Abstract
A 24-h instrumental procedure is described for the quantitative estimation of coliforms in ground meat. The method is simple and rapid, and it requires but a single sample dilution and four replicates. The data are recorded automatically and can be used to estimate coliforms in the range of 100 to 10,000 organisms per g. The procedure is an impedance detection time (IDT) method using a new medium, tested against 131 stock cultures, that markedly enhances the impedance response of gram-negative organisms, and it is selective for coliforms. Seventy samples of ground beef were analyzed for coliforms by the IDT method and the conventional three-dilution, two-step most-probable-number test tube procedure. Seventy-nine percent of the impedimetric estimates fell within the 95% confidence limits of the most-probable-number values. This corresponds to the criteria used to evaluate other coliform tests, with the added advantage of a single dilution and more rapid results.
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Selected References
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- Cady P., Dufour S. W., Lawless P., Nunke B., Kraeger S. J. Impedimetric screening for bacteriuria. J Clin Microbiol. 1978 Mar;7(3):273–278. doi: 10.1128/jcm.7.3.273-278.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cady P., Dufour S. W., Shaw J., Kraeger S. J. Electrical impedance measurements: rapid method for detecting and monitoring microorganisms. J Clin Microbiol. 1978 Mar;7(3):265–272. doi: 10.1128/jcm.7.3.265-272.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Drion E. F., Mossel D. A. The reliability of the examination of foods, processed for safety, for enteric pathogens and Enterobacteriaceae: a mathematical and ecological study. J Hyg (Lond) 1977 Jun;78(3):301–324. doi: 10.1017/s0022172400056217. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Halvorson H. O., Ziegler N. R. Application of Statistics to Problems in Bacteriology: I. A Means of Determining Bacterial Population by the Dilution Method. J Bacteriol. 1933 Feb;25(2):101–121. doi: 10.1128/jb.25.2.101-121.1933. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hardy D., Kraeger S. J., Dufour S. W., Cady P. Rapid detection of microbial contamination in frozen vegetables by automated impedance measurements. Appl Environ Microbiol. 1977 Jul;34(1):14–17. doi: 10.1128/aem.34.1.14-17.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- JEFFRIES L. Novobiocin-tetrathionate broth: a medium of improved selectivity for the isolation of Salmonellae from faeces. J Clin Pathol. 1959 Nov;12:568–571. doi: 10.1136/jcp.12.6.568. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moats W. A. Comparison of four agar plating media with and without added novobiocin for isolation of salmonellae from beef and deboned poultry meat. Appl Environ Microbiol. 1978 Nov;36(5):747–751. doi: 10.1128/aem.36.5.747-751.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Restaino L., Grauman G. S., McCall W. A., Hill W. M. Effects of varying concentrations of novobiocin incorporated into two salmonella plating media on the recovery of four enterobacteriaceae. Appl Environ Microbiol. 1977 Mar;33(3):585–589. doi: 10.1128/aem.33.3.585-589.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- THOMAS H. A., Jr, WOODWARD R. L. Estimation of coliform density by the membrane filter and the fermentation tube methods. Am J Public Health Nations Health. 1955 Nov;45(11):1431–1437. doi: 10.2105/ajph.45.11.1431. [DOI] [PMC free article] [PubMed] [Google Scholar]