228
Milk produced under Different Conditions in Bangalore
On the supply side (Table II) 56.29 per cent.
of the cow and buffalo milk samples drawn from
the Imperial Dairy Institute dairy showed
between 50,000 and 200,000 bacteria per ml.,
including a large proportion between 100,000
and 200,000. The remaining showed between
200,000 and 500,000 bacteria per ml. Taken
separately the proportions of cow milk samples
below and above 200,000 bacteria per ml. were
54.66 per cent and 45.33 per cent and of
buffalo milk samples 58.72 per cent, and 41.66
per cent respectively. A majority of samples
of travelling milch cows (74.08 per cent) was
below 200,000 bacteria per ml. including a
large proportion below 100,000. Of the remain-
ing samples, a negligible number was between
500,000 and 1 million bacteria per ml. Very
few samples of milk hawkers showed between
200,000 and 500,000 bacteria per ml., the
majority falling between 500,000 and 1 million
and an appreciable number between one and five
millions bacteria per ml. All the samples of
town dairies contained above one million
bacteria per ml., 71.29 per cent of the samples
having between 1 and 10 millions and the re-
maining above 10 millions. The highest record
ed was about 92 millions.
The methylene blue reduction times of a
majority of samples drawn from the Imperial
Dairy Institute dairy were between 240 and 329
min. (45½ hr.). The remaining were above 329
mm. except the one sample which decolourized
between 180 and 239 min. (3-4 hr.). Almost the
same results were obtained with the samples
of travelling milch cows. The majority of
samples of milk hawkers decolourized between
60 and 179 min. (1-3 hr.) and the reduction
times of the remaining were between 180 and
239 min. (3-4 hr.); only one sample decolourized
within 60 min. The reduction times of all the
samples of town dairies were below 119 min.
the majority decolourizing within 60 min. A
very small number of samples fell between 120
and 179 min. (2-3 hr.).
The above results as judged on the basis of a
majority of samples of each class show consider¬
able differences in the bacteriological quality of
milk occurring under the different conditions of
production and supply. A general comparison is
given in Table III.
TABLE III
Source
Production
(1) Imperial Dairy Institute Farm—
(a) Individual animals
.
.
.
.
(b) Herd
.
.
.
.
.
.
(2) Domestic cows
.
.
.
.
.
(3) Town milk stables
.
.
.
.
.
(4) Village
.
.
.
.
.
.
.
.
Supply
(1) Imperial Dairy Institute Dairy . . .
(2) Travelling milch cows
.
.
.
.
(3) Milk hawkers . . . . . . . .
(4) Town dairies . . . . . . . .
Bacterial count per ml.
Below 50,000 . . .
Below 100,000
.
.
.
Below 100,000 . . .
Between 200,000 and 5 millions
Between 500,000 and 10 millions
Below 500,000 . . .
Below 500,000 . . .
Between 500,000 and 5 millions
Over one million (Maximum
recorded over 90 millions)
Methylene blue reduction time
Over 330 min. (5½ hr.)
240 to 330 min. (4 to 5½ hr.)
240 to 330 min. (4 to 5½ hr.)
120 to 330 min. (2 to 5½ hr.)
60 to 240 min. (1 to 4 hr.)
Above 4 hr.
Above 4 hr.
Below 180 min. (3 hr.)
Below 120 min. (2 hr.)
It will be seen from Table III that, amongst
the samples of production milk obtained from
individual animals on a modern dairy farm (the
Imperial Dairy Institute) gave the lowest
bacterial count and highest reduction time, and
the herd milk and domestic cows' milk came
next, followed by milk from town milk stables
and village milk. On the supply side, milk
from the dairy farm and travelling milch cow
gave lower counts and higher reduction times
than the supplies of milk hawkers and town
dairies. It is obvious that the methods of pro-
duction and handling obtaining at the different
sources which have already been described have
tended to give varying bacterial counts and re-
duction times. The very high counts of milk
from town stables and villages are evidently due
to unclean methods. The same can be said of
the milk hawkers and town dairies. The time
elapsing between production and supply, un-
favourable temperature conditions and conta-
mination during haulage and distribution are the
other contributing causes in these cases.
The methylene blue reduction test has
received considerable attention overseas. It is
now employed in the legal control of market
milk in Great Britain. It is considered a
simple, quick and cheap test and much work
has been done on it to determine whether any
correlation exists between the reduction time
and plate count. In making this study the re-
sults given in Table I show that, while there