Storage And Disposal - 3M Petrifilm Instrucciones De Uso

The user must train its personnel in proper testing techniques. Follow Good Laboratory Practices (U.S. Food and
Drug Administration, Title 21, Part 58 of the Code of Federal Regulation) or ISO 7218.
DISCLAIMER OF WARRANTIES / LIMITED REMEDY
UNLESS OTHERWISE PROHIBITED BY LAW, 3M DISCLAIMS ALL EXPRESS AND IMPLIED WARRANTIES, INCLUDING,
BUT NOT LIMITED TO, ANY WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. If any 3M
Petrifi lm Plate is proven to be defective, 3M or its authorized distributor will replace or, at its option, refund the
purchase price of any plate. These are your exclusive remedies. You must promptly notify 3M within sixty days
of discovery of any suspected defect in a product and return the product to 3M. Please call Customer Service
(1-800-328-1671 in the U.S.) or your offi cial 3M Microbiology representative for a Returned Goods Authorization.
LIMITATION OF 3M LIABILITY
UNLESS OTHERWISE PROHIBITED BY LAW, 3M WILL NOT BE LIABLE TO USER OR OTHERS FOR ANY LOSS OR
DAMAGE, WHETHER DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, INCLUDING, BUT
NOT LIMITED TO, LOST PROFITS. Except where prohibited by law, in no event shall 3M's liability under any legal
theory exceed the purchase price of the plates alleged to be defective. Customer may have additional rights and
should seek advice in country of purchase.

STORAGE AND DISPOSAL

Store unopened Petrifi lm Plate pouches refrigerated or frozen at temperatures lower than or equal to 8ºC (46ºF).
Just prior to use, allow unopened pouches to come to room temperature before opening. Return unused plates
to pouch. Seal by folding the end of the pouch over and taping shut. To prevent exposure to moisture, do
not refrigerate opened pouches. Store resealed pouches in a cool dry place for no longer than one month. It
is recommended that resealed pouches of Petrifi lm Plates be stored in a freezer (see below) if the laboratory
temperature exceeds 25ºC (77ºF) and/or the laboratory is located in a region where the relative humidity
exceeds 50% (with the exception of air-conditioned premises).
To store opened pouches in a freezer, place Petrifi lm Plates in a sealable container. To remove frozen Petrifi lm
Plates for use, open the container, remove the plates that are needed and immediately return remaining plates to
the freezer in the sealed container. Plates should not be used past their expiration date. The freezer that is used
for open pouch storage must not have an automatic defrost cycle as this would repeatedly expose the plates to
moisture which can damage the plates.
Do not use plates that show discoloration. Expiration date and lot number are noted on each package of Petrifi lm
Plates. The lot number is also noted on individual plates.
After use, Petrifi lm AC Plates may contain microorganisms that may be a potential biohazard. Follow current
industry standards for disposal.
6
2
INSTRUCTIONS FOR USE
Sample Preparation
1. Use appropriate sterile diluents:
Butterfi elds phosphate buffer 1,2 , 0.1% peptone water
2,3
dipotassium hydrogen phosphate solution , saline solution (0.85-0.90%), bisulfi te-free letheen broth or
distilled water.
Do not use diluents containing citrate, bisulfi te or thiosulfate with Petrifi lm Plates; they can inhibit
growth. If citrate buffer is indicated in the standard procedure, substitute with one of the buffers listed
above, warmed to 40-45°C (104-107°F).
2. Blend or homogenize sample.
3. For optimal growth and recovery of microorganisms, adjust the pH of the sample suspension to 6.6 - 7.2.
For acidic products, adjust the pH with 1N NaOH. For alkaline products, adjust the pH with 1N HCl.
Plating
1. Place the Petrifi lm AC Plate on a fl at, level surface (see fi gure a).
2. Lift the top fi lm and with the pipette perpendicular dispense 1 mL of sample suspension onto the center of
bottom fi lm (see fi gure b).
3. Drop the top fi lm down onto the sample.(see fi gure c).
4. Place the plastic spreader with the recessed side down on the center of the plate (see fi gure d). Press
gently on the center of the spreader to distribute the sample evenly. Spread the inoculum over the entire
Petrifi lm Plate growth area before the gel is formed. Do not slide the spreader across the fi lm.
5. Remove the spreader and leave the plate undisturbed for at least one minute to permit the gel to form.
Incubation
Incubate plates in a horizontal position with the clear side up in stacks of no more than 20 plates. Several
incubation times and temperatures can be used depending on current local reference methods, some of which
are listed in the Specifi c Instructions for Validated Methods section.
Interpretation
1. Petrifi lm AC Plates can be counted using a standard colony counter or other illuminated magnifi er. Count all
red colonies regardless of size or intensity (see fi gure e).
2. The circular growth area is approximately 20 cm
than 300 colonies by counting the number of colonies in two or more representative squares and
determining the average number per square. Multiply the average number by 20 to determine the
estimated count per plate (see fi gure f).
1 , peptone salt diluent 2,3 , buffered peptone water
2 . Estimates can be made on plates containing greater
3
2,3 ,