View report page

90
No. 5 Ice Cream—5th September, 1922.
Direct Films :
Staphylococci Streptococci, Gram negative cocci and
bacilli all present in considerable numbers. Yeasts also
present—occasional epithelial cells seen.
Quantitative estimation :
Both in cold incubator and at 37 degrees C., the total
count is approximately 80 million bacteria per 1 c.c.
Films from these plates show a strong growth of yeasts
and Gram negative bacilli.
Search for B. Coli Communis and Organisms of the Enterica
group :
Ice-cream, in quantities from lc.c. down to .00001 c.c.,
was inoculated into liquid MacConkey lactose and glucose
media. Acid and gas appeared in all but the lowest
dilution. From those glucose tubes showing acid and
gas, MacConkey plates were made with the following
results:—
Ice Cream, .001 and .0001 c.c.—No growth on MacConkey.
Ice Cream, .25, .1 and .01c.c.—A moderate growth
of both lactose and non-lactose fermenters.
(a) The non-lactose fermenters all gave acid and gas
with saccharose, so serological tests were not proceeded
with.
(b) Lactose fermenters—A number of colonies tested
out. Result, B. Coli Communis present in .25 c.c.
of ice cream—not present in 1 c.c. of ice cream.
Streptococci were absent in all hang drop preparations
from the liquid MacConkey cultures.
No. 6 Ice Cream Scraping—5th September, 1922.
Appearance : A greenish colour.
Direct Films :
Moulds, Yeasts, Staphylococci and Streptococci diphtheroids
and gram negative bacilli present.