Species-specific quantification of probiotic lactobacilli in yoghurt by quantitative real-time PCR
Article first published online: 10 OCT 2013
© 2013 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 115, Issue 6, pages 1402–1410, December 2013
How to Cite
Herbel, S.R., Lauzat, B., von Nickisch-Rosenegk, M., Kuhn, M., Murugaiyan, J., Wieler, L.H. and Guenther, S. (2013), Species-specific quantification of probiotic lactobacilli in yoghurt by quantitative real-time PCR. Journal of Applied Microbiology, 115: 1402–1410. doi: 10.1111/jam.12341
- Issue published online: 15 NOV 2013
- Article first published online: 10 OCT 2013
- Accepted manuscript online: 12 SEP 2013 01:17AM EST
- Manuscript Accepted: 4 SEP 2013
- Manuscript Revised: 19 AUG 2013
- Manuscript Received: 3 JUN 2013
- ZIM fond (Zentrales Innovationsprogramm Mittelstand). Grant Number: KF2267401MD9
- Federal Ministry of Economics and Technology of the Federal Republic of Germany
- IBMT Fraunhofer Institute
- CONGEN Biotechnologie GmbH. Grant Number: SFB852/1
- fermented foods;
- lactic acid bacteria;
- Lactobacillus ;
Lactobacilli strains with probiotic effects have been widely used in dairy products such as yoghurts as well as in food additives and pharmaceuticals. Despite their successful commercial application, the current species identification and quantification methods of the genus Lactobacillus are time-consuming and labour-intensive.
Methods and Results
To fulfil the requirements of a robust quality management, we have developed a quantitative real-time PCR assay based on the heat shock protein 60 gene (hsp60) for accurate identification and quantification of five commercially important Lactobacillus species. The developed assay allows an unambiguous species-specific detection of the species Lact. acidophilus, Lact. brevis, Lact. delbrueckii subsp. bulgaricus, Lact. helveticus and Lact. reuteri from bacterial cultures as well as directly from dairy products for instance yoghurt.
With the assay, we were able to specifically detect lactobacilli strains down to 105 CFU ml−1 directly from yoghurt, which is a sufficient detection limit as commercial products usually contain 106–1012 CFU ml−1 of probiotic strains.
Significance and Impact of the Study
The real-time PCR assay developed here might become a convenient tool enabling an accurate, fast and sensitive detection of probiotic lactobacilli commercially used in food.