NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
12
STUDIES ON DAHI :––1. INTRODUCTION
Kaviratna, A. C. (1922). The Kalpasthana of Charaka Samihta, 200, Cornwallis St., Calcutta
Kazaryan (1936). (Cited by Tanner, 1944, 570)
Kazberyuk, N. A. (1940). Chem. Abstr., 36, 2584
Khambatta, (Miss) J. S. and Dastur, N. N. (1950). Indian J. Dairy Sci., 3, 147
Khoury and Rist (1902). Ann. Inst. Pasteur, 16, 65
Kliewe and Schuppener (1937). Centabl. Bakt., (1) Orig., 138, 180
Knaysi, G. (1932). J. Dairy Sci., 15, 71
Kon, S. K. and Henry, K. M. (1949). J. Dairy res., 16, 68
Kopeloff, N. (1923). J. Amer. Med. Assoc. 80, 602
(1925). Soc. Exp. Biol. & Med. Proc., 22, 393
Lonergan and Beerman (1925). Ibid., 23, 25
Lynch (1928). Amer. J. Med. Sci., 176, 547
Madhok, M. R. and Kapoor, S. L. (1942). Indian J. vet. Sci., 12, 213
Mattick, A. T. R. (1946). Lancet. 250, 417; Dairy Sci. Abst., 6, 191 ; 9, 50
Metschnikoff, E. (1901). Mem. Proc. Manchester Lit. Phil. Soc, 45, No. 5. 1
Myers, R. P. (1931). Amer. J. Pub. Health, 4, 21, 867
Nicholls and Associates (1939). Ceylon J. Sci., & D, 5, 17
Olsen-Sopp, O. J. (1912). Contbl. Bakt., Pt. 2, 33, 1
Orla Jensen, S. (1942). The Lactic Acid Bacteria, 2nd Ed., Danish Royal Academy of Science,
Copenhagen
and
Spur. B. (1924). Le Lait, 4, 845 (Chem. Abstr., 1925, 19, 1460)
Pasricha, C. L. and Associates (1938). Indian Med. Gaz. 73, 94
Ram Ayyar, C. S. (1928, a). Agri. J. India, 23, 107
(1928, b). Agri. Res. Inst., Pusa, Bull. 183
Ranganathan, S. and Narasimhamurthy, G. (1938). Agric. Live Stock in India, 8, 411
and
Associates (1937). Indian J. med. Res., 24, 684
Rangappa, K. S. and Banerjee, B. N. (1946). Ibid., 19, 98
Rettger, L. F. (1915). J. Exp. Med., 21, 365
(1917). Sci. Mo., 1917
(1923). Proc. World's Diary Congress, 2, 1120
Rogers, L. A. (1915). U. S. Dept. Agri., Washington Bull. 309
Rogers, L. A., The Associates of (1925). Fundamentals of Dairy Science, Olsen Pub. Co., Mills-
waukee, Wis.
Rosell, J. N. (1933). Canadian Pub. Health J., 24, 344
(1935). Milk Dealer, 41
Sircana (1937). Cited by Tanner (1944), 569
Smith (1924). Brit. Med. J., No. 3334, 943
Tanner, F. W. (1944). Microbiology of Foods, 2nd Ed., Garrard Press, Champaign, III
Van Slyke, L. L. (1928), N. Y. State Agric. Exp. Sta., Geneva, Tech. Bull. 140
Voitkevich (1934). Proc. World's Dairy Congress, Milan, 238
Wegner M. I. and Associates (1940). Proc. Soc. Exp. Biol., Med., 45, 769
Welch. A. D. and Wright, L. D. (1943). J. Nut., 25, 555
White House Conference on Child Health and Protection (1932). Milk Production and Controls
Century Co., New York
STUDIES ON DAHI*
II. GENERAL SURVEY OF THE QUALITY OF MARKET DAHI
H. LAXMINARAYANA, V. K. N. NAMBUDRIPAD, N. V. LAKSHAMI, S. N. ANANTA-
RAMAIAH AND V. SREENIVASAMURTHY, Indian Dairy Research Institute,
Bangalore
(Received for publication on 8 January 1951)
THE object of the survey was to obtain information on the composition, flavour,
texture and microbial content of dahi produced in different parts of the country.
