M Petrifilm Coliform Count Plate 2 No growth = 0 Notice the changes in gel color in figures 2 through 5. As the coliform count increases, the gel colo

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1 Petrifilm Coliform Count Plate Interpretation Guide This guide familiarizes you with results on M Petrifilm Coliform Count plates. For more information, contact the official M Microbiology Products representative nearest you. Petrifilm Coliform Count (CC) plates contain Violet Red Bile (VRB) nutrients, a cold-water-soluble gelling agent, and a tetrazolium indicator that facilitates colony enumeration. The top film traps gas produced by the lactose fermenting coliforms. AOAC INTERNATIONAL and U.S. FDA Bacteriological Analytical Manual (BAM) define coliforms as gramnegative rods which produce acid and gas from lactose during metabolic fermentation. Coliform colonies growing on the Petrifilm CC plate produce acid which causes the ph indicator to deepen the gel color. Gas trapped around red coliform colonies indicates confirmed coliforms. The identification of coliforms may vary by country (see Reminders for Use section for incubation times and temperatures): AOAC INTERNATIONAL validated method Total coliform = 69 (colonies with gas)

M Petrifilm Coliform Count Plate 2 No growth = 0 Notice the changes in gel color in figures 2 through 5.

Background bubbles are a characteristic of the gel and are not a result of coliform growth.

Do not count colonies that appear on the foam barrier because they are removed from the selective influence of the medium. See circle.

Estimates can be made on plates containing greater than 50 colonies by counting the number of colonies in one or more representative

2 M Petrifilm Coliform Count Plate 2 No growth = 0 Notice the changes in gel color in figures 2 through 5. As the coliform count increases, the gel color deepens. Background bubbles are a characteristic of the gel and are not a result of coliform growth. Total coliform count = 79 The counting range for the total population on Petrifilm CC plates is Do not count colonies that appear on the foam barrier because they are removed from the selective influence of the medium. See circle. Estimated total coliform count = 220 The circular growth area is approximately 20 cm 2. Estimates can be made on plates containing greater than 50 colonies by counting the number of colonies in one or more representative squares and determining the average number per square. Multiply the average number by 20 to determine the estimated count per plate. Further dilution of the sample is recommended for an accurate count. 4 TNTC Petrifilm CC plates with colonies that are TNTC have one or more of the following characteristics: many small colonies, many gas bubbles, and a deepening of the gel color. 5

Actual count = 4 When high numbers of non-coliform organisms such as Pseudomonas are present on Petrifilm CC

6 Total coliform count = 2 Food particles are irregularly shaped and are not associated with gas bubbles.

Gas may disrupt the colony so that the colony outlines the bubble. See circles and 2.

3 Actual count = 4 When high numbers of non-coliform organisms such as Pseudomonas are present on Petrifilm CC plates, the gel may turn yellow. 6 Total coliform count = 2 Food particles are irregularly shaped and are not associated with gas bubbles Total coliform count = 8 Bubble patterns may vary. Gas may disrupt the colony so that the colony outlines the bubble. See circles and 2. Artifact bubbles may result from improper inoculation or from trapped air within the sample. They are irregularly shaped and are not associated with a colony. See circle. Examples 0 show various bubble patterns associated with gas producing colonies. All should be enumerated.

