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77
11 samples of Grade A Milk (Pasteurised) gave exceedingly low bacteria
counts as might be expected from Grade A milk which has been pasteurised.
The coliform bacillus was absent in 1/10 c.c. in each case.
Grade A (Tuberculin tested) Milk and Grade A Milk.—The milk must
not contain more than 200,000 organisms per c.c. and must not contain coliform
bacillus in 1/100 c.c.
15 samples of Grade A (Tuberculin tested) Milk gave bacteria counts
ranging from 600 to 56,500 organisms per c.c.
In 4 of these samples the coliform bacillus was present in one out of three
tubes which is regarded as satisfactory by the regulations, and in 3 cases
from the same producer the coliform bacillus was present in 1/100 c.c. in
all tubes. These 3 samples were therefore unsatisfactory.
1 sample of Grade A milk contained 6,350 organisms per c.c., the coliform
bacillus being absent in 1/100 c.c.
Pasteurised Milk.—The milk must not contain more than 100,000
organisms per c.c. (No test for the coliform bacillus is required).
10 samples of Pasteurised Milk gave bacteria counts ranging from 200
to 109,800 bacteria per c.c. Single tube tests for the coliform bacillus were
also made. In the sample with the highest count the coliform bacillus was
present in 0 00001 c.c. This sample was unsatisfactory
Ordinary Milk.—Owing to a complaint from the L.C.C. that milk obtained
from the South Grove Institution showed high organismal counts and
contained B. Coli, a sample was obtained on delivery at this Institution and
was found to contain 52,200 organisms per c.c. and the coliform bacillus
in 1/100 c.c. (two tubes). There is no standard for ordinary ungraded milk,
and as one positive tube in three is allowed in 1/100 c.c. of graded milk and
no standard for the coliform bacillus is stated for pasteurised milk, the sample
was passed as satisfactory.
The results obtained on the above graded samples show that the majority
of the samples easily comply with the requirements of the Regulations, all
samples of Grade A Pasteurised Milk showing excellent results. Out of the
40 graded samples only 4 Grade A (Tuberculin tested) Milk and 5 Pasteurised
Milk samples exceeded 10,000 organisms per c.c. The standards are too
lenient. Pasteurisation kills practically all the bacteria, only spores and a
few organisms remaining; these could be removed by fractional pasteurisation