Premium
Rapid Detection of Excessive CFU Counts of Enterobacteriaceae, S. aureus and Yeasts by Nitrate Reduction/Glucose Dissimilation (NGD) Monitoring in Selective Media
Author(s) -
NETTEN P.,
MOSSEL D. A. A.,
MOOSDIJK A.
Publication year - 1987
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.1365-2621.1987.tb06719.x
Subject(s) - nitrate , enterobacteriaceae , microbiology and biotechnology , chemistry , yeast , food science , chromatography , biology , biochemistry , escherichia coli , organic chemistry , gene
A technique was developed for the approximate selective estimation of CFU loads of thermotrophic Enterobacteriaceae and S. aureus in foods and meals, relying on rate of nitrate reduction and glucose dissimilation (NGD test) in lauryl sulfate nitrate glucose broth and modified liquid Baird Parker medium with nitrate and glucose added, respectively, both incubated at 42.5°C. Yeast CFU could be assessed similarly in oxytetracyclin gentamicin glucose broth at 30°C. The fate of nitrate and glucose was monitored by urinanalysis dip sticks. Response times were 7 and 2 hr for CFU levels of 10 5 and 10 8 g −1 , respectively, allowing feedback to production lines within one working day. The procedure requiring no other instrumentation than a centrifuge, also has been applied successfully as a field test procedure.