Term
| Aerobic Plate Count (APC) and Most Probable Number (MPN) |
|
Definition
| measure only viable microorgs (live) |
|
|
Term
|
Definition
| measures both viable and non-viable microorgs |
|
|
Term
| APC used to assess prod quality by |
|
Definition
1. to monitor for compliance w/ standards
2. to monitor for compliance w/ purchase specifications
3. monitor adherence to GMPs |
|
|
Term
| APC does not measure actual # of bacteria because: |
|
Definition
1. cells do not separate from each other properly
2.bacteria can be viable but not non-culturable (VNC) - for many nonsporulating
3. injured microorgs and may not form colonies
3. |
|
|
Term
|
Definition
| Colony forming units per unit sample (APC method should not be reported as a total bacterial count) |
|
|
Term
| Sources of error in the APC method |
|
Definition
1. not all bacteria form visible colonies
2. clumping of cells
3. errors in dilution (inadequate shaking of sample) before pipetting
4. error in measuring quantities to be used to dilution
5. inaccurate counting of colonies
6. contamination of samples (not aseptic practice)
7. inhibitory substances left in glassware (not washing equipment properly)
8.failure to follow directions from manual |
|
|
Term
| Phosphate buffer or peptone water soln |
|
Definition
| a buffered isotonic soln that is usually used instead of sterile water for food |
|
|
Term
|
Definition
| 1ml/(9+1)mL = 1/10 = 10^-1 |
|
|
Term
|
Definition
| CFU/mL = (Total # colonies/vol on plate) x (1/dilution of tube) |
|
|
Term
|
Definition
-surface colony morphology is easily observed
-distinguish b/w 2 or more colony types
-diluted orgs are not subject to heat of agar |
|
|
Term
|
Definition
-1.APC 2.Yeast and Mold 3.E.coli/Coliform count plate
-contain indicator dyes that allow for
the easy enumeration of colonies
- 15 - 150 red dots |
|
|
Term
| Rules for Counting Colonies on Plates |
|
Definition
- APC: 25-250 colonies per plate
- >250 - TNTC
- <25 - EAPC (est. aerobic plate count) |
|
|