For this purpose, several zones, broadly representing the different climatic and
other natural conditions in the country and also including areas famous for quality
of dahi, were marked out on the basis of information supplied by provincial autho-
rities and private sources. The research workers visited important urban centres
as well as rural areas in the different zones and collected representative samples of
dahi and lassi from dairies, halwais, street vendors, private houses and other sources.
The programme for the collection of samples from different zones was so arranged
as to cover all the seasons of the year. Altogether about 1,000 samples of dahi and
lassi were secured for the investigation from the following centres (Table I).
TABLE I
Geographical distribution of dahi samples collected for the investigation
Zone
North Indian plains
Sea Coast areas
Deccan Plateau (South India)
Areas of high altitude
Centres
Patna, Muzaffarpur, Darbhanga (Tirhut Valley),
Gorakhpore
Allahabad, Banaras, Lucknow, Kanpur, Mathura,
Agra
Delhi, Meerut, Aligarh, Khurja
Karnal, Ambala, Ferozepur, Hissar
Lahore, Lyallpur
Nagpur, Bhusaval
Hyderabad (Sind)
Ahmedabad, Baroda
Cuttack, Vijayavada
Bombay
Calcutta
Karachi
Madras
Poona
Hyderabad (Dn.)
Bangalore, Mysore, Mandya. Hassar
Coimbatore
Dehra Dun*, Hardwar, Rishikesh
Mahabaleswar
Number
of
samples
60
159
104
72
50
23
19
26
16
116
74
42
40
20
24
73
17
45
15
* Investigations carried out under a research scheme financed by the Indian Council of Agricul-
tural Research, New Delhi.
13
4
14
STUDIES ON DAHI : II—GENERAL SURVEY
[Vol. XXII, Part I
METHODS
Collection of samples
All samples were collected in sterile, glass stoppered 8 oz. bottles, after mixing
well the lots of dahi from which they were drawn. After their preliminary examina-
tion on the spot, such of the samples believed to be representative of the locality
were securely packed in specially constructed insulated wooden boxes and despatched
to Bangalore for further analysis.
Since the samples of dahi were to be utilised for chemical analysis as well as for
the isolation of lactic acid bacteria, the transportation to Bangalore of the samples
in their original condition presented some difficulties, particularly in the case of
more distant centres. The use of insulated ice boxes for this purpose was not found
to be practicable. The samples intended for chemical analysis were, therefore,
preserved by adding 0.5 ml. of a 40 per cent solution of formaldehyde to each half
pound sample of dahi. Preliminary trials showed that with such an addition, the
acidity, fat, protein and ash values of the samples were not appreciably altered on
keeping the sample for 5 to 6 days at room temperature (25±30°C). Lactose
determinations were not made on these samples. For bacteriological work, in
addition to using the original unpreserved sample, a small amount of the sample
was inoculated into dextrose agar stabs. In the case of such samples of dahi as
were believed to require careful bacteriological examination, duplicate stabs were
made of the original samples to guard against any possible mishaps.
Preliminary examination of the samples
A preliminary examination of dahi samples was made at the sources of collection
in regard to (i) their physical appearance, texture and flavour and (ii) microscopic
appearance of smears, which were fixed, defatted with xylol and stained with borax
methylene blue for estimating the types and relative numbers of organisms present
in the samples.
Wherever laboratory facilities permitted* the titratable acidity and total
bacterial counts of the samples were also determined according to the following
procedures.
(a) Titratable acidity. Ten grams of dahi was emulsified in 40 ml. of distilled
water and titrated against 0.1 N/NaOH using phenolphthalein as indicator. - The
results were expressed as per cent lactic acid.
(b) Total bacterial count. The total bacterial counts were determined by using
suitable modifications of standard methods (British Ministry of Health, 1939).
*Laboratory facilities were provided at the Veterinary Colleges in Madras, Calcutta, Patna,
Lahore and Bombay; Agricultural College, Coimbatore; Provincial Hygiene Institute, Lucknow;
Agricultural Institute, Allahabad; Cattle Farm, Hissar; Indian Agricultural Research Institute,
New Delhi; Medical College, Mysore and Indian Dairy Research Institute, Bangalore.
