Species identification in dairy products by three different DNA-based techniques

  • Annette Plath
  • Ingolf Krause
  • R. Einspanier
ORIGINAL PAPER

Abstract

 Polymerase chain reaction (PCR) with primers encoding a partial sequence of the β-casein gene was performed to detect the corresponding DNA in milk and cheese after an adapted DNA extraction procedure. In the PCR product from ovine or caprine β-casein DNA was shown to contain a specific restriction enzyme site that is not present in bovine β-casein DNA. Accordingly, after selected restriction enzyme analysis and horizontal polyacrylamide gel electrophoresis (PAGE), the undigested bovine β-casein fragment can be detected as an additional band if cow’s milk is present. Appropriate experiments using unprocessed milk demonstrated that a semi-quantitative assay could be established. The detection limit was about 0.5% cow’s milk in ewe’s and goat’s milk cheese. By use of a DNA intercalating agent the β-casein PCR products from cow or buffalo could be distinguished from those of ewe or goat as a consequence of sequence-specific retardation during agarose gel electrophoresis. Furthermore, single-stranded conformation polymorphism (SSCP) analysis was applied to detect expected species-specific conformation of the selected β-casein DNA sequences from the milk of cows, ewes, goats and buffalos milk. These techniques are compared with respect to their special use and application.

Key words DNA Polymerase chain reaction Single-stranded conformation polymorphism Restriction enzymes Cow’s ewe’s goat’s and buffalo’s cheese 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Annette Plath
    • 1
  • Ingolf Krause
    • 1
  • R. Einspanier
    • 1
  1. 1.Forschungszentrum für Milch und Lebensmittel, Technische Universität München, Vöttingerstrasse 45, D-85350 Freising, GermanyDE

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