NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
124
Detection of Adulteration of Milk with Milk Powder
carried out as described above but before incubating a drop of formalin was added. By this
modification of the test, the distinction between tonned and pure samples became very sharp and
tonned milk could be detected without the slightest ambiguity.
In practice this test has proved to be the simplest and the most sensative test of those tried
for distinguishing milk tonned with milk powder.
(ii) Rennet test. For this test 50 ml. of milk were brought to 37ºC. and 1 ml. of 10 per cent
Hansen's liquid rennet added, while stirring. The time when flakes first appear was noted.
Preliminary studies showed that diluting the milk under test with distilled water helped to differ
entiate between pure and tonned milk. Hence this method was adopted for all the studies described
below. The results in detail are given in Table I to VI. The figures 0, 15, 30, etc., in the heading of
the Table represent the percentage of distilled water added to milk (V/V).
TABLE III
Rennet test with buffalo milk and tonned buffalo milk (roller dried whole milk powder)
(Coagulation time in seconds)
Serial
Number
1
2
3
4
5
6
7
8
9
10
11
12
Average
Fat
S. N. F.
of original raw milk
7.50
5.25
6.90
6.40
5.95
5.70
6.90
6.50
6.15
5.50
5.90
6.50
8.45
8.50
8.50
8.48
8.42
8.38
8.36
8.47
8.37
8.35
8.42
8.36
8.42
Raw samples
Original milk
Tonned milk
Percentage adulteration
0
64
85
76
42
49
56
43
47
71
67
66
60
60
30
59
98
84
40
43
52
34
42
68
71
62
57
59
50
62
112
97
39
25
54
39
41
75
80
58
67
62
0
768
217
412
193
252
182
102
207
357
199
314
323
294
30
917
310
952
261
251
215
107
275
663
264
417
566
433
50
1125
375
1800
330
378
362
128
421
1800
435
777
1409
778
K. N. SHAMA SASTRY AND NOSHIR,
N.
DASTUR
125
TABLE IV
Rennet test with buffalo milk and tanned buffalo milk (roller dried skim-milk powder)
(Coagulation time in seconds)
Serial
Number
1
2
3
4
5
6
7
8
9
10
11
12
Average
Fat
S.N.F.
of original raw milk
6.40
5.75
6.70
5.90
5.95
5.70
6.90
6.15
5.50
6.50
5.70
7.30
8.58
8.53
8.56
8.45
8.52
8.56
8.17
8.60
8.61
842
8.50
8.41
8.49
Raw samples
Original milk
Tonned milk
Percentage adulteration
0
42
78
50
93
49
56
43
71
67
60
56
45
59
30
40
72
48
103
43
52
34
68
71
57
54
44
57
50
39
83
48
144
25
54
39
76
80
67
59
48
63
0
354
597
670
440
444
351
302
563
270
554
383
263
432
30
563
947
1082
944
725
477
405
1008
402
1035
564
333
624
50
1120
1800
1800
1800
911
722
831
1800
795
1800
605
508
786
TABLE V
Rennet test with cow milk and tonned cow milk (roller dried whole milk powder)
(Coagulation time in seconds)
Serial
Number
1
2
3
4
5
6
7
8
9
10
11
12
Average
Fat
S.N.F.
of original raw milk
5.70
4.80
6.45
4.30
4.70
4.30
4.50
5.80
4.65
5.50
5.30
4.70
8.60
8.42
8.50
8.48
8.50
8.38
8.36
8.47
8.35
8.42
8.36
8.45
8.44
Raw samples
Original milk
Tonned milk
Percentage adulteration
0
112
83
35
62
38
36
42
56
78
100
81
99
68
30
138
99
26
63
32
30
36
54
82
111
89
103
72
50
222
128
26
69
31
30
37
57
98
143
116
119
90
0
275
322
185
262
96
96
228
196
222
630
329
345
265
30
375
382
265
372
151
160
391
261
290
1158
617
612
336
50
432
445
482
875
215
275
1247
635
791
1800
1800
1800
900
126
Detection of Adulteration of Milk with Milk Powder
TABLE VI
Rennet test with cow milk and tonned cow milk (roller dried skim-milk powder)
(Coagulation time in seconds)
