174
ABSTRACTS
The microflora of this form of silage consisted mostly of lactic acid bacteria—lacto¬
bacilli, streptococci, micrococci and sarcinae, together with yeast and yeast-like orga-
nisms. In the lactobacilli homo- and heterofermentative types were represented, e.g.
Lactobacillus plantarum in the former and L. brevis in the latter group.
The homofermentative streptococcal types belonged to the Streptococcus lactis
group and the heterofermentative forms were identified as Leuconostoc mesenteroides.
The types of micrococci and sarcinae isolated were not identified but were shown to
possess characteristics not usually associated with these types of organisms, namely the
formation of high concentrations of lactic acid and some carbon dioxide.
Freshly ensiled fodder contained motile lactobacilli, streptococci and micrococci
but the majority of the lactobacilli and sarcinae were associated with older samples
(cf., the microflora of cheese at different stages of ripening).
The characteristics which proved to be valuable for the differentiation of the orga-
nisms were ability to produce carbon dioxide, amount of lactic acid formed and the ratio
of lactic to acetic acid.
[W. L. D.]
Passage of carotenoids from food to milk in the cow. The fate of lycopene.
A. E. GILLAM AND S. K. KON. (1940). J. Dairy Res. 11, 266.
I N order to find out whether the tomato pigment, lycopene, an isomer of carotene, can
pass from the food into the milk of the cow, three different cows were fed with 1,500 g.
of tomato purée daily (in four fractions) and the resulting milk fats were examined for
lycopene. When the fats were submitted to examination by careful chromatographic
adsorption, no evidence of the presence of the pigment in the unsaponifiable matter of
the butterfats was detected.
It was concluded that although the cow normally absorbs α-and-β carotene and
certain oxidation products of these substances from its food, it completely excludes the
isomeric and very similar lycopene which was found in considerable quantities in the
faeces after tomato feeding.
The examination of the carotenoids of several colostrum fats also provided no
evidence of the presence of lycopene.
[W. L. D.]
Subclinical staphylococcus mastitis in herds free from streptococcus mastitis,
and its effect upon milk composition. P. M. F. SHATTOCK AND E. C. V.
MATTICK. (1940). J. Dairy Res. 11, 311.
I N the milk of herds free from streptococcal udder infection, changes in chemical com
position and the pH of the milk have been found to accompany the presence of
staphylococci.
In schemes for the control of mastitis in dairy herds based on the detection of Str.
agalactiae in the milk, cases of infection by staphylococci are missed because their growth
is suppressed on Edwards' crystal violet blood agar. It is known that clinical cases of
staphylococcus mastitis causing serious disturbances in milk yield and composition are
rare ; the subclinical type may however be present to a considerable extent and remain
unsuspected.
The present work shows that in cows free from streptococcus mastitis (428 samples)
staphylococci were present in 21 per cent of the cases and no clinical case was observed
even with careful recording of all abnormalities of milk and udder. The changes in milk
composition due to this form of infection are similar to those occurring in cases of strep
tococcus mastitis, namely, a lowering of the ' casein number ' below 78 and a rise in pH
above 6.6. In 39 analyses, 10 samples with counts of Staph. aureus of from 150 to over
2,000 per ml. had a pH of 6.80-6.95 and a casein number of 68-77, the changes being
greatest in samples with high counts.
It was established that changes in milk composition occur with staphylococcus in
fection but no evidence was available that such changes affected the behaviour of milk
in the manufacture of products.
[W. L. D.]