374 BACTERIOLOGICAL ANALYSES 
Total Solids Determination. 
(1) Use .3000 gram sample. Add 2 c.c. distilled water to 
the sample in this dish. Mix milk powder and water thoroughly 
with the blunt rod. 
(2) Continue the determination asunder evaporated milk. 
but continue heating in the vacuum oven for twenty minutes. 
CHAPTER XXXII. 
BACTERIOLOGICAL ANALYSES. 
While it is obviously beyond the scope and purpose of this 
volume to discuss in detail the technique of bacteriological 
analyses and microscopic preparations of the milk products de- 
scribed herein, it is deemed advisable to offer some suggestions 
that may serve for guidance of those who are not familiar with 
bacterial fermentations in condensed milk. 
Sampling.—Take samples of all products contained in open 
receptacles, such as fluid milk, plain condensed bulk milk, barreled 
sweetened condensed milk and milk powder, in sterile, cotton 
plugged test tubes, or in small sterile glass-stoppered bottles, 
and keep them in a cool place, preferably not above 35 degrees 
F. until ready to use. Keep canned condensed milk sealed in 
the original package until ready to use. Jf already open, invert 
a petri dish or a beaker over the can to avoid contamination 
from the air. 
Dilution for Numerical Counts.—Make dilutions in 250 c.c. 
class-stoppered flasks. Before opening sealed cans, thoroughly 
wipe off the entire top with a sterile piece of cheese cloth soaked 
in a saturated solution of mercuric bichloride or a 5 per cent 
solution of carbolic acid and flame the top of the can. Open 
evaporated milk cans by punching a hole into their top, large 
enough to insert the discharge end of a graduated pipette. Open 
sweetened condensed milk cans with a sterile knife or a sterile 
can opener. 
In the case of fluid milk and evaporated milk, measure with 
a sterile graduated pipette two cubic centimeters of the product 
and 198 cubic centimeters of sterile water into the 250 ¢.c. flask. 
Tn the case of plain condensed bulk milk, sweetened condensed 