Serial
Number
1
2
3
4
5
6
7
8
9
10
11
12
Average
Fat
S. N. F.
of original raw milk
4.30
5.95
4.40
4.70
4.30
4.50
4.65
5.30
5.30
5.20
3.90
4.10
8.53
8.56
8.53
8.56
8.56
8.47
8.61
8.42
8.50
8.41
8.49
8.56
8.52
Raw samples
Original milk
Tonned milk
Percentage adulteration
0
62
91
52
38
36
42
78
81
75
69
72
74
64
30
63
106
49
32
30
36
82
89
75
70
77
78
66
50
69
142
48
31
30
37
98
116
86
89
90
79
76
0
148
780
184
63
56
255
281
385
405
298
270
255
282
30
233
1590
203
64
58
444
436
745
646
422
372
385
466
50
280
1800
322
76
61
1130
1040
1800
1410
1036
552
494
833
The following is a summary of the results given above :
(A.) Buffalo milk tonned with spray-dried skim milk powder (Table I)
(i) With raw buffalo milk, the time of coagulation on dilution with distilled water tends to
decrease slightly with 15 and 30 per cent dilution and increases by about 7 per cent with 50 per cent
dilution.
(ii) Under identical conditions of dilution, the time of coagulation of tonned milk increases
as shown by the following average figures :
Original buffalo milk
.
.
.
.
Tonned
„
„
.
..
..
..
.
Tonned milk diluted 15 per cent
„ „ „ 30 per cent .
.
.
.
.
„
„ „ 50 per cent .
.
.
.
.
Milk powder solution
.
..
..
..
.
Average
time of
coagulation
(seconds)
53
85
91
96
136
379
Minimum and
maximum
limits
(seconds)
35
53
55
56
84
285
98
129
133
191
297
650
Percentage
increase
over
original
. .
60.4
71.7
81.1
156.6
. .
Percentage
increase
over
tonned
milk
. .
. .
5.8
12.9
60.0
. .
(iii) Boiled buffalo milk gives an average value of 148 seconds for coagulation (minimum 79
maximum 257) ; i.e., an increase of 179 per cent over the value for raw milk.
K. N. SHAMA SASTRY AND NOSHIR N.
DASTUR
127
(iv) The increase in time of coagulation of boiled buffalo milk with different dilutions were as
follows:
Dilution.
15 per cent
.
.
.
.
.
.
.
.
.
30 per cent . . . . . . . . .
Average time
of coagulation
(seconds)
160
202
Minimum and
maximum limits
(seconds)
84
89
257
453
Percentage
increase over
boiled milk
8.1
36.5
(v) Boiled tonned milk shows the following changes :
Dilution
Boiled tonned milk
.
.
.
.
.
„
„
„
diluted 15 per cent .
„
„
„
„
30 per cent .
Average
time of
coagulation
(seconds)
210
254
402
Minimum
and
maximum
limits
(seconds)
110
112
134
323
403
677
Percentage
increase
over boiled
milk
41.9
71.6
171.6
Percentage
increase over
tonned
boiled milk
. .
20.9
91.4
(B) Cow milk tonned with spray-dried milk powder (Table II)
(i) Raw cow milk shows a distinct increase in time of coagulation with different dilutions as
follows :
Dilution
15 per cent
.
.
.
.
.
.
.
30
„
.
.
.
.
.
.
.
50
„
.
.
.
.
.
.
.
Average time of coagulation
89
101
154
Percentage increase over ori-
ginal milk
3.5
17.5
79.1
(ii) Under identical conditions of dilutions, the time of coagulation of tonned cow milk gave
the following results :
–––
Tonned milk
.
.
.
.
.
.
.
„
„ diluted 15 per cent .
„
„
„
30 per cent
„
„
„
50 per cent
Average time
of
coagulation
116
115
168
284
Minimum and
maximum
limits
45
45
46
72
180
223
357
425
Percentage
increase
over
original
milk
34.9
33.7
95.3
230.2
Percentage
increase
over
tonned
milk
. .
