Culture Media for Lactic Acid Bacteria

Abstract

This review deals with culture media for the detection, selective isolation and cultivation of different groups of lactic acid bacteria (LAB). Numerous elective and semi-selective media are available and currently used for LAB. Most of them have been developed to isolate certain groups of LAB from a specific habitat, such as meat or dairy products. These media can be rendered more selective by the addition of specific inhibitory agents or by reducing the pH. Members of the genera Lactobacillus, Leuconostoc, Pediococcus and Weissella (so-called LLPW group) share a number of physiological similarities and generally respond in the same way to conditions or compounds inhibitory to non-LAB. Therefore, most culture media developed for the detection of Lactobacillus or Leuconostoc are not completely selective for the respective genus. Carnobacteria can easily be distinguished from the LLPW group by their non-aciduric nature. However, because of physiological similarities to the genus Enterococcus, such as ability to grow at pH values up to 9.5, media developed for the selective isolation of Carnobacterium do not suppress growth of enterococci which often share the same habitat. Several useful selective media are available for beer pediococci, Tetragenococcus and Oenococcus, organisms characterised by specific properties associated with their adaptation to special environments. Because of the growing interest in probiotic strains and the inhabitants of the intestine, many media have been proposed in recent years for selective isolation of particular species or strains from those habitats, typically containing mixed populations of different LAB. Similarily, the increasing attention to safety aspects of LAB used as starter or probiotic cultures has emphasised the need for the development of a suitable medium for testing susceptibility to antibiotics.