Microbiologia
Páginas: 3 (703 palabras)
Publicado: 23 de junio de 2011
3Petrifilm Plate
Guide to Dilution Preparation
Many foods require a dilution step before plating. The following is a guide to follow when preparing dilutions. Please refer to the 3M™ Petrifilm™plate application sheet Use with Dairy and Juice Products for specific dilution recommendations.
D I L U T I O N S A M P L E S I Z E D I L U E N T
10.00g
40
mL
1:5 1:10 1:20
Diluent VolumeCalculations:
or
22.50g
or
90
mL
24.75g
99 9
mL
mL
1.00g
or
10.00g
or
90
mL
11.00g
99 90
mL
mL
4.74g
or
5.21g
99
mL
Volume of Buffer Needed =(Weight of Sample x Dilution) – Weight of Sample Example: You have 7.5mL of sample and want to prepare 1:10 dilution.
(
7.5mL
Weight of Sample
x
10
Dilution
)
–
7.5mL
Weightof Sample
=
67.5mL
Volume of Buffer Needed
For detailed WARNING, CAUTIONS, DISCLAIMER OF WARRANTIES / LIMITED REMEDY, LIMITATION OF 3M LIABILITY, STORAGE AND DISPOSAL information, andINSTRUCTIONS FOR USE see Product’s package insert.
Making Dilutions with 3M™ Electronic Pipettors:
Refer to table on front page for alternate dilution preparations.
Note: Finished milk can be tested byplating 1mL of undiluted sample directly to a Petrifilm plate.
11g + 99mL Sterile = 1:10 Dilution
Sterile Diluent
1:10 Dilution
Sterile Diluent
Sterile Diluent
1:10 Dilution
Sample1
For 1:10 Dilution Use 3M Electronic Pipettor to mix 11g of sample into 99mL of sterile diluent.
1mL
3
For 1:100 Dilution Change tip of pipettor, draw up 0.9mL of sterile diluent.
5For 1:1000 Dilution Draw up 1mL of the 1:10 diluted sample and add 99mL of sterile diluent.
1mL + 99mL Sterile = 1:1000 Dilution
1mL
1mL
2
Dispense 1mL of 1:10 dilution to Petrifilmplate.
4
In addition, draw up 0.1mL of the 1:10 diluted sample and dispense full 1mL to Petrifilm plate.
1:100
Dilution
6
Change tip, draw up 1mL of the 1:1000 dilution and dispense to...
Guide to Dilution Preparation
Many foods require a dilution step before plating. The following is a guide to follow when preparing dilutions. Please refer to the 3M™ Petrifilm™plate application sheet Use with Dairy and Juice Products for specific dilution recommendations.
D I L U T I O N S A M P L E S I Z E D I L U E N T
10.00g
40
mL
1:5 1:10 1:20
Diluent VolumeCalculations:
or
22.50g
or
90
mL
24.75g
99 9
mL
mL
1.00g
or
10.00g
or
90
mL
11.00g
99 90
mL
mL
4.74g
or
5.21g
99
mL
Volume of Buffer Needed =(Weight of Sample x Dilution) – Weight of Sample Example: You have 7.5mL of sample and want to prepare 1:10 dilution.
(
7.5mL
Weight of Sample
x
10
Dilution
)
–
7.5mL
Weightof Sample
=
67.5mL
Volume of Buffer Needed
For detailed WARNING, CAUTIONS, DISCLAIMER OF WARRANTIES / LIMITED REMEDY, LIMITATION OF 3M LIABILITY, STORAGE AND DISPOSAL information, andINSTRUCTIONS FOR USE see Product’s package insert.
Making Dilutions with 3M™ Electronic Pipettors:
Refer to table on front page for alternate dilution preparations.
Note: Finished milk can be tested byplating 1mL of undiluted sample directly to a Petrifilm plate.
11g + 99mL Sterile = 1:10 Dilution
Sterile Diluent
1:10 Dilution
Sterile Diluent
Sterile Diluent
1:10 Dilution
Sample1
For 1:10 Dilution Use 3M Electronic Pipettor to mix 11g of sample into 99mL of sterile diluent.
1mL
3
For 1:100 Dilution Change tip of pipettor, draw up 0.9mL of sterile diluent.
5For 1:1000 Dilution Draw up 1mL of the 1:10 diluted sample and add 99mL of sterile diluent.
1mL + 99mL Sterile = 1:1000 Dilution
1mL
1mL
2
Dispense 1mL of 1:10 dilution to Petrifilmplate.
4
In addition, draw up 0.1mL of the 1:10 diluted sample and dispense full 1mL to Petrifilm plate.
1:100
Dilution
6
Change tip, draw up 1mL of the 1:1000 dilution and dispense to...
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