0
46.1
147.0
(iii) Boiled samples take on an average 288 seconds for coagulation, i.e., an increase of nearly
335 per cent over raw milk. The corresponding figure for buffalo milk as mentioned before was
179 per cent.
(iv) The increase in time of coagulation of boiled cow milk with different dilutions were as
follows:
—
Boiled cow milk . . . . . . . . . . . . . . . .
„
„
„
diluted 15 per cent
.
.
.
.
„
„
„
„
30 per cent
.
.
.
.
Average
time of
coagulation
288
477
951
Minimum and
maximum
limits
145
166
194
522
1027
1800
Percentage
increase
over boiled
milk
65.6
230.2
P
128
Detection of Adulteration of Milk with Milk Powder
(v) Boiled tonned milk show the following changes:
Boiled tonned milk
„
„
„ diluted 15 per cent .
„
„
„
„ 30 per cent .
Average time
of
coagulation
367
646
1124
Minimum and
maximum
limit
137
172
244
667
1350
1020
Percentage
increase over
boiled
milk
27.4
124.3
290.2
Percentage
increase over
boiled
tonned milk
. .
76.0
206.3
(C) Cow and buffalo milk tonned with rollerdried milk powders (Tables III-VI)
From the results it is seen that the addition of these particulars brands of roller dried powders
increases the time of coagulation to a very great degree and there is no ambiguity in detecting tonned
milk.
On the basis of the above results a tentative scheme for differentiating genuine, tonned and
boiled milk is given below—
Increase in time of coagu-
lation about 10
per cent
Raw buffalo milk
Sample of milk
Diluted with 50 per cent distilled water
Rennet test
Increase in time of coagu-
lation loss than 100
per cent
Raw cow milk
Increase in time of coagu-
lation 50-150
per cent
Boiled buffalo or tonned buffalo
milk
Within 75 per cent
Tonned milk
Increase in time of coagulation
over 200 per cent. Boiled
cow or tonned cow milk
Rennet test with original milk
after 30 per cent dilution
Time of coagulation over 150
per cent
Tonned milk
This scheme can be still more simplified if it is assumed that under market conditions the analyst
will have to deal with either raw cow, buffalo or tonned milk. In that case the rennet test is carried
out with original milk and of the same milk after 50 per cent dilution with distilled water. The
interpretation of results will be as follows :—
1.
2.
3.
4.
Change in time of coagulation not exceeding 10 per cent .
.
.
.
.
Increase in time of coagulation between 20-50 per cent .
.
.
.
.
Increase in time of coagulation between 75-100 per
cent.
.
.
.
.
Increase in time of coagulation of 200 per cent and
over.
.
.
.
.
Buffalo milk
Tonned buffalo milk
Cow milk
Tonned cow milk
(iii) Estimation of total Residue. A quantity of milk 40 ml. were centrifuged in a weighed
tube for 25 minutes at a speed of 3,000 r.p.m. The supernatent liquid, including the fat layer, were
decanted off without disturbing the sediment at the bottom and drained for 30 seconds. The sides
were wiped carefully with wet cotton-wool to remove any fat sticking to them. The residue was
dried, cooled, weighed and results experessed as gm. 100 ml.
Preliminary trials showed that when working with wet residue concordant results were not
obtained and it was necessary to dry the residue to a constant weight.
The results are given in Tables VII-X.
K. N. SHAMM SASTRY AND NOSHIR N.
DASTUR
129
TABLE VII
Dry residue in tonned buffalo milk (spray-dried skim milk powder) expressed in gm./ 100 ml.