4 Petrifilm Coliform Count Plates Reminders for Use For detailed WARNING, CAUTIONS, DISCLAIMER OF WARRANTIES / LIMITED REMEDY, LIMITATION OF M LIABILITY, STORAGE AND DISPOSAL information, and INSTRUCTIONS FOR USE see Product s package insert. Storage Petrifilm Petrifilm Petrifilm Store unopened packages at 8 C To seal opened package, fold end 2 ( 46 F). Use before expiration date on over and tape shut. package. In areas of high humidity where condensate may be an issue, it is best to allow packages to reach room temperature before opening. Sample Preparation Do not refrigerate opened packages. Use Petrifilm plates within one month after opening Prepare a dilution of food product.* Weigh or pipette food product into an appropriate container such as a stomacher bag, dilution bottle, Whirl- Pak bag, or other sterile container. *See Petrifilm Use with Dairy and Juice Products sheet for recommended dilutions. Inoculation Add appropriate quantity of one of the following sterile diluents: Butterfield's phosphate buffer (IDF phosphate buffer, g/l of KH 2 PO 4 adjusted to ph 7.2), 0.% peptone water, peptone salt diluent (ISO method 6887), buffered peptone water (ISO method 6579), saline solution ( %), bisulfite-free letheen broth, or distilled water. Do not use buffers containing citrate, bisulfite, or thiosulfate; they can inhibit growth. Blend or homogenize sample per current procedure. Adjust ph of the diluted sample between 6.6 and 7.2 : for acid products, use N NaOH, for alkaline products, use N HCI. Place Petrifilm plate on level With pipette perpendicular to surface. Lift top film. Petrifilm plate, place ml of sample onto center of bottom film. Carefully roll top film down to avoid entrapping air bubbles. Do not let top film drop.

5 RIDGE side FLAT side With flat side down, place Gently apply pressure on spreader Lift spreader. Wait a minimum of 0 spreader on top film over inoculum. 2 to distribute inoculum over circular one minute for gel to solidify. area before gel is formed. Do not twist or slide the spreader. Incubation Interpretation <70 F Incubate plates in stacks of up to 20. Incubation time and temperature varies by method. Most common approved methods: Total coliforms AOAC Official Methods 986. and (milk, raw milk, other dairy products): Incubate 24h ± 2h at 2 C ± C. AOAC Official Method 99.4 (foods): Incubate 24h ± 2h at 5 C ± C. NMKL Method 47.99: Incubate 24h ± 2h at 7 C ± C. AFNOR validated methods M 0/2-09/89A and B (all food types except shellfish): Incubate 24h ± 2h at 0 C ± C. Thermotolerant (fecal) coliforms AFNOR validated method M 0/2-09/89C (all food types): Incubate 24h ± 2h at 44 C ± C. Incubator humidification is required at this elevated temperature. Petrifilm plates can be counted on a Colonies may be isolated for further 4 5 standard colony counter or other identification. Lift top film and pick illuminated magnifier. Refer to the the colony from the gel. Interpretation Guide section when reading results. Additional Comments Questions? U.S., call , Canada, call for technical service. To order Petrifilm plates in the U.S., call Latin America / Africa and Asia Pacific regions, call Microbiology Products M Center, Building 275-5W-05 St. Paul, MN USA microbiology@m.com M Canada, Inc. Post Office Box 5757 London, Ontario N6A 4T Canada M Europe Laboratoires M Santé Boulevard de l Oise F Cergy-Pontoise Cedex France Petrifilm is a trademark of M. Whirl-Pak is a registered trademark of Nasco. 40% Pre-consumer waste paper 0% Post-consumer waste paper Printed in U.S.A. M (29.2) DPI

6 Microbiology Products M Center, Building 275-5W-05 St. Paul, MN USA microbiology@m.com M Canada Inc. Post Office Box 5757 London, Ontario N6A 4T Canada M Europe Laboratoires M Santé Boulevard de l Oise F Cergy-Pontoise Cedex France % Pre-consumer waste paper 0% Post-consumer waste paper Printed in U.S.A. Copyright M (IPC)999. All rights reserved (29.2) DPI

3M Petrifilm E. coli/coliform Count Plate 2 3 No growth = 0 Notice the changes in gel color in figures 2 through 8. As the E. coli or coliform count i

3 Petrifilm E.coli/Coliform Count Plate Interpretation Guide This guide familiarizes you with results on 3M Petrifilm E. coli/coliform Count plates. For more information, contact the official 3M Microbiology