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Патент USA US2119616

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Patented June 7, ‘1938
2,119,616 '
rnocass or ms'ranmzmo MILK
Rolan Jay, Wightman, Little Falls. N. Y; assigno'r' ,
to Cherry-Barrel! Corporation, Wilmington
Del., a corporation of. Delaware
No Drawing. Application April 1, 1936,
Serial No. 72,111
‘4 Claims. _(o1. 99-212)
This 'invention relates 'to improvements in
‘novel process ofipasteurizatmn giving improved
methods of pasteurization. While the improved
results over previous processes; also to improve
short time pasteurization methods so as to ma
terially reduce the bacterial counts ‘in the-pas
methods of thisapplication are particularly de
sirable for pasteurizing milk and are .herein
5 after described as so employed, the invention is
not limited to the pasteurization of milk, but is
teurized products; also to iniprove shorttime milk 5
pasteurizing'methods in a way that will not im
" also adapted for pasteurizing other substances, ' pair the cream layer or volume or the ?avor of the
such for example as cream, milk compounds,
and vegetable and fruit juices.
Milk is commonly pasteurized by heating it to
and» holding it at a ‘prescribed ‘temperature for
a period of time, the length of which usually de
pends upon the pasteurizing temperature to which
milk; also to provide an expeditious, and e?lcient
method of pasteurizing milk vwhich will improve
the cream vlayer and’ give a lower bacterial count
than previous short time pasteurization methods; I
and also to provide a -method of pasteurizing
milk which willinsure satisfactory results as to
the milk is heated, and then cooling the milk to a ' bacterial reduction, cream layer and ?avor in th
.15, temperature suitable for bottling or‘ storing it.
For example, in long time milk pasteurizing Proc
esses that have been used extensively, the-milk
_ is heated to about 145° F. and held at that tem
- perature for about thirty minutes before cooling
0 it, while in the more recent so-called short time
2 pasteurization processes'the milk is heated to a
pasteurized milk.
According‘ to my improved pasteurization meth
ods, the milk, as heretofore, is’ heated to and held
at a suitable temperature for the appropriate pe
riod of time, but prior or preliminarily. to this -
heating and holding treatment the mi1kvis\sub-_ 20
jected to shock or relatively sudden changes in
higher temperature, such as ‘about 160° F., r at
temperature one or more times, after which said
which temperature it is held for a relatively short
heating and holding treatment is carried out. For
Period of about ?fteen ‘seconds.
example, the milk may be ?rst heated from a
cold condition to a predetermined temperature 25
In both the
long and short time processes as heretofore com
25 monly practiced, the raw milk has been heated to
not lower than about 150° F. and not above about '
the required pasteurizing~ or holding tempera-.1 160° F. (said heated temperature being preferably
from 155° to 158° F. inclusive), and then cooled
'ture by a heating operation which‘is uninter
rupted by any cooling or lowering of the tem
down to a temperature of about 145° F. or less,
following which preliminaryheatingand cooling
30 peratureof the milk. Short time pasteurization,
in addition to the saving of time it eifects, is con .the milk is again heated to a temperature of
sidered advantageous over long time‘ processes about 160° F. and is held approximately at that because the milk is in contact with the equipment temperature for the required short time, at least
for a much shorter time, with the result, that about ?fteen seconds. It is then cooled to 40° F.
the milk has less chance for picking up metallic or other temperature suitable for bottling or 85
or “o ” ?avors. Experience with short time pas- '
teurization processes indicates that the ?avor of
the milk is improved bythe short time methods,
it being believed that the enzymes have not'been
40 affected, and that the‘ ?nal pasteurized product'
has more nearly the ?avor of‘ fresh, sweet, raw
Not infrequently, however, short time milk pas
te'urizingmethods, as practiced at present, are
45 unsatisfactory on account of obiectionably high
bacterialvcountsin the pasteurized milk. .The
:lther usual operations which succeed pasteuriza
f The ?rst or preliminary heating
apparently lowers the resistance of
to a point such that the following
short time treatment is adequate to
and cooling
the bacteria
heatingv and
kill the bac
Nevertheless said preliminary heating‘ is , '
vsuch that its action in- conjunction with the
?nal heating and holding does not impair the
cream layeror volume or the ?avor of the milk 45
any more than is done in ordinary short time pas
‘f longtime and short .tim'eholding syster'nsJf both I ,teuiization. On _‘ the "c0nt1'ary;'improvements_ ‘in
are operated properly, show very little diiference the cream layerfas well‘asfgreatly reduced bac
‘in cream layer or volume. Normally there should terial counts have been obtained in pasteurizlng
milk by the hereindescribed methods.
