P. GAJ RAJ SINGH, et al
241
number below 20 is as low as 5, and beyond 62 per cent alcohol this percentage is negligible. In the
alcohol test it is a common observation that as the quality of milk deteriorates the sample gives a
p itive alcohol test with lower and lower concentration of alcohol. Similarly Ramsdell et al.
[1931] have reported that samples with phosphate number below 20 are less stable to heat. In view
of the findings of the present investigation these two tests could be put together to assess the quality
of the milk sample under investigation.
Table I shows the individual and other variations in the phosphate number so far as buffalo
milk is concerned. For fresh individual samples of milk, figures as low as 10 and as high as 82 have
been met with, but such figures are very few, so that the mean is always far from both of these. In
most of the individual samples, it is found, that there is a gradual increase in the phosphate number
as the lactation advances, although this increase is not maintained towards the end of the lactation.
Almost the same tendency is observed in the case of the composite cow and buffalo samples. There
is considerable daily variation in the phosphate number of the individual milk samples although this
is not so very marked in the case of the composite sample. The weekly average of the phosphate
numbers has never been below 20, although it has touched 20 at times. This shows that there are at
least a few samples which fall below 20. Ramsdell et al. [1931] have reported that cow milk samples
with phosphate numbers below 20 have a low heat stability. From Table I it is seen that buffalo
composite milk has got a higher phosphate number when compared to cow composite milk. Pro-
bably this may be due to the difference in salt distribution balance.
SUMMARY
1. The various commonly used platform tests like the acidity, alcohol and phosphate tests have
been studied from the beginning of one lactation for nearly six months in the case of individual buffalo
milk samples.
2. The inter-relationship between the various tests has been investigated and discussed.
3. There is considerable variation in the acidity of the samples from individual to individual
and from day to day.
4. The alcohol test requires modification by way of reducing the concentration of the alcohol,
to be used for buffalo milk. A concentration of 60 per cent alcohol by volume is recommended for
buffalo milk.
5. There is found to be wide variation in the phosphate number of individual buffalo milk samples.
6. An increasing number of samples with high titratable acidity have a phosphate number below
20.
7. A good proportion of the samples giving a positive alcohol test with 60 per cent alcohol were
found to have a phosphate number 20 or below.
ACKNOWLEDGEMENTS
Our thanks are due to Dr N. N. Dastur and Dr K. C. Sen, for their kind interest in this work,
REFERENCES
Dahlberg, A. O., and Garner, H. S. (1931). Bull. U. S. Department of Agri. 944, 13
Ramsdell, C. E., Johnson, W. J. and Evans, F. R. (1931). J. Dairy Sci., 14, 93
Rogers, L. A., Deysher, E. F. and Evans, F. R. (1921). J. Dairy Sci., 4, 294
Sommer, H. H. and Binny, T. T. (1923). J. Dairy Sci., 6, 176
Sommer, H. H. and Hart, E. B , (1926) Wis. Agr. Exp. Sta. Bull. 67, 47
H