Serial
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
Average
Raw samples
Percentage dry residue
Original milk
0.1062
0.0890
0.0795
0.1147
0.0600
0.0937
0.1160
0.0560
0.0630
0.1195
0.0700
0.0870
0.1302
0.1040
0.0895
0.0700
0 0765
0.0920
0.0475
0.0840
0.0740
0.0830
0.0910
0.0437
0.1230
0.0525
0.1050
0.0560
0.0980
0.0690
0.0912
0.0875
0.0950
0.0785
0.0890
0.0730
0.1190
0.1120
0.0807
0.0802
0.0572
0.0715
0.0522
0.0512
0.0814
Tonned milk
0.1930
0.2270
0.1805
0.2320
0.2120
0.2367
0.2635
0.1877
0.2010
0.2182
0.2530
0.1967
0.2250
0.2015
0.1780
0.1855
0.1805
0.2080
0.1515
0.2305
0.1832
0.1235
0.1630
0.2172
0.1700
0.1637
0.1662
0.0907
0.1470
0.1185
0.1262
0.1372
0.1645
0.1447
0.1990
0.1662
0.1827
0.1880
0.1455
0.1637
0.1177
0.1400
0.1352
0.1125
0.1778
Milk powder
milk used for
tonning
0.4160
0.3440
0.2870
0.3615
0.3345
0 3807
0.3150
0.3590
0.3335
0.3941
0.3170
0.3957
0.3295
0.3015
0.3847
0.3595
0.3375
0.2180
0.2727
0.2780
0.3960
0.3128
0.2820
0.4170
0.3428
Boiled samples
Percentage dry residue
Original milk
0.1095
0.0660
. .
0.1225
0.0535
0.1157
0.1055
..
0.1160
0.1202
0.1520
0.0995
0.0975
0.0960
0.0860
0.1120
0.1505
0.1060
0.0970
0.0740
0.1602
..
0.1235
0.0967
0.1477
0.1150
0.0525
0.1050
0.0965
0.1005
0.0657
0.0900
0.0650
0.1022
0.0945
0.1122
0.1105
0.1125
0.1022
0.1060
0.1005
0.1090
0.1012
0.1035
0.1037
Tonned milk
0.1365
0.1460
..
0.1775
0.1220
0.1430
0.1130
..
0.1500
0.1240
0.2545
0.1500
0.1675
0.1990
0.1390
0.1195
0.0687
0.0570
0.1450
0.1412
0.2259
..
0.1510
0.1185
0.1510
0.1282
0.0765
0.1030
0.1175
0.1890
0.1130
0.0985
0.1050
0.1300
0.1275
0.1482
0.1730
0.1580
0.1222
0.0144
0.1415
0.1380
0.1272
0.1230
0.1325
Milk powder
milk used for
tonning
0.2010
0.1570
..
0.1955
0.1515
0.1515
0.1690
..
0.1920
0.1527
0.2440
0.2005
0.2125
0.2085
0.1635
0.1780
0.2192
0.1740
0.1695
0.1687
0.2768
..
0.2015
0.1457
0.1872
130
Detection of Adulteration of Milk with Milk Powder
TABLE VIII
Dry residue in tonned cow milk (spray-dried skim-milk powder) expressed in gm./100 ml.
Serial
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
Average
Raw samples
Original milk
0.0650
0.0417
0.0980
0.0270
0.0690
0.0630
0.0565
0.0480
0.0645
0.0605
0.0420
0.0580
0.0420
0.0370
0.0775
0.0503
0.0882
0.0797
0.1045
0.0542
0.0502
0.0655
0.0705
0.0690
0.0602
0.0547
0.0670
0.0515
0.0990
0.0582
0.0697
0.0765
0.0677
0.0505
0.0680
0.0397
0.0557
0.0605
Tonned milk
0.1250
0.1150
0.1140
0.0790
0.1560
0.1380
0.1490
0.1410
0.1311
0.1030
0.1260
0.1740
0.1535
0.0727
0.1140
0.0930
0.1110
0.2116
0.1722
0.1412
0.1202
0.1152
0.1150
0.1450
0.0937
0.0982
0.1125
0.1262
0.1455
0.0962
0.1520
0.1190
0.1232
0.1230
0.1100
0.1247
0.1265
0.1261
Milk powder
milk used far
tonning
0.3345
0.3807
0.3150
0.3590
0.3335
0.3941
0.3170
0.3957
0.3295
0.3015
0.3847
0.3595
0.3375
0.2727
0.2795
0.3128
0.2820
0.4170
0.3392
Boiled samples
Original milk
0.0545
0.0475
0.0495
..