March, 1952] H. LAXMINARAYANA et al
15
After the samples were vigorously shaken to break the clumps of curd, small
quantities (approximately 1 gm.) were weighed into sterile flasks, diluted suitably
in saline and then plated in duplicate using milk agar. The plates were incubated
at 37°C. for 72 hours and the colonies counted. The arithmetic average of duplicate
plate counts was employed for calculation of total bacterial counts per gram of dahi.
Chemical analysis of the samples
Upon arrival at Bangalore, the samples of dahi were analysed for fat, ash, and
protein by. employing modifications of the procedures described in A.O.A.C. [1940].
Samples which were received in an unsatisfactory condition due to clumping of fat,
considerable whey separation, etc., as a result of the heavy joltings during transit,
were not used for analysis. Lactose was determined only in dahi samples collected
from places near about Bangalore and which had not been preserved with formalin.
Fat. Fifty grams of dahi were mixed well with 2 ml. of strong ammonia and
made up to 100 ml. with distilled water. Eleven ml. of the solution were taken
and fat determined by the Gerber method. The fat percentage of dahi was cal-
culated by multiplying the observed reading by two.
Ash. A 10 gm. portion of the sample was used for determination of the ash
by the usual procedure [A.O.A.C. 1940].
Protein. Total nitrogen was estimated by the usual Kjeldahl method, using
a 5 gm. sample of dahi, and the percentage of protein was calculated employing
6.3 as the conversion factor.
Lactose. Lactose was determined (according to Münsen Walker's gravimetric
method) only for a few samples collected locally and from places near about Banga-
lore. Due to the uncertainty of the age of the samples, and the long interval in
transit, extremely low values were obtained for the samples particularly in the
case of those obtained from distant places. Since such values of lactose were not
considered to be of practical significance, the determination of this constituent for
subsequent samples was discontinued.
Methods of manufacture and other particulars of the samples
Information regarding the history of the samples with special reference to the
type of milk used, process of manufacture, etc., was recorded wherever possible.
It was generally reported by those from whom the sample was collected that some
12 to 24 hours had elapsed since the addition of the starter to the milk. In the case
of a number of samples, particularly those obtained from south India, the high
degree of souring as well as yeasty smell shown by them indicated that the informa-
tion regarding age of the samples was not accurate and that they were mucholder.
There were considerable variations in the methods of manufacture, conditions
of storage and in the methods of marketing of dahi. Either cow's milk, buffalo's
milk, skimmed milk or mixtures of these were employed. Buffalo's milk was
commonly used where dahi was mainly utilised for ghee manufacture. In Bengal,
Bihar and eastern parts of Uttar Pradesh, cow's milk was almost always used for
dahi making. The milk was usually brought to a boil and allowed to cool to 37°
4 A
18
STUDIES ON DAHI : II—GENERAL SURVEY [Vol. XXII, Part I
TABLE II
Distribution of dahi samples (expressed as per cent) collected from different areas according to their
texture, flavour and microscopic appearance
Area
(Ref: Table-I)
Winter
Patna
Allahabad
Delhi
Karnal
Lahore
Hyderabad (Sind)
Nagpur
Ahmedabad
Poona
Hyderabad (Deccan)
Bangalore
Coimbatore
Madras
Bombay
Karachi
Calcutta
Dehra Dun
Mahabaleswar
Texture
Solid,
uni-
form,
smooth.
63
75
80
78
82
66
55
20
40
0
5
6
30
43
86
61
90
52
Summer
Patna
Allahabad
Delhi
Cuttcack
Poona
Bangalore
Madras
Bombay
Calcutta
60
72
91
0
40
20
10
54
13
Viscous
with
lumps
of
curd.
24
16
18
18
10
22
22
26
25
33
13
18
20
23
9
18
10
13
27
16
8
60
30
10
10
20
58
Watery
with-
curd
parti-
cles.
2
4
0
4
0
0
0
22
15
48
71
48
30
18
3
13
0
25
0
1
0
20
20
40
55
10
12
Pepto-
nized
or
gassy.
11
5
2
0
8
12
23
32
20
19
11
28
20
16
2
8
0
10
13
11
1
20
10
30
25
16
17
Aroma
Typi-
cal,
aro-
matic.
58
65
81
67
86
75
22
22
35
4
13
18
35
49
80
57
86
40
47
70
75
0
40
0
20
34
33
Aci-
dic.
