Microbiological identification methods

Overall, microbiological assay methods have been the most sensitive of all assay systems and the ability to measure residues in the ppb to ppm range is common and has been for over 20 years (1 ). However, most of the residue assay systems lack specificity and require confirmation by spectral systems for a proper identification of the individual antibiotic or the antibiotic family. 

Identification Methods in Applied and Environmental Microbiology, ed. R.G. Board, D. Jones and F.A. Skinner, Society for Applied Bacteriology, Vol. 29, Blackwell, 1992. 

In the field of food microbiology, immunochemical methods are advantageous with respect to microbiological methods in terms of labor and time, in particular for those species and strains whose isolation and identification call for lengthy and cumbersome procedures. Immunochemical procedures allow cutting down substantially on these requirements, by following different strategies. 

Arias, C. R., Bums, J. K., Friedrich, L. M., Goodrich, R. M., Parish, M. E. (2002). Yeast species associated with orange juice evaluation of different identification methods. Applied and Environmental Microbiology, 68, 1955-1961. 

Water treatment by disinfection processes is considered a major public health achievement of the twentieth century. Consequently, there has been a shift in the identification methods of water contaminants from microbiological to chemical. The number of chemicals determined in drinking water has grown exponentially however, out of hundreds of them, only very few have been studied or have documented proof of their health effects. 

A. Saano and K. Lindstrom, Isolation and identification of DNA from soil. Methods in Applied Soil Microbiology and Biochemistry (K. Alef and P. Nannipieri, eds.). Academic Press, New York, 1995, p. 440. 

Microbiological methods are common in niacin determination, but they are time consuming and laborious. Instead, HPLC with RP column enables a better separation and identification of compounds. 

Chapin, K., and M. Musgnug. Evaluation of Three Rapid Methods for the Direct Identification of Staphylococcus aureus from Positive Blood Cultures. Journal of Clinical Microbiology 41 no. 9 (2003) 4324-4327. 

Recent interlaboratory comparisons of HPLC and microbiological methods for vitamin B6 revealed significant variability among laboratories (42,70). The extraction and hydrolysis of the B6 vitamers, especially the pyridoxine-/ -glucoside (PNG) in plant-based foods, were cited as problem areas. Other sources of analytical error included HPLC (mis)identification of the individual B6 vitamers, and vitamer interconversion during extraction and analysis. 

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