttersamples containing herbs. In the context of the research MALDI-TOF analysis was conducted to identify microbes isolated from the buttersamples. The biggest variation in species (14 species) was found in buttersamples containing sundryed tomatoes – mostly species from genus Bacillus, Lactobacillus and Staphylococcus. In conclusion, it is possible to say that the microbial quality of the butter produced in Estonia is very good. To assess a stronger connection between the evaluation methods of microbiological quality and different types of butter, the tested sample size must be significantly higher, covering different seasons due to fluctuations in raw milk, influencing microbiota in the butter.
Kirjeldus
Magistritöö
Liha- ja piimatehnoloogia õppekaval
Märksõnad
magistritööd, metoodikad, või, maitselisandid, mikroobid