1. Exercise 21: Enumeration Count colonies (30-300 plates) and share data
Lab 19 Goals and Objectives:
Exercise 21: Enumeration
Count colonies ( plates) and share data
(Sample data/explanations in supplemental packet pages 79-80)
Exercise 57: Bacterial Counts on Foods
Plate pre-made dilutions of foods
Use pre-poured solid plates and spread with beads
Each pair needs:
1:10 of each: meat, spinach, milk (no blending: done!)
1:1000 of each: meat, spinach, milk (no diluting: done!)
9 BHIA plates and 9 tubes of beads
Exercise 59: The Membrane Filter Method
Each pair use one clear environmental water sample
Perform according to directions pg 397 except skip step 4,
Filter 100ml of sample
Each pair needs: Filter apparatus, Grid filter disc, Absorbent pad,
Petri dish, Endo MF broth

2. 0.4
0.3
0.2
0.1
CFU/ml
2.55 X 105
3.4 X 106
y = mx+b
Once you can assign real CFU/ml numbers to the OD readings, you have a standard curve and the equation of the line can be used to determine the CFU/ml concentration in a sample from the OD reading

3. Fig 57.1
Dilutions already made, you just plate

4. From Introduction to Exercise 58
Coliform: gram-negative, facultative, non-endospore forming rods that ferment lactose to produce acid and gas
e.g. Intestinal Bacteria: Escherichia & Enterobacter
Used as indicators for
Vibrio cholerae: cholera
Salmonella typhi: typhoid fever
Shigella dysenteriae: bacillary dysentery

5. Fig 59.1

6. Exercise 21: Enumeration Count colonies (30-300 plates) and share data
Lab 19 Goals and Objectives:
Exercise 21: Enumeration
Count colonies ( plates) and share data
(Sample data/explanations in supplemental packet pages 79-80)
Exercise 57: Bacterial Counts on Foods
Plate pre-made dilutions of foods
Use pre-poured solid plates and spread with beads
Each pair needs:
1:10 of each: meat, spinach, milk (no blending: done!)
1:1000 of each: meat, spinach, milk (no diluting: done!)
9 BHIA plates and 9 tubes of beads
Exercise 59: The Membrane Filter Method
Each pair use one clear environmental water sample
Perform according to directions pg 397 except skip step 4,
Filter 100ml of sample
Each pair needs: Filter apparatus, Grid filter disc, Absorbent pad,
Petri dish, Endo MF broth