10 
BULLETIN 563, U. S, DEPARTMENT OF AGRICULTURE, 
Table IV. — Variation in the bacterial content of samples of ice cream taken from gallon 
lots held in cold storage. 
Age of ice S ^" 
cream. ; {>£ 
Number of 
colonies on 
duplicate 
plates. 
Average Variation between 
count 1 lowest and highest 
per c. c. j counts. 
Fresh 
1 
2 
3 
4 
5 
6 
7 
8 
9 
64 
117 
120 
109 
95 
102 
138 
77 
131 
79 
""96" 
118 
118 
'"97" 
"i29* 
7,150 
11,700 
10,800 
10,350 
10,650 
10,200 
11,750 
7,700 
13,000 
Samples 1 and 9, 
81. 8i per cent. 
One month 
1 
2 
3 
4 
5 
6 
8 
9 
118 
106 
112 
111 
110 
104 
118 
102 
117 
"Hi' 
112 
""i06* 
11,800 
10,600 
11,200 
11,400 
11,100 
10,400 
11,800 
10,200 
11,150 
Samples 7 and 8, 
15.68 per cent. 
Two months 
1 
2 
3 
4 
5 
6 
7 
8 
9 
76 
66 
76 
92 
79 
73 
70 
75 
76 
77 
76 
76 
68 
82 
72 
80 
76 
92 
7,650 
7,100 
7,600 
8,000 
8,050 
7,250 
7,500 
7,500 
8,400 
Samples 2 and 9, 
18. 31 per cent. 
VARIATION IN SAMPLES TAKEN DIRECTLY FROM FREEZER. 
The question of whether a sample of ice cream taken from a I 
freezer represents in bacterial content the entire contents of the 
freezer is one of considerable importance. To obtain information 
on this point 10 series of from 6 to 10 samples were taken from the 
large commercial freezers in an ice-cream plant. The samples were, 
taken in the following manner: As soon as the cream was frozen 
and ready to flow into the final containers for hardening, the gate 
was opened and about 1 pint allowed to flow out. The first sample 
of about 50 grams was then taken by allowing the partially frozen cream 
to flow into a sterile salt-mouth bottle. About 1 gallon of ice cream 
was then allowed to flow out and a second sample taken. The remain- 
ing samples were secured in a similar way, the last one being taken 
from the very last portion. All were immediately iced and taken 
to the laboratory, where they were plated in the manner previously 
described. The results are shown in Table V. 
