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Media for Detecting Pectolytic Gram‐Negative Bacteria Associated with the Softening of Cucumbers, Olives, and Other Plant Tissues a
Author(s) -
KING A. DOUGLAS,
VAUGHN REESE H.
Publication year - 1961
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1961.tb00809.x
Subject(s) - crystal violet , bacteria , agar , brilliant green , microbiology and biotechnology , biology , gram negative bacteria , erwinia , population , escherichia coli , chemistry , food science , biochemistry , genetics , organic chemistry , gene , demography , sociology
SUMMARY The limitations of cosine methylene blue or basic fuchsin polypectate gels prompted further investigations to develop a selective pectate gel that could be used to enumerate or isolate gram‐negative pectolytic bacteria even when they composed a minor portion of the microbial population. Crystal violet and brilliant green with bile proved the most effective of several selective agents studied. Of the two, crystal violet was much less inhibitory. Actidione, 10 mg per L added after sterilization, is helpful in the control of growth of molds and yeasts on this medium. The crystal violet medium has a productivity comparable to that of standard plate‐count agar when pure cultures are used. It was successfully used to enumerate known populations of pectolytic gram‐negative bacteria among mixed populations of other nonpectolytic gram‐negative and ‐positive bacteria. It is also being used routinely for enumeration and isolation of pectolytic gram‐negative bacteria from natural sources. Thus far, pectolytic bacteria belonging to 5 genera, including Aerobacter, Escherichia, Paracolobactrum, Aeromonas , and Achromobacter , have been isolated by use of the crystal violet gel.