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Enumeration of yeast and mold in tea and herbs using different methods and culture media

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dc.contributor.author Jayashantha, E.T.
dc.contributor.author Asalaarachchi, G.
dc.contributor.author Abeygunawardena, S.I.
dc.date.accessioned 2017-01-06T05:42:51Z
dc.date.available 2017-01-06T05:42:51Z
dc.date.issued 2016
dc.identifier.citation Jayashantha, E.T., Asalaarachchi, G. and Abeygunawardena, S.I. 2016. Enumeration of yeast and mold in tea and herbs using different methods and culture media. In Proceedings of the International Research Symposium on Pure and Applied Sciences (IRSPAS 2016), Faculty of Science, University of Kelaniya, Sri Lanka. p 119. en_US
dc.identifier.isbn 978-955-704-008-0
dc.identifier.uri http://repository.kln.ac.lk/handle/123456789/15774
dc.description.abstract The International Standard Organization (ISO) has recommended the use of Dichloran 18% glycerol agar (DG-18) to enumerate yeast and mold in food (ISO 21527-2:2008) with reduced water activity (aw < 0.95). This ISO method uses the Surface Spread technique (SS-t). According to the ISO standard procedure, pour plate method is allowed to perform after a proper validation of results using the same medium. The objective of this study was to compare the Pour Plate technique (PPt) and spread plate technique using DG18 agar medium to enumerate yeast & mold in tea and herbs (e.g. lemongrass). The DG 18 agar medium was also compared with Yeast extract Dextrose Chloramphenicol (YDC) agar to enumerate these microorganisms. The tea samples and the herbs obtained from tea industry were used as the matrices for this study because these components have a water activity a less than <0.95. The sample preparation and the test were performed according to the ISO 21527-2:2008 standard procedures. Total of 20 samples of herbs and tea were used in this microbiological testing programme and the results were statistically analyzed using Paired-t test, with Minitab-14. The DG-18 medium gave average yeast and mold counts in tea samples as 2.58±0.42 CFU (log)/g in SS- technique whereas PP technique gave 0.41±0.08 CFU (log)/g. The fungal burden in herbs was 2.69 ±0.54 CFU (log)/g (SP-t) and 2.17 ±0.89 CFU (log)/g (PP-t). The YDC medium using pour plate technique gave average yeast and mold counts for tea and herb samples as 2.44 ±0.44 CFU (log)/g and 2.88 ±2 CFU (log)/g respectively. The DG-18 agar medium with the same technique gave 2.52±0.43 CFU (log)/g and 2.46±1.5 CFU (log)/g. The statistical analysis indicated that the results obtained either using two different media or using two different techniques with DG 18 medium were not significantly different. en_US
dc.language.iso en en_US
dc.publisher Faculty of Science, University of Kelaniya, Sri Lanka en_US
dc.subject Yeasts en_US
dc.subject Molds en_US
dc.subject Tea en_US
dc.subject DG-18 agar medium en_US
dc.title Enumeration of yeast and mold in tea and herbs using different methods and culture media en_US
dc.type Article en_US


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