24
25
13
15
12
24
45
40
30
90
72
84
25
28
16
22
3
26
40
23
18
100
50
80
55
25
42
Este-
ry of
alco-
holic.
2
7
1
7
0
0
8
0
0
4
5
0
5
10
2
0
0
20
0
0
3
0
10
0
10
6
11
Flat
or
un-
plea-
sant.
16
3 5
11
2
1
25
38
35
2
10
0
35
13
2
21
6
14
13
7
4
0
0
20
15
15
14
Taste
Sweet.
53
68
77
76
74
72
18
23
30
9
9
12
30
46
88
59
85
40
40
65
72
0
0
0
5
42
67
Mildly
sour.
31
24
20
17
26
18
45
32
40
18
23
30
35
2S
9
22
15
36
33
24
18
80
40
0
60
25
21
Very
sour
9
7
2
3
0
10
20
23
15
56
55
58
55
16
3
11
0
20
20
10
10
20
30
30
30
16
7
Bitter,
oily or
disag
reeable
7
1
1
4
0
0
17
22
15
17
11
0
20
10
0
8
0
4
7
1
0
0
30
20
15
17
5
appearance
Stre-
pto-
cocci
domi-
nant
46
60
75
72
84
60
18
8
0
0
3
0
0
37
84
74
75
20
20
42
46
0
0
0
0
17
21
Lacto-
bacilli
dom-
nant
18
7
0
8
6
20
28
40
0
68
69
66
90
28
3
11
8
40
40
34
26
100
60
90
90
68
23
Cocci
and
rods
equal
36
26
25
20
10
20
54
52
100
32
28
34
10
35
13
15
17
40
40
34
28
0
40
90
10
15
56
Yeasts
nume-
rous
30
19
26
24
26
25
46
50
80
56
82
90
87
82
15
18
10
27
40
50
48
100
80
80
70
85
76
March 1952]
H. LAXMINARAYANA et al
19
TABLE
III
Bacteriological and chemical analysis of dahi samples (figures in the table represent the ranges of variation
in the values)
area
(Ref : Table-I)
Bausalore
Coimbatore
Hyderabad (Dn.)
Poona
Madras
Calcutta
Bombay
Karachi
Patna
Allahabad
Delhi
Karnal
Lahore
Cuttack
(W)
(S)
(W)
(S)
(W)
(W)
(S)
(W)
(S)
(W)
(S)
(W)
(W)
(S)
(W)
(W)
(W)
(S)
Number
of
samples
38
25
17
12
9
20
20
10
47
39
30
22
17
29
36
17
22
5
Total bacterial
count per gm. of
dahi (millions)
88—672
100—560
226—456
*
*
15—438
*
*
*
*
18—730
21 6—406
*
*
13—22
*
319—560
99—262
Titratable acidity
(per cent lactic
acid)
0.30—1.39
0.49—0.94
0.70—1.78
*
*
0.60—1.70
1.32—1.95
*
0.38—1.44
1.64—2.15
1.12—1.72
1.09—1.31
*
1.15—1.42
1.12—1.45
*
1.38—2.00
1.05—1.18
Fat
(per cent)
0.14—2.20
0.30—6.90
0.80—4.80
*
0.84—4.0
0.10—1.03
0.20—0.30
2.40—4.80
2.80—7.40
2.90—9.10
2.10—8.20
*
1.20—4.40
1.40—8.40
5.10—9.00
6.40—8.60
3.30—5.50
2.80—4.60
Ash
(per cent)
0.22—0.76
0.26—0.69
0.44—0.72
0.38—0.50
0.48—0.51
0.42—0.96
0.34—0.57
0.58—0.85
0.44—0.85
0.47—0.70
0.47—0.69
*
*
0.49—0.85
0.46—0.68
0.48—0.70
0.37—0.66
0.59—0.78
Protein
(per cent)
1.29—4.43
1.39—3.26
2.28—4.54
3.00—3.60
3.46—3.91
2.18—3.20
2.28—3.27
4.03—4.97
2.60—4.10
2.94—4.10
3.54—4.77
3.96—5.15
*
3.74—5.17
3.58—5.39
3.87—5.16
3.63—4.80
3.15—4.83
Lactose
(per cent)
0.22—3.57
0.09—1.09
0.10—1.48
*
*
0.07—0.59
*
*
*
*
*
*
*
*
*
*
*
*
* Not determined
(W) Winter samples
(S) Summer samples
22 [STUDIES ON D AI—II GENERAL SURVEY Vol. XXII, Part I
near about Bangalore. With the exception of a few samples collected at Bangalore
and examined immediately, the values for others were generally below 1 per cent
and they did not also bear any uniform relationship with the corresponding titra-
table acidities of the samples. Although the decrease in lactose content may
be attributed to the continued fermentation of lactose by lactic acid bacteria, depend-
ing on the age of the samples at the time of testing, the effect of dilution with water
and formation of volatile acids from lactose by heterofermentative species, should
also to be taken into consideration.
