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Author Ilha, Eunice C. ♦ Scariot, Mirella C. ♦ Treml, Diana ♦ Pereira, Tomas P. ♦ Sant′Anna, Ernani S. ♦ Prudêncio, Elane S. ♦ Arisi, Ana C. M.
Source SpringerLink
Content type Text
Publisher Springer Berlin Heidelberg
File Format PDF
Copyright Year ©2015
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Life sciences; biology
Subject Keyword Lactobacillus paracasei ♦ Quantitative PCR ♦ Bacterial enumeration ♦ Yoghurt ♦ Tuf gene ♦ Microbiology ♦ Microbial Genetics and Genomics ♦ Microbial Ecology ♦ Mycology ♦ Medical Microbiology ♦ Applied Microbiology
Abstract Lactobacillus paracasei is a mesophilic lactic acid bacterium technologically active in food fermentation. Culture-independent methods have rapidly been recognized as a valuable alternative to culture-dependent methods for lactic acid bacteria enumeration. In the present work, the efficacy of different protocols to extract DNA from yoghurt were compared, real-time PCR (qPCR) targeting tuf gene for L. paracasei enumeration was evaluated, and qPCR and plate counts of L. paracasei in yoghurt samples were compared. Total DNA concentrations from commercial yoghurts were higher using DNAzol method 2 than using the other tested methods. Standard curves presented suitable mean efficiency values of 91 % (pure L. paracasei strain CTT 7501), 95 % (pure L. paracasei strain FNU), and 103 % (yoghurt with L. paracasei strain FNU). Limit of detection is 3 log DNA copy number, corresponding to 2.78 log CFU, a suitable range of CFU enumeration for probiotic bacteria in yoghurt samples, considering that they should be present in large amounts. The L. paracasei (CFU) enumerated by qPCR were compared to culturable L. paracasei enumerated by plate counts at 7, 14, 21, and 28 days of yoghurt manufacture. Differences between qPCR and plate counts were observed only 28 days after yoghurt preparation, counts were similar at 7, 14, and 21 days. In conclusion, this qPCR assay is a useful and rapid tool to enumerate L. paracasei in yoghurt, although it does not distinguish dead and viable cells.
ISSN 15904261
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2015-08-28
Publisher Place Berlin, Heidelberg
e-ISSN 18692044
Journal Annals of Microbiology
Volume Number 66
Issue Number 2
Page Count 10
Starting Page 597
Ending Page 606


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Source: SpringerLink