Micro December 2018

( d ) The counting range for E. coli on the 3M Petrifilm Rapid E. coli /Coliform Count Plate is 1 lower than or equal to 100 blue to blue-green colonies with and without gas regardless of the 2

number of total colonies. The counting range for total coliforms on 3M Petrifilm Rapid E. 3

coli /Coliform Count Plate is lower than or equal to 100 colonies. The countable range for E. coli 4

or total coliform may occur on separate dilutions. 5 ( e ) 3M Petrifilm Rapid E. coli /Coliform Count Plates with colony counts too numerous to 6 count (TNTC) may have one or more of the following characteristics: lightening of the gel color 7

to yellow, many small, indistinct red or blue colonies and/or many gas bubbles. High 8

concentrations of E. coli or coliforms may cause the outer edge of the growth area to turn pink 9

to pink orange. When this occurs, record results as TNTC. For a more accurate count, further 10

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dilution of the sample may be necessary.

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( f ) If the 3M Petrifilm Rapid E. coli /Coliform Count Plates cannot be counted within the

incubation period, they may be stored for later enumeration by freezing in a sealable container 13

at temperatures lower than or equal to negative 15°C (5°F) for no longer than one week. 14 ( g ) For further information refer to the “3M™ Petrifilm™ Rapid E. coli /Coliform Count 15 Plate Interpretation Guide”. If you have questions about specific applications or procedures, 16

please visit our website at www.3M.com/foodsafety or contact your local 3M representative or 17

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distributor.

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Confirmation

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