Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1916-02-04


properly performed and that the process
makes safer even the most carefully
handled and inspected milk, is the con-
clusion of a new professional paper Of the
Department Of Agriculture. in which are
set forth the most recent conclusions OF
scientists in regard to this matter. 1t
seems probable, says this paer, that with
in the next two years large proportion
of the milk supply in the large cities will
be pasteurized. There is already a
marked tendency in this direction. About
| 10 years ago only per cent of the milk
supply of New York City was pasteur-
lied. In 1914 IS per cent. was treated in
this way At the present time 50 per
cent of the milk supply of Boston is
pasteurized, and there are corresponding
increases in many of the smaller cities.
Before the value of pasteurization as a
hygienic measure was as we'll recognized
as it is today. it was pFacticed in secret
! by a number of milk dealers as means
! of preserving milk and preventing 1t
from souring. Its commercial value in
| this respect is undoubtedly great. but its
chief function is the destruction of dis
! ease producing organisms. Proper pas
! teurization should destroy about 80 per
cent. of all the bacteria in the milk, al
though when the bacterial count of the
raw milk is low the reduction may be
somewhat smaller. The efficiency of tn.
hn
| based on the per cent, but rather on the
character of the bacteria destroyed.
The kinds of bacteria that remain alive
| after pasteurization depend on the tenn
perature to which the milk is heated and
the species of bacteria which are in the
raw milk. Three processes Of pasteuriza-
ton, known respectively as the flash
process, the holder process, and pasteur-
zation in the bottle, are now practiced
in this country. In the flash process the
milk is raised quickly to temperature
of about 1862 F. or more, held there for
from 30 seconds to a minute, and then
cooled quickly In the holder process the
milk is heated to a temperature of from
l409 to 100 F. and held there for half an
hour When pasteurzation in bottles is
Ties with water-tight seal caps, which
are immersed in hot water and held for
from 20 to 80 minutes at temperature OF
40 F. In this way the pasteurized milk
is not subjected to any danger of rein
lection. ON the other hand. the seal caps
| must be absolutely tight and this In
wolves increased cost. In general. il
may be said that the holder process is
coming into greater favor than either OF
the others. This process permits of the
use of lower temperatures which, foi
various reasons is highly desirable. An
other method of pasteurization, or rather
a modification of the present holder pro
cess, suggested by the Department inves
tigators, is that of bottling hot pasteur
lied milk The process consists in pas
teurizing milk by the hblder process a
145o F. for 80 minutes. then bottling i
while hot in hot bottles steamed for tw'
minutes Immediately before filling. Afte
filing the bottles are capped and may b.
cooled by any of the systems in whicl
the caps are protected. The bottles ar
sprayed with water or cooled by forced
, air circulation.
When milk is held at 1852 F. for 80 min
, utes, all the dsease-producing bacteria
so far as can be ascertained. are com
pletely destroyed. At the same time
larger percentage Of the bacteria tina
cause milk to sour and a smaller per
, centage of those that cause it to rot ar
left than when higher temperature i
employed. Pasteurzed at low temper
allure, milk undergoes no change which
affects its nutritive value or its digesti
bility. Subsection to a temperature o
1902 F. or more, however, does result Il
certain chemical-changes. Finally, pas
teurization at low temperatures is NOR
economical because the expense of heat
ing and cooling is less
This. of course, does not mean that IN
sufficient pasteurization should ever b.
; tolerated AS a matter of fact, the pro
cess of pasteurization is frequently per
formed improperly. For the holder pro
; cess. 14o' F. is the point at which inves
LEGATIONS have shown that disease-pro
ducing bacteria are killed, but In prac
tice it is advisable to use Temperature
several degrees above this minimum
/ safety. When the flash process Is used
investigation has shown that very man!
dealers fail to heat the milk to suffi
GENTLY high temperature. This appear
to be another argument for the use o
the holder process. although conditions
in this respect are said to have beer
improved greatly in recent years.
, Another common defect in the process
of pasteuri:ation is carelessness in tn
handling of the milk after it has beel
treated. As has been said already. thi
is one reason why pasteurization in bot
ties is advocated. One false step ii
handling the milk after it has been pas
tuerized will undo all the good effects o
the process. The milk should be coole
as rapidly as possible to about 40 F. an
! kept at that temperature until delivered
J If this is done. there is only a slight bac
{ tsrial increase during the first "a hours
, 1t has been held by some investigator
, that bacteria grow faster in pasteurize
, milk than in raw milk. This point, how
ever, has never been thoroughly estab
lished and other Investigations ihdicat
that the rate Of increase is approximate
ly the same.
Another objection that has been raise
to paSteuriZed milk is that the bacteri