Identification of the Bacterial Microflora in Dairy Products by Temporal Temperature Gradient Gel Electrophoresis

ABSTRACT Numerous microorganisms, including bacteria, yeasts, and molds, are present in cheeses, forming a complex ecosystem. Among these organisms, bacteria are responsible for most of the physicochemical and aromatic transformations that are intrinsic to the cheesemaking process. Identification of the bacteria that constitute the cheese ecosystem is essential for understanding their individual contributions to cheese production. We used temporal temperature gradient gel electrophoresis (TTGE) to identify different bacterial species present in several dairy products, including members of the genera Lactobacillus, Lactococcus, Leuconostoc, Enterococcus, Pediococcus, Streptococcus, and Staphylococcus. The TTGE technique is based on electrophoretic separation of 16S ribosomal DNA (rDNA) fragments by using a temperature gradient. It was optimized to reveal differences in the 16S rDNA V3 regions of bacteria with low-G+C-content genomes. Using multiple control strains, we first set up a species database in which each species (or group of species) was characterized by a specific TTGE fingerprint. TTGE was then applied to controlled dairy ecosystems with defined compositions, including liquid (starter), semisolid (home-made fermented milk), and solid (miniature cheese models) matrices. Finally, the potential of TTGE to describe the bacterial microflora of unknown ecosystems was tested with various commercial dairy products. Subspecies, species, or groups of species of lactic acid bacteria were distinguished in dairy samples. In conclusion, TTGE was shown to distinguish bacterial species in vitro, as well as in both liquid and solid dairy products.

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Analyzing RNA and DNA Folding Using Temperature Gradient Gel Electrophoresis (TGGE) with Application to In Vitro Selections

Methods in Enzymology - Biophysical, Chemical, and Functional Probes of RNA Structure, Interactions and Folding: Part A ◽

10.1016/s0076-6879(09)68018-6 ◽

2009 ◽

pp. 389-408 ◽

Cited By ~ 4

Author(s):

Durga M. Chadalavada ◽

Philip C. Bevilacqua

Keyword(s):

Temperature Gradient ◽

Gel Electrophoresis ◽

Dna Folding ◽

Gradient Gel Electrophoresis ◽

Temperature Gradient Gel Electrophoresis ◽

Rna And Dna

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Direct sequencing of variable HLA gene segments after in vitro amplification and allele separation by temperature-gradient gel electrophoresis

Journal of Immunological Methods ◽

10.1016/0022-1759(91)90113-t ◽

1991 ◽

Vol 142 (2) ◽

pp. 251-256 ◽

Cited By ~ 17

Author(s):

Christian G. Meyer ◽

Egbert Tannich ◽

Jutta Harders ◽

Karsten Henco ◽

Rolf D. Horstmann

Keyword(s):

Temperature Gradient ◽

Gel Electrophoresis ◽

Direct Sequencing ◽

Gradient Gel Electrophoresis ◽

Temperature Gradient Gel Electrophoresis

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Application of temperature gradient gel electrophoresis to the characterization of a nitrifying bioaugmentation product

FEMS Microbiology Ecology ◽

10.1111/j.1574-6941.2003.tb01068.x ◽

2003 ◽

Vol 43 (2) ◽

pp. 277-286 ◽

Cited By ~ 11

Author(s):

Melissa A. Fouratt ◽

Jeremy S. Rhodes ◽

Charles M. Smithers ◽

Nancy G. Love ◽

Ann M. Stevens

Keyword(s):

Temperature Gradient ◽

Gel Electrophoresis ◽

Gradient Gel Electrophoresis ◽

Temperature Gradient Gel Electrophoresis

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Influence of Camembert consumption on the composition and metabolism of intestinal microbiota: a study in human microbiota-associated rats

British Journal Of Nutrition ◽

10.1079/bjn20041192 ◽

2004 ◽

Vol 92 (3) ◽

pp. 429-438 ◽

Cited By ~ 18

Author(s):

Christophe Lay ◽

Malène Sutren ◽

Pascale Lepercq ◽

Catherine Juste ◽

Lionel Rigottier-Gois ◽

...

Keyword(s):

Intestinal Microbiota ◽

Dairy Products ◽

Basal Diet ◽

Fermented Milk ◽

Metabolic Characteristics ◽

Human Microbiota ◽

Gradient Gel Electrophoresis ◽

Metabolic Activities ◽

Temperature Gradient Gel Electrophoresis ◽

Micro Organisms

The objective of the present study was to evaluate the consequence of Camembert consumption on the composition and metabolism of human intestinal microbiota. Camembert cheese was compared with milk fermented by yoghurt starters andLactobacillus caseias a probiotic reference. The experimental model was the human microbiota-associated (HM) rat. HM rats were fed a basal diet (HMB group), a diet containing Camembert made from pasteurised milk (HMCp group) or a diet containing fermented milk (HMfm group). The level of micro-organisms from dairy products was measured in faeces using cultures on a specific medium and PCR–temporal temperature gradient gel electrophoresis. The metabolic characteristics of the caecal microbiota were also studied: SCFA, NH3, glycosidase and reductase activities, and bile acid degradations. The results showed that micro-organisms from cheese comprised 105–108bacteria/g faecal sample in the HMCp group.Lactobacillusspecies from fermented milk were detected in HMfm rats. Consumption of cheese and fermented milk led to similar changes in bacterial metabolism: a decrease in azoreductase activity and NH3concentration and an increase in mucolytic activities. However, specific changes were observed: in HMCp rats, the proportion of ursodeoxycholic resulting from chenodeoxycholic epimerisation was higher; in HMfm rats, α and β-galactosidases were higher than in other groups and both azoreductases and nitrate reductases were lower. The results show that, as for fermented milk, Camembert consumption did not greatly modify the microbiota profile or its major metabolic activities. Ingested micro-organisms were able to survive in part during intestinal transit. These dairy products exert a potentially beneficial influence on intestinal metabolism.

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