The values for fat, ash and protein contents ranged from 0.1 to 9.1 per. cent,
from 0.22 to 0.85 per cent and from 1.29 to 5.15 per cent respectively. Since these
constituents of milk are not utilised to any appreciable extent by lactic acid bacteria,
the wide fluctuations in the values, particularly in the case of fat, are primarily
due to the initial quality of the raw material. All types of milk, cow, buffalo, mixed,
or skimmed milks as well as milk containing added water—are used in the manu-
facture of dahi. The fat and protein contents of dahi samples, in which yeasts
and moulds have been allowed to grow, would also be affected by the lipolytic and
proteolytic activities of these organisms. The high values of protein and ash shown
by a number of samples on the other hand may be partly due to the concentration
of milk by heating prior to addition of starter.
TABLE IV
Results of chemical analysis of typical dahi samples
Area
Bangalore (W)
Coimbatore (W)
Madras (W)
Calcutta (S)
Acidity
(per cent
lactic acid)
1.36
0.94
1.39
1.10
0.93
1.13
1.58
1.02
1.07
1.70
1.68
0.81
1.11
Fat
per cent
0.7
1.6
1.0
9.0
4.4
4.0
4.4
5.2
8.4
1.3
1.2
2.8
4.0
Protein
per cent
2.90
3.26
3.78
3.63
4.19
3.93
3.54
3.44
2.98
3.02
3.02
3.29
3.67
Ash
per cent
0.67
0.60
0.76
0.70
0.68
0.69
0.66
0.72
0.66
0.63
0.53
0.71
0.69
H. LAXMINARAYANA et
al
23
TABLE IV—contd.
Results of chemical analysis of typical dahi samples—contd.
Area
Bombay (W)
Bombay (S)
Allahabad (W)
Allahabad (S)
Delhi (W)
Delhi (S)
Karnal (W)
Cuttack (S)
Acidity
(per cent
lactic acid),
1.05
1.36
1.66
1.86
1.32
1.98
0.87
1.03
2.45
1.37
..
..
1.39
1.31
..
1.19
..
. .
1.49
1.39
..
..
1.50
1.09
1.08
Fat
per cent
44
5.6
3.2
6.2
84
5.0
64
6.8
6.8
74
4.6
5.0
14
44
4.8
6.6
84
54
4.6
6.0
..
6.4
8.6
2.8
3.6
4.6
Protein
per cent
3.99
3.82
4.05
4.19
4.06
4.75
4.56
3.85
4.62
4.56
443
3.92
3.92
4.14
4.51
3.67
3.99
4.24
4.32
4.55
3.90
3.87
3.74
3.35
3.85
3.15
Ash
per cent
0.64
0.73
0.64
0.68
0.68
0.63
0.67
0.63
0.70
0.71
0.67
0.71
0.66
0.68
0.63
0.59
0.63
0.68
0.61
0.73
0.60
0.70
0.70
0.67
0.70
0.63
(W) Winter. (S) Summer.
6
H. LAXMINARAYANA et
al
25
quality of milk and other factors in relation to the quality of dahi has been pointed
out.
ACKNOWLEDGMENTS
Thanks are due to the Indian Council of Agricultural Research for financing
this investigation and to the Director of Dairy Research for giving facilities for
carrying out the work at the Indian Dairy Research Institute, Bangalore. The
authors are grateful to Dr. K. K. Iya, Dairy Bacteriologist, for. his valuable sugges-
tions. The help received from the laboratories of provinces and States in connection
with the collection and examination of samples at various centres is gratefully
acknowledged.
