Term
| Methods for enumeration of bacteria: |
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Definition
1. Microscopic counts
2. MPN (Most Probable Number)
3. SPC (Standard Plate Count)
4. Indirect methods |
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Term
| How do microscopic counts work? |
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Definition
- dilute
- microscope
-Petroff-Hauser chamber |
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Term
| What kind of samples can be counted by microscopic means with a geat deal of reliability and confidence? |
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Definition
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Term
| MPN: number of bacteria determined by the relationship of... to ... |
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Definition
relationship of growth parameter to statistical probability
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Term
| The MPN method is limited to ... |
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Definition
| ... testing where statistical tables have been set up for a particular growth parameter. |
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Term
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Definition
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Term
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Definition
- dilutions
- plating onto media
- # colonies counted |
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Term
| The # bacteria in the original sample is det in SPC by ... |
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Definition
... multiplying the
#colonies by the dilution factor. |
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Term
| Counts by the SPC method are reported as ... |
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Definition
... CFUs
(colony forming units) |
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Term
| Only numbers between ... CFUs are considered statistically valid. |
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Definition
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Term
| What kind of cells does the SPC method determine? |
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Definition
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Term
| What kind of cells does a microscopic count determine? |
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Definition
| Both living and dead cells. |
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Term
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Definition
Yes!
because specific conditions and media used may exclude certain bacteria in the counts. |
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Term
| Turbidity occurs as cells ... |
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Definition
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Term
| Cell turbidity is measured in a ... |
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Definition
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Term
| A spectrophotometer measures... |
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Definition
... the absorbance of a culture
(OPTICAL DENSITY) |
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Term
| What kind of cell does turbidity (indirect method) determine? |
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Definition
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Term
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Definition
A = log (1/T)
T = transmitted light
%T =(I/I0)x 100
I = intensity of light after passing through the sample
I0 = intensity of light striking the sample |
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Term
| The amount of light absorbed is proportional to ... |
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Definition
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