0.0740
0.0610
0.0920
0.0725
0.0657
0.1475
0.0512
0.1200
0.1920
0.0920
0.0512
..
0.0685
0.0370
0.0797
Tonned milk
0.0960
01090
0.0885
..
0.0870
0.1097
0.1350
0.1155
0.1250
0.1180
0.1192
0.1300
0.1700
0.1310
0.0962
..
0.0985
0.0975
0.1141
Milk powder
milk used for
tonning
0.1515
0.1515
0.1690
..
0.1920
0.1527
0.2440
3.2005
0.2125
0.2085
0.1635
0.1780
0.1292
0.1695
0.2127
..
0.2015
0.1457
0.1857
TABLE IX
Dry residue in tonned milk using roller dried whole-milk powder expressed in gm./100 ml.
Serial
No.
1
2
3
4
5
6
7
8
9
10
11
12
Average
Raw Buffalo milk
Original
0.0845
0.0795
0.0660
0.0800
0.0575
0.0730
0.0702
0.0550
0.0750
0.0700
0.0140
0.0698
0.0662
Tonned
0.5129
0.7712
0.7750
0.5370
0.7650
0.3800
0.6525
0.4027
0.3444
0.7290
0.4845
0.5335
0.5739
Boiled Buffalo milk
Original
. .
0.0735
0.0815
0.0900
0.1660
0.2447
0.1685
0.1195
0.1730
0.1175
0.1110
0.0965
0.1310
Tonned
. .
0.2690
0.6215
0.2300
0.2135
0.2395
0.1817
0.2425
0.4020
0.3757
0.2280
0.3120
0.3014
Raw Cow milk
Original
0.0507
0.0697
0.0815
0.0587
0.0540
0.0720
0.0700
0.0572
0.0482
0.0635
0.0512
0.0670
0.0620
Tonned
0.6680
0.5150
0.5831
0.5555
0.2865
0.4207
0.2835
0.1862
0.8610
0.2600
0.6540
0.3125
0.4655
P-2
K. N. SHAMA SASTRY AND NOSHIR N.
DASTUR
131
TABLE X
Dry residue in tonned milk using roller dried skim-milk powder expressed in gm./100 ml.
Serial
No.
1
2
3
4
5
6
7
8
9
10
11
12
Average
Raw buffalo milk
Original
0.0800
0.0825
0.0637
0.0525
0.0945
0.0730
0.0702
0.0625
0.0750
0.0700
0.0660
0.0625
0.0710
Tonned
0.3060
0.2812
0.3255
0.4400
1.0530
0.2940
0.6525
0.3660
0.3675
0.7000
0.6620
0.4216
0.4891
Boiled buffalo milk
Original
0.0900
. .
0.1195
0.1073
0.1127
0.1275
0.1685
0.1065
0.1845
0.1115
0.1065
0.1125
0.1215
Tonned
0.2145
. .
0.2037
0.3050
0.2077
0.2447
0.1817
0.2360
0.4020
0.3941
0.2415
0.2368
0.2689
Raw cow milk
Original
0.0670
0.0410
0.0850
0.0566
0.0720
0.0700
0.1070
0.0482
0.0635
0.0615
0.0557
0.0612
0.0616
Tonned
0.1910
0.3292
0.7340
1.1320
0.3037
0.2835
0.3925
0.3620
0.2600
0.5120
0.4062
0.5265
0.4527
It was found that fresh milk samples give values much below 0.10 per cent dry residue in a large
majority of cases and the average varies from 0.060 to 0.081 per cent. There was a great variation
in results obtained from the same class of animals on different days and hence it was not possible to
differentiate between cow and buffalo milk from individual figures. It may further be added that
the studies reported here were carried out with farm produced milk and it is quite likely that market
samples will give higher values for dry residue than those recorded. Compared to raw cow and
buffalo milk, milk powder solutions give much higher values. The average for spray dried skim-
milk powder was 0.34 per cent. Tonning raw milk invariably gives a higher figure. When roller
dried milk powders are used tonning can be detected without any difficulty as the percentage of dry
residue increases from less than 0.05 per cent to nearly 0.5 per cent.