REFERENCES
A. O. A. C. (1940). Official and Tentative Methods of Analysis, 5th Ed., A. O. A. C., Washington
D. C.
Davies, W. L. (1940). Indian Indigenous Milk products, Thaker Spink & Co., Calcutta
Joshi, N. V. and Ram Ayyar, C. S. (1936). Indian J. vet. Sci., 6, 141
Ministry of Health, England (1939). Memo, 139, Foods, H. M. S. O., London
STUDIES ON DAHI*
III. TAXONOMY OF THE LACTIC ACID BACTERIA OF DAHI
By H. LAXMINARAYANA, V. K. N. NAMBUDRIPAD, V. LAKSHMINARASIM,
S. N. ANANTARAMIAH, V. SREENIVASAMURTHY, AND K. K. IYA,
Indian Dairy Research Institute, Bangalore
(Received for publication on 8 January, 1951)
( WITH PLATES I—III)
A BRIEF review of literature on the microbiology of fermented milks including
dahi has been given in Part I of the present series of papers [Laxminarayana
and Iya, 1952]. There is, however, very little information regarding the organ-
isms associated with dahi and except for the isolation of a lactobacillus species—
Streptothrix dadhi [Chatterjee, 1910, and Ram Ayyar, 1928]—and two species of
streptococci, S. Lactis aromaticus [Joshi and Ram Ayyar, 1936] and S. diacetyl
aromaticus [Karnad, 1939]. No systematic study of this important subject has been
made. From a microscopic examination of dahi samples, collected from different
parts of India [cf. Part II, Laxminarayana et al., 1952] it was observed that South
Indian samples generally showed a predominance of lactobacilli while North Indian
varieties contained a greater proportion of streptococci. The types of lactobacilli
occurring in the latter samples also appeared to be mostly short rods in pairs, chains
or filamentous forms. The results of further studies carried out on the isolation,
characterization and taxonomical classification of the lactic acid organisms, found
in different samples of dahi, are reported in this paper.
The isolation of pure cultures of lactic acid bacteria from dahi or other material
does not present much difficulty because these organisms as a group are easily
distinguished from other bacteria by their morphology, cultural characteristics
and fermentation reactions [Davis, 1936; Orla Jensen, 1942; Breed, Murray and
Hitchens, 1948] and suitable methods, based on their nutritional and other require-
ments, are also now available for their cultivation [Orla Jensen 1942; Levine and
Schoenlein 1930; Davis, 1935a, 1939; Manual of Methods, 1944; Tanner, 1944].
The taxonomical classification of lactic acid organisms is, however, recognized
to be very complicated due to the overlapping of characteristics of different species
and variations encountered within the same species. In addition, there has also
been considerable confusion in the nomenclature of lactic acid bacteria adopted
by different workers. Orla Jensen [ 1919 and 1942 ], who was the first to make a
systematic study of lactic acid bacteria associated with dairy products, emphasised
mainly growth temperatures, nature of fermentation products and acid producing
* Investigations carried out under a research scheme financed by the Indian Council of Agri-
cultural Research, New Delhi.
27
6
March
1952]
H.
LAXMINARAYANA
et
al.
31
TABLE I (a)
Summary of characteristics used for the classification of lactic acid bacteria
STREPTOCOCCI
I.
II.
III.
IV
Name of
Species
S. thermophilus
S. bovis
S. lactis
S. cremoris
S. faecalis .
S. liquefaciens
S. durans .
S. dextranicum
(S. paracitrovo-
rus or S. kefir).
L.
citrovorum
(S. citrovoro-
us).
Growth
temperature
°C
10
0
0
+
+
+
+
+
+
+
45
+
+
0
0
+
+
+
0
0
50
+
0
0
0
±
±
+
0
0
Action on litmus milk
AC*
Ar or
AC
ARC
ARC
ARC
ARCP
AC
A or
AC (g)
a (g)
Maximum acidity in milk
(Percentage lactic acid)
1.00
0.60
0.95
0.70
0.80
0.95
..
0.27
0.90
slight
Volatile acidity in milk
0
0
0
0
0
±
0
+
+
CO
2
from glucose
0
0
0
0
0
0
0
+
+
NH
3
from arginine
0
0
+
0
+
+
+
0
0
Acetoin from citrate
0
0
0
0
+
+
+
0
0
Tolerance to methylene
blue
0
0
+
+
+
+
+
. .
