34
Sanitizing Dairy Utensils
Recently a product known as Bentonite
(a kind of clay) was brought on the
market, and it was claimed for it that it
was a useful detergent for cleaning dairy
utensils and cheaper* than washing soda.
When Bentonite was tested in the labor-
atory it was found to give alkaline
reaction to phenolphthalein and contained
traces of carbonates as indicated by the
slight effervescence it gave with hydro-
chloric acid and appearance of white tur-
bidity when barium chloride solution was
added to clear water extract of Bentonite.
The following composition of Bentonite
was supplied by the firm:
Moisture
Ignition loss
Silica (SiO 2 )
Alumina (Al 2 O 3 )
Iron oxide (Fe 2 O 3 ) ..
Calcium oxide (CaO) ..
Magnesium oxide (MgO)
Sodium oxide (Na 2 O)..
Potassium oxide (K 2 O)
15.36
7.24
49.53
19.41
0.59
2.62
5.11
0.12
0.03
percent.
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100.01 per cent
In view of its alkaline property and low
organic matter content, Bentonite indicat-
ed the possibilities of its being used as a
dairy detergent suitable for conditions
prevailing in this country. This investi-
gation was therefore undertaken to deter-
mine its quality as a detergent when com-
pared with washing soda, the commonly
used detergent in the organized dairies.
The village method of cleaning milk uten-
sils with mud and cow-dung cake ash
termed as 'indigenous method', has also
been investigated for its bactericidal effi-
ciency as compared with the method adopt-
ed in dairies, namely cleaning with wash-
ing soda using hot water for rinsing
purposes, followed by steam sterilization.
For the purpose of investigation the milk
utensils used were of two types, namely
bottles of 1 lb. and 2 lb. capacity and cans
(brass tinned and untinned) of 1½ gallons
capacity.
*Price of Bentonite
Market price of washing soda
. Rs. 7-8-0 per cwt.
25-0-0 „ „
EXPERIMENTAL
Method of cleaning. The methods em
ployed for cleaning milk bottles and can
with washing soda, Bentonite and indig
enous method were as follows:
(i) Milk bottles. Sterile bottles were
used so as to bring the initial con
tamination to the same extent in al
cases. A measured quantity of raw
milk was then put into these bottles
and kept overnight to curdle. The
following morning the curdled milk
was drained off from the bottles
the bottles rinsed with tap water to
remove the remnants of curdle
milk and then cleaned with the three
detergents as follows:
(a) Washing soda. The bottles were
washed with 1 per cent solution
of washing soda in hot water
(140°F) and scrubbed with a
sterile bottle brush. After this
they were rinsed with hot water
to remove the traces of alkal
and then sterilized in a steam
chest for three minutes.
(b) Bentonite. The procedure follow
ed was the same as above.
(c) Indigenous method. After rins
ing the bottles with tap water
the mixture of mud and cow
dung cake ash in equal
amounts were applied to them
both inside and outside and the
inside then scrubbed thoroughly
with a sterile brush. The bottles
were then rinsed with tap water
till all the traces of mud particles
were removed. Finally they were
rinsed with water and kept
exposed to sunlight for ½ hour
first with their mouths down and
then with their mouths and inside
portions fully exposed to direct
sunlight for an hour.
(d) Controls. The bottles were simply
rinsed with tap water and scrub
bed with a sterile brush till all
the curdled milk particles were
removed. Finally they were
rinsed with tap water.