When spray dried powder is used the percentage of dry residue does increase but the demarca-
tion is not so sharp. For guidance it is suggested that if the percentage of residue is greater than
0.11 per cent the possibility of the sample being tonned may be tentatively assumed and confirmed
by the following further tests :
(a) The dry residue may be estimated on the sample after it has been boiled. It has been found
that milk samples give a higher percentage of residue after boiling. On the contrary tonned milk
(as well as spray dried skim milk powder) shows the reverse, i.e., on boiling the amount of residue
usually decreases, probably due to the fact that on boiling some more of the residue goes into solution.
(b) The dry residue is subjected to the xantho-protein reaction. The residue is dissolved in
2-5 ml. concentrated nitric acid, diluted with 5 ml. of water and then 2.5 ml. liquor ammonia added.
It was observed that the residue from pure milk gives a solution with a yellow colour, milk powder
residue gives a deep orange solution, while tonned milk samples give a colour varying from light orange
to orange. The results are given in Table XI.
132
Detection of Adulteration of Milk with Milk Powder
TABLE XI
Xanthoprotein reaction with dry residue
Serial
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Buffalo milk tonned with spray dried skim-milk powder
Raw samples
Original
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
+
+
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
+
Y
Y
Y
Y
Tonned
+
+
+
+
+
+
+
+
+
+ +
+ +
+ +
+
+ +
+
+ +
+
+ +
+
+ +
+ +
+ +
+
+
+ +
+
+
+
+
+
+ +
+
+
+
+
Y
+
+
+ + +
+
+
+
+ +
Milk
powder
milk
used for
tonning
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ + + +
+ + + +
+
+ + +
+ + + +
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Boiled samples
Original
+ +
Y
—
Y
Y
Y
Y
—
Y
Y
Y
+
Y
+
+
Y
+
Y
Y
—
+
+ +
Y
Y
+ +
+
Y
Y
Y
Y
Y
Y
Y
Y
Y
V
Y
Y
Y
Y
Tonned
+ + +
+
+ +
—
+ + +
+
+
+
—
+
+ +
+ +
+ +
+ +
+ +
+
+ +
+ + +
+ + +
+ + +
+ +
+ +
—
+
+ + +
+ +
+
+
+ + +
+
+
+ +
+
+
+
+
+
+
+
Y
+
+
+
Milk
powder
milk
used for
tonning
+ + + +
+
+
+
+
—
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
—
+
+
+
+
+ + + +
+ + + +
+ + + +
+ + + +
+
+
+
+
+ + + +
+ + + +
+
+
+
+
+
+
+
+
+ + + +
—
+
+
+
+
+
+
+
+
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Cow milk tonned with spray dried skim-
milk powder
Raw samples
Original
+
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
—
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
+
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Tonned
+
+ +
+
+ +
+ + +
+
+ +
+
+ +
+ + +
+ +
+ +
+ +
+
+ +
+ +
+ +
+
+ +
+ +
+ +
+ +
+ +
+ +
+ +
+ +
+ +
+
+
+ +
+
+
+ +
+
+
+ + +
+
+
+
+
+
+ +
Y
+ +
+ +
+
Boiled samples
Original
+ +
Y
—
Y
Y
Y
Y
—
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
—
Y
Y
Tonned
+
+ +
+ -I-
+
+
+ +
+
+
+
+
+
+
+ +
+ +
+ +
+ +
-I- +
+
+ +
+ +
Y = Yellow
+ = Yellowish orange
+ + = Light orange
+ + + = Orange
+ + + + = Deep orange
— = Test not carried out
This test formed a useful and simple means of distinguishing pure and tonned milk. In the
Table XI results of experiments with spray dried skim milk powder alone are given. However,
these conclusions have been confirmed when using roller dried powers also.