. .
NaCl Tolerance
2 per
cent
0
+
+
+
+
+
+
. .
. .
4 per
cent
0
0
+
0
+
+
+
. .
. .
6.5 per
cent
0
0
0
0
+
+
+
. .
. .
pH
Tolerance
9.2
0
0
+
0
+
+
+
. .
. .
9.6
0
0
0
0
+
+
+
. .
. .
Fermenta-
tion of
Suc-
rose
+
+
±
0
+
+
0
+
0
Ma
tose
0
+
+
0
+
+
+
+
0
Heat
resistance ( 63°C. for
½ hour )
+
+
0
0
+
+
+
+
0
Remarks
Milk or lactose
media.
Grows slowly in
milk.
Mostly diplococci;
grows at 40°C ;
not inhibited by
0.3
per
cent
methylene blue.
Usually long chains
no growth
at
40°C. Inhibited
by 0.3 per cent
methylene blue.
Gelatine liquefied.
Many strains form
hemolytic coloni-
es.
Grows at 37°C.
very slow-growth
in milk; acetoin
produced in milk;
stimulated
by
yeast extract.
No growth at 37°C.
very slow growth
in milk. Acetoin
produced
in
milk; stimulated
by yeast extract.
*The order in which the letters are placed indicate the chronological sequence of changes.
A=»Acid; a =Slight acid ; C = Clot; R=Reduction of litmus; r = Slight reduction of litmus; P—Proteolysis of milk ; g = Gas production;
±=doubtful
or slight; o=Negative; + = Positive.
32 STUDIES ON DAHI: III. TAXONOMY OF THE LACTIC ACID, ETC. [Vol. XXII, Part I,
TABLE I (b)
Summary of characteristics used for the classification of lactic acid bacteria
LACTOBACILLI
Gr oup.
I.
II.
III.
Name of Specie
L bulgarieus .
L aucasicum .
L. lactis
L.
helveticus (L.
casei E).
L. acidophilus .
L. casei (L.casei L)
L. plantarum (L.
arabinosus).
L. breuis . .
L. ferment . .
Growth temperature
10
0
0
0
0
6
+
+
+
0
15
0
0
0
0
+
+
+
+
+
22
+
0
+
+
+
+
+
+
+
45
+
+
+
+
+
±
0
±
+
50
+
0
+
±
0
0
0
0
±
Action on litmus milk
AC*
AC
ARC
ARC
ARC
ARC
ARC
A or
AC
(g)
AR.
(g)
Time of curdling milk
24
24
24-48
24-72
24-72
2-6
days
7-14
days
15-30
days
OC
Maximum acidity in milk
(percentage of lactic acid)
>2.0
>2.0
1.4-1.8
>2.0
>2.0
1.4-1.8
1.4-1.8
<1.0
<1.0
Volatile acidity + CO
2
in milk
0
0
0
0
Traces
0
Sli-
ght
High
High
Growth in 2 per cent
lactate media
0
0
0
0
0
±
0
+
+
Tolerance to methylene
blue (0.1
per cent)
+
0
0
+
+
0
..
0
..
NaCl
tolerance
2.5 per
cent
0
.
+
+
+
+
+
+
+
5 per
cent
0
.
0
0
0
+
+
+
+
Fermentation
of
Suc-
rose
+
+
+
0
+
+
+
+
+
Mal-
tose
0
+
+
+
+
+
+
+
+
Heat resistance 63°C. for
½ hour
+
+
+
+
+
0
±
+
+
Remarks
Inhibited
by 0.5
per cent bile salt.
Best growth with
yeast.
––
––
Not inhibited by
0.5 per cent bile
salt.
Prefers lactose to
Maltose.
Stimulated
by
yeast;
prefers
maltose to lactos.
Marked stimulation
by yeast extract;
marked fermen-
tation of pentose
(arabinose).
Stimulated by yeast
extract; weak or
no fermentatiom
of pentoses.
*The order in which the letters are placed indicate the chronological sequence of changes.
+ =Positive ; ± = variable or a few strains positive ; 0 = Negative : A = Acid ; C = Coagulation; P = Proteolisis of curd ; R=Reduction of litmus before clot ;
g=May show gas formation ; a=slight acid ; r =slight reduction.