267 
\\j ■ 
' Tlie experiments cited are too few to permit of formulating definite conclu- 
sions and it must not be forgotten that, purchased as they were — in open] 
market — their histories unknown, there may hare occurred a considerable part 
I of the bacteriological cycle before the specimens were investigated. The results 
i given simply show what may happen to commercial ice cream if kept for from 
, ji three to ten days. 
Two experiments have been made to test the action of freezing and thawing. 
, !; For this work cream was obtained from a milk dealer, sweetened and flavored 
with vanilla in the laboratory, and frozen in a small hand freezer, which had 
I been cleansed simply with hot water. After freezing the product was packed 
I' down in an ice-salt mixture and allowed to stand until the cream had thor- 
'• oughly melted, though the temperature was still considerably below that of the 
surrounding atmosphere. It was then refrozen and again allowed to stand for 
some hours. At each step the bacterial count was made and recorded, as seen 
I . in Table II. Experiments of this character are of interest, not only for the trac- 
ing of decrea.se in numbers, but also as a possible source of information regard- 
,|j ing the many cases of ice-cream poisoning blamed upon stale ice cream, and 
' particularly that which had been melted and refrozen. 
! Table I . — Growth of bacteria in ice cream at the temperature of ice and salt 
{-21° C. = -5.8° F. ). 
K SERIES I. 
Total number of organisms in — 
Source of ice cream. 
1 gram of 
fresh ice 
cream. 
1 1 gram after 
18 hours. 
1 gram after 
42 hours. 
1 gram after 
66 hours. 
No. 1— Manufacturer, sample sent directly j 
r a 811, 249 
ol, 010, 509 
0 3,349,733 
o 4, 405, 286 
from factory 1 
1 &2, 523, 886 
61,010, 509 
6 628,074 
61,664,218 
No. 2— Manufacturer, sample sent directly 
f 0 4,142,068 
0 2,552, 676 
o2, 603,421 
o 4, 550, 050 
from factory 
1 & 9, 521, 995 
61,495, 066 
6464,000 
6 3, 993, 933 
No. 3— Manufacturer, sample sent directly 
r 0 3,375,527 
0 4, 173,622 
0 1,055,966 
o4, 264, 870 
from factory... 
1 69,493,670 
6936,065 
6 422,386 
616,835,016 
SERIES II. 
Source of ice cre^m. 
Total number of organisms in — 
1 gram of 
fresh ice 
cream. 
1 gram after 
24 hours. 
1 gram after 
48 hours. 
1 gram after 
96 hours. 
1 gram after 
192 hours. 
No. 4— Low-grade confectioner. 
No. 5 — Wholesale milk com- 
pany and dairy lunch 
r 0 564,381 
i 61,097,408 
f 01,006,904 
{ 65,418,105 
0164, 000 
6201,786 
01,489,361 
6 2, 765, 957 
0140,814 
61,804, 180 
01,171,613 
62,454, 809 
0 149, 812 
62, 536,115 
0 816,405 
6 3,936, 242 
0 61,312 
61,021,867 
0 236,709 
SERIES III. 
Total number of organisms in — 
Source of ice cream. 
1 gram of 
fresh ice 
cream. 
1 gram after^ gram after 
24 hours, j 48 hours. 
1 gram after 
72 hours. 
1 gram after 
120 hours. 
1 1 
1 gram after 
216 hours. 
1 
No. 6 — Cheap restaurant 
1 a 2, 668,777 
a 298, 804 
a 709, 442 
a 690,000 ' 
a 292, 839 
a 153, 351 
which buys from manu- 
1 5 6,219,608 
fa 12,460, 196 
51,090,637 
5 855, 503 
51,189,296 i 
5 2,352,163 
5 946, 611 
facturer of sample No. 1. 
No. 7 — Small bakery, prem- 
a 3, 231, 017 
a 4, 019, 523 
a 12, 735, 849 
a 8, 052, 455 
a 644, 329 
ises clean 
[529,558,355 
5 2,670,974 
5 8,010, 335 
5 2, 452, 830 
5 2, 300, 701 
5 5, 257, 731 
No. 8 — Market-house lunch 
1 a 510, 673 
a 1, 256, 645 ' 
a 1,424, 936 
a 776, 196 
a 476, 338 
0 219,499 
counter, ice cream made 
I 5 714,942 
5 2,319,961 j 
51,323,155 
5 217, 335 
51,449, 725 
51,005,615 
by proprietor 
I 
a 37° C. 
b 18° to 20° C. 