K. N. SHAMA SASTRY AND NOSHIR N. DASTUR
133
(iv) Other tests tried. Besides the ones indicated above, original and tonned milk samples were
subjected to the following tests:
a. Freezing point determination
b. Microscopic study
c. Methylene blue reduction test
d. Resazurin test, and
e. Estimation of total minerals
None of these tests helped to clearly differentiate between various samples of milk and hence
detailed results are not given here.
SUMMARY
The following nine methods were tried for differentiating genuine milk from tonned milk :
(1) Stability to heat
(2) Coagulation with rennet after dilution with water
(3) Estimation of dry residue
(4) Xanthoprotein reaction with dry residue
(5) Freezing point
(6) Microscopic study
(7) Methylene blue reduction test
(8) Resazurin test, and
(9) Estimation of total minerals
Studies have been carried out using spray dried skim-milk powder, roller dried skim-milk powder
and roller dried whole milk powder.
Amongst the tests tried microscopic study, methylene blue test, resazurin test, freezing point
and estimation of total minerals have proved of little value.
The odour of samples after incubation for four hours at 37°C. provides the simplest and a very
reliable test. Incubation is carried out after adding a drop of formalin to suppress the development
of lactic acid odour. This test can be done under house-hold conditions.
The rennet test after diluting the milk sample with distilled water is another simple test and
the results can be obtained in a short time. Tonned milk takes a much longer time to coagulate.
Cow and buffalo milk are found to differ to some extent in their behaviour towards rennet. Cow
milk takes a longer time and also the time of coagulation markedly increases on dilution with water.
The estimation of dry residue is another test which will prove useful. It is likely that the figures
for dry residue obtained in the present studies may require some modification when working with
market samples. The results of this test are further confirmed by the xanthoprotein reaction with
the dry residue. Pure milk gives a yellowish coloured solution, whilst tonned milk samples give an
orange colour.
ACKNOWLEDGEMENT
The authors wish to express their thanks to the Imperial Council of Agricultural Research for
giving special grants to complete these studies.
138
Study on the Haematology of Dogs in Health
SUMMARY
This paper records the results of studies made to determine the total red and white cell counts,
the differential white cell counts, and the haemoglobin content of the blood of dogs during health
and during piroplasmosis (B. gibsoni infection) of there apparently healthy dogs between two to
four years of age, two of which were infected artificially with the parasites and the third was used
as a control. Morphological studies and haemoglobin estimations were made of the blood of these
animals before infection and also during the disease. In the two infected dogs the readings did
not change significantly during the incubation period.
For comparative purposes seventeen (17) counts were made on the blood of 10 apparently healthy
pariah dogs with results similar to those obtained in the case of the experimental dogs before infec-
tion was established.
In the two infected dogs the red cell count fell to about one million per c.mm. during the disease.
The white cell count increased to a peak at nearly 80,000 per c.mm. and this was followed by a gradual
decrease to almost normal level, irrespective of whether the disease ended in death or recovery. The
differential white cell count showed during a period of marked leucocytosis a mild neutrophilia ,
slight lymphopenia, eosinopenia, and a shift to the left of the neutrophiles and this was followed by
a moderate monocytosis. During the disease the average haemoglobin content dropped to 12.5
per cent from normal.
The outstanding features of B. gibsoni infection in dogs are the decrease in total red cell count
and the marked fall in haemoglobin due to a certain extent to rapid destruction of the red cells, but
more to the failure of formative tissues.
ACKNOWLEDGEMENT
My thanks are due to Dr F. C. Minett for examining and correcting the paper. The work was
done under the instructions of Dr S. C. A. Datta.
REFERENCES
Dukes, H. H. (1935). The Physiology of domestic animals, 4th. Ed.
Gaiger, S. H. and Davies, G. O. (1938). Veterinary Pathology Bacteriology. Bailliere, Tindall & Cox, London.
Khanawa, Chush (1928). Folia Haematologica 36, 174 (Abs. in Veterinary Record, 8, 863, 1928)
Nicols, R. E. (1935). Vety. Med. 30, 289
Piney, A. (1931). Recent advances in haematology, 2nd Ed., J. R. Churchill, London