Z. E. KOTHAVALLA, M. S. PHERWANI AND E. V. SESHACHARYULU 35
(i) Cans. To start with all the cans
were thoroughly cleaned with wash-
ing soda and then steam-sterilized
for five minutes along with their
lids. The initial cantamination of
these cans when examined bacterio-
logically showed that their plate
counts varied from 100 to 400 and the
coliform organisms were absent in
one ml. of the rinsed out solution in
all the trials. A measured quantity
of raw milk was then put into each
of these cans and kept overnight to
curdle. The rest of the procedure
adopted in cleaning the cans by the
different methods was the same as
that followed in the case of bottles
excepting that the cans and their
lids were steam sterilized for four
minutes after cleaning with washing
soda and Bentonite. Sterile coconut
coir was used for scrubbing the
cans.
BACTERIOLOGICAL EXAMINATION
(i) Bentonite. Plate counts showed 56,000
bacteria per gram of Bentonite.
(ii) Mixture of mud and cow-dung cake
ash. The bacterial counts varied
from 12 to 15 millions per gram of
the mixture (mud and cow-dung cake
ash) used.
(iii) Tap water. The tap water used for
washing the bottles and cans gave
640 colony counts per ml.
(iv) Bottles and cans. The technique
employed for determining the bac-
terial counts of bottles and cans was
the same as that suggested by Mat-
tick and Hoy [1937] with the excep-
tion that saline solution was used
instead of Ringer's solution for rins-
ing the utensils. In the case of cans
100 ml. of saline water were used
for rinsing. Presumptive coliform
test was done by introducing one
ml. of the rinsed out solution into
10 ml. of MacConkey's bouillon.
The maximum, minimum and average
counts of bottles and cans and the number
of trials in eah case falling between diffe-
rent ranges of counts are give in Table I.
DISCUSSION
The foregoing results show that the
bacterial counts of the bottles treated with
washing soda and Bentonite are not
much different and they are less than
those of the bottles cleaned by the indig-
enous method. The counts of the bottles
cleaned by the indegenous method are less
than those of the controls. With the
washing soda the counts of the bottles
range from 0 to 190, with an average
count of 95, and from 150 to 280, with an
average count of 226, in the cases of 1 lb.
and 2 lb. bottles respectively. The bac-
terial counts of bottles cleaned with Ben-
tonite vary from 0 to 190, the average
count being 85, in the case of 1 lb. bottles
and from 150 to 280, with an average
count of 230, in the case of 2 lb. bottles.
The counts of the bottles obtained by the
indigenous method range from 130 to
2,000, with an average count of 504 in the
case of 1 lb. bottles and from 1,100 to
4,700, the average count being 3,034 with
2 lb. bottles. The plates count of the con-
trol bottles vary from 2,000 to 50,000
with an average count of 9,410 with 1 lb.
bottles and from 5,300 to 75,000, with an
average count of 18,069, in the case of 2
lb. bottles. Coliform is absent in all the
trials with washing soda and Bentonite,
but in the case of indigenous method it is
present in 11 trials with 1 lb. and 2 lb.
bottles. All the controls show positive
test for coliform. The American Standard
Methods [1939] recommend a maximum
of 1, 000 colonies per quart (American)
bottle and of 500 per pint bottle, whereas
Mattick and Hoy [1937] suggested that
200 organisms per pint bottle should be
the standard. All the results with 1 lb,
and 2 lb. bottles cleaned with washing
soda and Bentonite therefore attained
these standards. In the case of indig-
enous method 16 trials with 1 lb. bottles
attained American standards and only six
trials came up to the standard proposed
by Mattick and Hoy. All the trials with 2
lb. bottles cleaned by the indigenous
method and the controls, however, failed
to attain these standards.