K. K. DESAI, G. S. THAKRE AND K. C.
SEN
265
therefore, be bleached with animal charcoal (10
per cent for 20 seconds) prior to a viewing of the
colour.
3. Old and rancid ghee gives progressively blue
shades: most adulterants of ghee also fluoresce
blue. Therefore any suggestion of a blue tint in.
a bleached ghee indicates either bad quality or
adulteration.
ACKNOWLEDGEMENT
The work was done under a scheme financed by
the Imperial Council of Agricultural "Research to
whom our thanks are due.
REFERENCES
Banks (1944). J. Soc. chem. Ind. 63, 8
Dan, Kon and Moore (1937). Milk and Nutrition 1, 45
Haitinger, Grengros and Schultz (1927). Chem. ztg.
51, 527
Jha (1939). J. Ind. chem. Soc. 1, 159
Morgan and MacLennan (1928). Biochem. J. 22, 1514
Muster and Willoughby (1929). Oil and Fat Industry 6,
15
Muthanna and Mukherji (1940). Curr: Sci. 9, 120
Narasimhamurthy and Suryanarayanamurthy (1940). Curr,
Sci. 57, 339
Radley (1933). Analyst 58, 527
Radley and Grant (1938). Fluorescence Analysis in Ultra-
violet light, 148
Willstatter and Stoll (1928). Investigations on Chlorophyll
(translated), 128
STUDIES IN THE TRANSPORT OF MILK IN WARM CONDITION FOR MAR-
KETING PURPOSES
I. KEEPING QUALITY OF FARM-PRODUCED AND PROCESSED MILK
By K. K. DESAI, G. S. THAKRE AND K. C. SEN. Imperial Dairy Research Institute, Bangalore
(Received for publication on 17 September 1945)
IT is now recognized that in hygienic supply of
milk from rural areas to urban population refri-
gerated system of transport occupies a most promi-
nent position. Unfortunately under present con-
ditions, this involves high initial cost as well as
high recurring expenditure. Since the chief cause
of spoilage of milk is bacterial contamination, it is
desirable to find out if other methods of treat-
ment such as heating the milk to the pasteurizing
temperature, which destroys a major portion of
the organisms, coupled with its transportation in
a hot condition would be successful in preventing
the spoilage. The idea is not a new one as Bern-
stein [1893] claimed good results in the. transport
of hot milk at 70ºC. between Hamburg and Berlin,
a railway journey of 10 hours. On the other hand,
Ayers and Johnson [1923] reviewed the position
and came to the conclusion that milk could not
be kept in a good condition for 24 hours at a tem-
perature of 50°-60°C. because of the growth of ther-
mophilic bacteria. No record of similar work carried
out in India under controlled conditions is available,
but it is reported that it is a common practice adopt-
ed by some Military Dairy Farms to issue hot milk
(145ºF.) to customers during summer months.*
The milk handled in this way is probably consumed
in a few hours' time. Another method, practised
by the halvais, specially in northern India, is to
keep the milk simmering for 7-8 hours and then
dispose it of as demanded by the customers. In
this method, there is no doubt that considerable
chemical changes are brought about.
* Report on the marketing of milk, 1943
As the. 'holding' method of pasteurization,
in which milk is heated to 145ºF. and held at that
temperature for half an hour, is considered to be
suitable for destroying most of the organisms, it
is probable that if this heated milk is kept at more
or less the same temperature, the stability of the
milk will be prolonged for a sufficiently long period,
so that it can be transported over long distances
without giving rise to undesirable chemical changes,
If this is so, much of the expenditure on refrigeration
could be avoided and the cost of transport is likely
to be reduced. In order to obtain some definite
information on the subject, systematic experi-
ments have been started in these laboratories and
in the present communication, some results on the
keeping quality of farm-produced milk at elevated
temperature as compared to milk heated to 150ºF.
and retained at that temperature for half an hour,
cooled and then stored at low (48º-50ºF.) temperature,
are given.
EXPERIMENTAL
Experiments were carried out on a laboratory
scale and then some trials were made on a large
scale. The experimental work was divided as
follows :—
(i) Storage of processed milk at high (150ºF.)
and low (48º-50ºF.) temperatures for eight hours
in glass milk bottles.
(ii) Storage of processed milk at high (150°F.)
and low (48º-50ºF.) temperatures for 16 hours in
small aluminium cans.
C 2