Lab 19 Goals and Objectives:

1
Lab 19 Goals and Objectives Exercise 22
Enumeration Count colonies (30-300 plates) and
share data (Sample data/explanations in
supplemental packet pages 69-72) Exercise 60
Bacterial Counts on Foods Plate pre-made
dilutions according to directions on pg 388 for
each of the following foods meat, spinach,
and milk Use pre-poured solid plates and spread
with beads Each pair needs 110 of each meat,
spinach, milk (no blending done!) 11000 of
each meat, spinach, milk (no diluting
done!) 9 NA plates and 9 tubes of
beads Exercise 61 Bacteriological Examination of
Water Pre-filter water with cheese-cloth in
funnel into new bottle Each pair set up tubes
for one water sample (you need minimum 200ml in
your sample for this exercise and Ex. 62) Each
pair needs 5 DS lactose broth LARGE tubes
10 SS lactose broth normal tubes Exercise
62 The Membrane Filter Method Each pair use the
same water sample from Exercise 61 Perform
according to directions pg 401 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
y mxb
3.4 X 106
2.55 X 105
CFU/ml
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 60.1
4
Figure 61.1
5
Lab 19 Goals and Objectives Exercise 22
Enumeration Count colonies (30-300 plates) and
share data (Sample data/explanations in
supplemental packet pages 69-72) Exercise 60
Bacterial Counts on Foods Plate pre-made
dilutions according to directions on pg 388 for
each of the following foods meat, spinach, and
milk Use pre-poured solid plates and spread with
beads Each pair needs 110 of each meat,
spinach, milk (no blending done!) 11000 of
each meat, spinach, milk (no diluting
done!) 9 NA plates and 9 tubes of
beads Exercise 61 Bacteriological Examination of
Water Pre-filter water with cheese-cloth in
funnel into new bottle Each pair set up tubes
for one water sample (you need minimum 200ml in
your sample for this exercise and Ex. 62) Each
pair needs 5 DS lactose broth LARGE tubes
10 SS lactose broth normal tubes Exercise
62 The Membrane Filter Method Each pair use the
same water sample from Exercise 61 Perform
according to directions pg 401 except skip step
4, Filter 100ml of sample Each pair needs
Filter apparatus, Grid filter disc, Absorbent
pad, Petri dish, Endo MF broth