Research Article Open Access

Formulation and Evaluation of a Selective Medium for Lactic Acid Bacteria-Validation on Some Dairy Products

Baida Djeghri-Hocine1, Messaouda Boukhemis1 and Abdeltif Amrane2
  • 1 Biochemistry and Applied Microbiology Laboratory, Department of Biochemistry, Faculty of Sciences, Badji-Mokhtar University, BP 12, 23000 Annaba, Algeria
  • 2 National School of Chemistry of Rennes, CNRS, UMR 6226, General Leclerc Avenue, CS 50837, 35708 Rennes Cedex 7, France

Abstract

Problem statement: Lactic Acid Bacteria (LAB) is characterized by fastidious nutritional requirements leading to the need for complex and rich media to allow growth. Owing to their complex requirements which also varied significantly with species, the formulation of selective media for LAB is difficult. Approach: A culture medium for LAB was previously developed based on deproteinated whey supplemented with yeast autolysate and de-lipidated egg yolk. Based on this previously developed medium, some selective media were formulated and their potential for LAB selection and enumeration was examined. Results: In this study, it was considered as a basis to define a selective medium, by adding a pH indicator and some inhibitory compounds to select the LAB flora of various dairy products including milk, disinfected or not, fermented milk and yoghurt. The addition of sodium azide to inhibit the contamination flora, including Gram negative floraand purple bromocresol allowed a direct selection of the Gram + and lactose + flora. An acidic pH (5.0) can also be helpfully considered after protein hydrolysis to avoid protein denaturation. Conclusion: To complete this study, additional work is needed concerning the improvement of culture medium selectivity by considering other inhibitors, of the Gram negative flora (like lithium chloride for instance), of fungi (like actidione), of the Gram positive flora (excepting the LAB flora) and an association of these inhibitors.

American Journal of Agricultural and Biological Sciences
Volume 5 No. 2, 2010, 148-153

DOI: https://doi.org/10.3844/ajabssp.2010.148.153

Submitted On: 28 February 2010 Published On: 30 June 2010

How to Cite: Djeghri-Hocine, B., Boukhemis, M. & Amrane, A. (2010). Formulation and Evaluation of a Selective Medium for Lactic Acid Bacteria-Validation on Some Dairy Products. American Journal of Agricultural and Biological Sciences, 5(2), 148-153. https://doi.org/10.3844/ajabssp.2010.148.153

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Keywords

  • Characterization
  • inhibitory compounds
  • lactic acid bacteria
  • selective media