Identification of probiotic microorganisms in South African products using PCR-based DGGE analysis
Date
2005
Authors
Theunissen J.
Britz T.J.
Torriani S.
Witthuhn R.C.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Probiotic microorganisms in commercial yoghurts and other food products are currently identified by traditional methods such as growth on selective media, morphological and biochemical characteristics. In this study, PCR-based DGGE analysis was used for the rapid and accurate identification of probiotic microorganisms from South African yoghurts and lyophilized preparations in capsule and tablet form. To identify the microorganisms present in these products, the DGGE profiles obtained were compared to two reference markers (A and B) composed of five lactobacilli and seven Bifidobacterium species, respectively. The results obtained were confirmed by species-specific PCR, as well as sequence analyses of unknown bands not present in the reference markers. It was found that only 54.5% of the probiotic yoghurts contained the microorganisms stated on the label compared to only a third (33.3%) of the lyophilized probiotic products. Some Bifidobacterium species were incorrectly identified and various microorganisms were detected that were not listed on the label. Sequence analyses confirmed the presence of Streptococcus spp. other than the yoghurt starter, Streptococcus thermophilus, in some of these products and in some instances label information was vague and non-scientific. PCR-based DGGE analyses proved to be a valuable culture-independent approach for the rapid and specific identification of the microbial species present in South African probiotic products. © 2004 Elsevier B.V. All rights reserved.
Description
Keywords
probiotic agent, yoghurt, accuracy, analytic method, article, bacterial gene, bacterium detection, bacterium identification, Bifidobacterium, controlled study, denaturing gradient gel electrophoresis, food analysis, gene sequence, Lactobacillus, nonhuman, polymerase chain reaction, sequence analysis, South Africa, Streptococcus thermophilus, Bifidobacterium, Colony Count, Microbial, DNA, Bacterial, Electrophoresis, Agar Gel, Food Microbiology, Lactobacillus, Polymerase Chain Reaction, Probiotics, Sensitivity and Specificity, South Africa, Species Specificity, Yogurt, Bifidobacterium, Lactobacillus, Streptococcus, Streptococcus thermophilus
Citation
International Journal of Food Microbiology
98
1
98
1