The Portland daily press., 1878-07-25
AGRICULTURAL.


AHhtA anu FFeBtTtatl0n.
An English paper some time ago colaed
all the chemical facts in relation to milk, its
adulteration and preservation, from which we
exlracl the following paragraphs of interest:
COWS milk, of average quality, contains
from IO 10 II per cent of solid matter when
evaporated to dryness by steam heat, and has
mean sp. gr. of 1.030, while that of the skim
med milk is about 1.035; and of the cream,
1.0244 (Ure.) The average cream of cows
milk contains As per cent of butter, 3.5 per
cent. of curd, and 92 per cent. of whey. (Ber-
zelius.) The skinned milk consists of water,
e2. per cent. curd, 2.S per cent. ;sugar OF
milk 3. 8 per cent. Tactic acid lactate of potas-
sa, and trace of laetate of iron, 6 per cent. !;
chloride of potassium, phosphate of potassa,
and rthy phosphates (lime), 2 per cent,
tBerzelius.) Perfectly fresh milk is slightly
alkaline, but soon becomes acid on exposure
to the air, and after time white coagula of
casein lcurds) separate from it. This change
is Immediately effected by the addition of rem
net or an acid. That from the first, when
dried and pressed, constitutes cheese.
The common frauds practised by milk-deal-
ers are the addition of water and the subtrac-
tion of part of the cream. Sometimes potato
starch is added to the milk, to give it a creamy
or rich appearance, and this addition is still
more frequently made to increase its consist
ence and quantity. The presence of potato
starch may be determined by boiling some of
the milk with little vinegar, and after sepa-
rating the coagula by strainer and allowing
the liquid TO become cold, testing 1t with So
luton or tincture of iodine. If it turns blue,
starch, Hour, or some other amylacioEs sub
stahce, has been used to adulterate it. In
most cases it will be sufficient to apply the
test to the unprepared suspected milk. 1t
has frequently been stated that chalk, plaster
OF Paris, gum, gelatine, flour, sugar, muciage
of hemp seed, the brains of animals, and 9TH
er similar substances, are often added to LON
don milk, but there is no reason to suppose
there is truth in these assertions, as some of
these articles are too costly to be used, and
the presence of others would so alter the fla
vor or appearance of the milk, or would SO
soon exhibit themselves by subsidence, as to
lead to their detection.
Milk may be preserved in stout bottles, well
corked and wired down, by heating them, in
this state, to the boiling point, in water
bath, by which means the oxygen of the small
quantity of enclosed air becomes absorbed.
1t must afterwards be stored in cool situa-
tion. By this method, which is also extern
.ively adopted for the preservation of green
fruits, vegetables, &C., milk will retain its
properties uualtered for years. A few grains
OF carbonate of magnesia, or, still better, of
bicarbonate of potassa or soda, may be advan-
tageously dissolved in each bottle before cork
ing 1t. Under Bettels patent, the milk OF
cream is scalded, and, when cold, strongly
charged with carbonic acid gas, by means of
asoda-water machine, and the corks are wired
down in the usual manner. The bottles
should be kept inverted in a cool place.
An excellent method of preventing milk
from turning sour, or coagulating, is to add
to every pint of it about ten or twelve grains
OF carbonate or bicarbonate of soda. Milk
thus prepared may be kept from eight to ten
days in temperate weather. This addition is
harmless, and, indeed, is advantageous to dys-
peptic patients. According to D'Arcot,
1-2OOOth part of the bicarbonate is sufficient
for the purpose. An excess of alkali used in
this manner may be detected by the milk
turning tumeric paper brown, even after it
has been kept some hours, and by the ash OBJ
tanned by evaporating little to dryness, and
then heating it to dull redness, effervescing
with an acid.
Mtk P0Dder.-1. Fresh skinned milk, 1
gallon; carbonate of soda lin very fine pow
der), Ii dr.; mix, evaporate to one-third by
the heat OF steam or a water bath, with con-
slant agitation; then add of powdered white
sugar, 81 lbs, and complete the evaporation
at reduced temperature; reduce the dry
mass to powder, add the cream well drained,
which was taken from the milk, aud after a
snoiouSu dumlALuTe put Tue WuOlo luLO well
stoppered bottles or tins, which must be at
once hermetically sealed.
2. Carbonate of soda, 1dr.; water, Il fl. o. !;
dissolve, add of fresh milk, quart; sugar, 1
lb.; reduce it by heat to the consistenee of a
syrup and finish the evaporation on plates by
exposure in an oven.
About an ounce of the powder agitated
with pint of water forms an agreeable and
nutritious drink, and good substitute for
milk at sea. 1t may also be used for tea or
coffee in the solid form. This pIocess, which
is very old, has been recently patented.