Microbiology Laboratory Guidebook, 3rd edition, 1998

The Guidebook contains current protocols for analytical tests required by FSIS regulatory activities on meat, poultry and egg products. Specifically, microbiological methods are presented for sample preparation, isolation and identification of the major foodborne pathogenic microorganisms and their toxins, meat tissue species identification, and the detection of extraneous materials and antimicrobial residues. Media and reagent formulations, and Most Probable Number Tables are contained in an appendix.

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Pen and Ink Changes

March 26, 2001: Requested Changes (# 1-2001 and # 2-2001) to the MLG, submitted by Mark D. Pratt and Cindy L. Reding on February 1, 2001, was reviewed and approved by the QC/QA Document Change Review Board effective March 26, 2001:

MLG 3rd edition, 1998, Chapter 4, Revision # 1; 1/10/01, Isolation and Identification of Salmonella From Meat, Poultry, and Egg Products, New Section 4.410, page 4-9 and Section 4.5 b., page 4-9.

ADD the following new Section on page 4-9.

4.410 Carcass Sponge Samples

1. Add 50 ml BPW to the sample bag containing the moistened sponge to bring the total volume to 60 ml. Mix well.
2. 
   
   
3. Incubate at 35 ± 1°C for 20-24 h.
4. 
   
   
5. Follow procedures in Section 4.45 d-i.

Section 4.5 b., page 4-9, change the first paragraph as follows:

b.

Pick up to three typical colonies from each plate, if available. ( NOTE: Before any sample is reported as Salmonella-negative, a total of three typical colonies, if available, from each selective agar plate must be examined). Pick only from the surface and center of the colony. Avoid touching the agar because these highly selective media suppress growth of many organisms that may be viable.

September 25, 2000: FSIS has also approved and issued the following changes to specific sections in other chapters of the 3rd Edition, 1998 Microbiology Laboratory Guidebook (MLG). These specific word changes to original referenced sections are as described below:

MLG 3rd edition, 1998, Chapter 34, Section 34.838 Confirmatory Identification of Tetracycline, page 34-41. Substitute the following paragraph:

To distinguish between the three tetracyclines, confirmatory identification can be achieved by thin layer chromatographic analysis outlined in Section 34.9 Identification of Tetracyclines in Tissue by Thin Layer Chromatography or by chemical confirmation using HPLC following FSIS chemical method ''Analysis of Tetracyclines in Beef, Pork, and Poultry Tissues.''

October 2, 2000: FSIS has also approved and issued the following changes to specific sections in other chapters of the 3rd Edition, 1998 Microbiology Laboratory Guidebook (MLG). These specific word changes to original referenced sections are as described below:

MLG 3rd edition, 1998, Chapter 34, Section 34.837 Tentative Identification of Tetracycline in Tissue from the Seven Plate Bioassay System, page 34-41. Add the following paragraph:

If the zone(s) of inhibition on the BC plate indicate(s) the concentration of tetracycline to be below the cutoff level for that species and tissue, then the test code 2298 (generic tetracycline) is assigned and the sample is considered a non-violation and the analyst does not proceed with further testing (confirmatory identification and quantitation). The cutoff level is the smallest BC zone size, specific for tissue and animal species, that will result in a calculated violative level for any of the three tetracyclines, minus two (2) millimeters. If the zones of inhibition indicate the presence of tetracycline at or above the cutoff level, then confirmatory identification and quantitation analysis is performed as outlined in Sections 34.838 and 34.839 respectively.

Printed Version

Due to various chapter revisions and pen and ink changes made to the original Microbiology Laboratory Guidebook publication, it is not completely up to date and is no longer available for commercial purchase.

The complete, current version of this document is available only from this web site.