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General Microbiological Methods Information About BAM and CFSAN's Use of Microbiological Methods CFSAN Microbiological Methods Information BAM online:
Updates and Revisions Introduction Chapters 1. Food SamplingApril 2003 2. Microscopic Examination November 2000 4. Escherichia coli September 2002 4A. Escherichia coli September 2002 5. Salmonella April 2003, September 2005, December 2005, June 2006, and December 2007 6. Shigella October 2000 7. Campylobacter March 2001 8. Yersinia August 2007 9.Vibrio May 2004 10. Listeria monocytogenes January 2003 18. Yeasts, Molds and Mycotoxins April 2000 21A. Canned Foods November 2000 23. Microbiological Methods for Cosmetics August 2001 Appendices 1. Rapid MethodsJanuary 2001 2. Most Probable Number February 2006 Media M28a. Campylobacter enrichment broth (Bolton formula)December 2000 M29a. Abeyta-Hunt-Bark Agar December 2000 M30d. Semisolid Medium, modified, for Biochemical Identification March 2001 M52. Enrichment Broth, pH 7.3 ± 0.1 September 2000 M79. Letheen Broth (Modified) August 2001 M103. Motility Test Medium (Semisolid) September 2000 M152a. Trypticase Soy Agar-Magnesium sulfate-NaCl May 2004 M154b. Trypticase (Tryptic) Soy Broth with 1% NaCl and 24% glycerol May 2004 M156. Trypticase Soy Broth Modified January 2002 M188a. Universal Preenrichment Broth (without ferric ammonium citrate) December 2007 M189. Cellobiose-Colistin (CC) Agar May 2004 M190. Vibrio vulnificus Agar May 2004 M191. Vibrio parahaemolyticus sucrose Agar (VPSA) May 2004 M192. Buffered Peptone Water (BPW) September 2005 M193. Dey-Engley Broth December 2005 Reagents R90. Peptone-Tween-salt diluentMay 2004 R91. Sodium desoxycholate-0.5% in sterile dH2O (String test) May 2004 R92. (SDS) Sodium dodecyl sulfate-10% in sterile dH2O May 2004 R93. (SSC/SDS)Sodium dodecyl sulfate- May 2004 Advisories for BAM Users Cycloheximide Supply Update |
Microbiological Detection MethodsMethods development has always been driven by the demand for tests that are faster, cheaper, easier, and more accurate. Pressure for improved procedures is particularly apparent in microbial food safety, because traditional tests may involve many steps -- resuscitation of stressed microbial cells, enrichment of the few cells that may be present in a sample, selection that leads to the isolation of pure cultures, followed by identification, which could require a combination of morphological, biochemical, immunological and genetic techniques and, possibly, tests for virulence or toxicity using animal inoculation. Often, such test protocols take longer than the shelf life of the food being analyzed. Ways proposed to accelerate the procedure included, initially, improved media and compacted culturing. Then, automation began to replace manual execution. Also, indirect identification, i.e., by biochemical (e.g., fatty acid profiles, nucleic acid sequences) or biophysical shortcuts (FT-IR) that reveal organisms' pertinent biomarkers or genetic fingerprints, began to make the isolation of viable microbes not as necessary. These newer tests -- known as "rapid methods" if they took hours rather than days and as "real-time" testing if they took minutes -- have not yet, however, made traditional testing obsolete. There are good reasons why analysts should continue to have the traditional skills to resuscitate, enrich, isolate, and identify microorganisms. Often, some culturing is necessary before there is enough material for the application of a rapid method or real-time test. Then, too, foods may contain substances that interfere with biochemical/molecular test shortcuts. Furthermore, having a viable microbial isolate may still provide quantitative and infectivity information not otherwise available, or be mandatory because of regulatory requirements and legal issues, or be useful later for retrospective investigations such as the characterization of new biomarkers. And, since no two types of test have the same sensitivity, the old ones serve as convenient standards for false positive and false negative rates. Kit versions of rapid methods are interpreted differently depending on whether the results are positive or negative: negative results are considered definitive but positive results require confirmation by another test. The Bacteriological Analytical ManualFDA's Bacteriological Analytical Manual (The BAM) is a collection of procedures preferred by analysts in U.S. Food and Drug Administration laboratories for the detection in food and cosmetic products of pathogens (bacterial, viral, parasitic, plus yeast and mold) and of microbial toxins. The manual's contents reflect the history of methods development described above. Except for some rapid methods listed in Appendix 1, all these methods have been used and peer reviewed by FDA scientists as well as by scientists outside FDA. However, not all of these methods have been fully validated by collaborative studies. In some instances, collaborative studies are not possible because uniform test samples can not be prepared (as with encysted parasites). In other instances, FDA needs to use a method before the time it takes to achieve full validation. At first (1965, Edition 1), the BAM was intended to be only a vehicle for information and standardization within FDA. However, the manual's reputation as useful spread beyond the agency. Requests for copies proliferated and it was decided to make the BAM generally available. It has gone through 8 major editions, with, on occasion, revisions in between. Since 1976 (Edition 4), BAM has been published and distributed by AOAC International. In 1998, Edition 8, Revision A was issued not just as hard copy, but also in an electronic format (a CD-ROM version) by AOAC. Now, in 2000 AD, the BAM is being placed on the FDA/CFSAN internet site and is designated the BAM online. Continuous updating becomes possible, so editions as such will cease. Each section will bear the dates on which it was last reviewed and revised. AOAC will continue to publish a printed version on demand. Microbiological Methods Information on the CFSAN WebsiteAdvisory for BAM Users on Reported Supply Problems for Cycloheximide There have been reports of limited supplies of this reagent used in the BAM to prevent growth of yeasts and molds in some media Microbiological Methods Information on Selected WebsitesUSDA/FSIS Microbiological Laboratory Guidebook, 3rd Edition
Official Methods of Analysis of AOAC International |
Date of final revision: 2001-MAR-05. Composed by: RIM, GJJ, RB.