50 be very little difference shown in bacterial reduc
In the preliminary heating of the raw milk, if
tion, especially in bacteria of pathogenic type, al
though it'has been noticed that a heat-resisting its temperature is muchvbelow. ,100° F., it is
' type of bacteria has been more prevalent in the heated up to about 100° F. and may be then
short time systems thaninthelong time
. raised from that point to'the before mentioned
55 The objects of my invention are to provide a predetermined temperature between 150 and 100
.degrees F. m a‘ period of time which may vary
from approximately two seconds to four min
thencooied‘down to 145° 1". or lessin tromtw'o
utes. The time taken ior heating the raw milk heated to 155°to 158' and recooled to 145° or
up to the 100° point is not believed to be especially vlcssinaboutthesameperiodsoi' timeasusedior
important and may vary from a' few seconds to theiirstheatingand coolinggbei'ore ?nallyheat
one-half hour more or less,‘ but it is considered
ing the milk to and holding it at approximately
that the time for‘ heating the milk from about
160°-ior a minimum of about ?fteen seconds.
100° to the temperature between 150 and 160
degrees should be kept within about the limits
liminary high temperature to approximately 145°
or less may be eiiected in a period of time varying
from about one second to one minute more or less,
15 and the time for again heating the milk to the
I claim as my invention:
1. The hereindescribed short time method oi’
pasteurizing milk which comprises raising the
temperature oi, the milk to about 100° F. and _
preliminarily heating the milk from that tem
perature to a temperature oi’ approximately 100°
1".inaperiodoitimenotexceedingtourminutes. ‘i
then promptly cooling the milk bei'ore pasteuriza 16
?nal minimum temperature of‘ about 160"‘, at , tion thereof occurs at least to approximately 145°
which it is held for the'minimum period of about ‘F. in a period oi! time not exceeding about one
- ?fteen seconch, may be from about two seconds
to two minutes more or less, depending upon the.
particular type oi.’ equipment used and the length
of time required for the milk to ?ow over or
I through it. The time for the ?nal cooling of the
milk to bottling or storing temperature may vary
over. a considerable range. such as from about
pasteurizing milk which comprises preliminarily
two seconds to four minutes more or less.
heating the milk to a temperature between 155°
F. and ‘160° R, such portion of said heating which
raises the temperature oi'the milk over and
above 100° 1". being accomplished ina period of
time not exceeding four minutes, then cooling
the milk at least to approximately 145° 1'. within
a period of time not exceeding one and one-half
minutes from‘ the time the milk attained said
Good results have been obtained in practice
by carrying out the method with the‘ following
temperature and time schedule:
_The/ raw milk at a temperature of approxi
30 mately 40° 1''. is raised to around 100° F. in ap
proximately two minutes and further heated
trom that point to 158’ I". as near as possible
in about one minute, then‘ promptly cooled down
to‘ 145° F. in approximately one minute, then
minute, then heating the milk to a temperature of -
approximately 160° F. in a period 0! time not
exceeding about two minutes and holding it
approximately at 160° 1''. for approximately ?l
teen seconds, and then cooling the milk.
2. The hereindescribed short time method of
preliminary heated temperature, then heating the
heated from this temperature to approximately
160° F. in about one‘ and one-half minutes and
milk to a ?nal high‘ temperature or about. 100°
F. in a period of time not exceeding about two
minutes, and holding it approximately at said
held at that ' temperature for approximately
a last mentioned temperature for a period of time
?fteen seconds, and ?nally cooled to' about 38°‘ of approximately ?fteen seconds, and then cool
F. in about three seconds. This procedure re
40 duced the bacterial count more ‘thanthirty-?ve
percent overv previous ordinary short time
pasteurization with the same apparatus and the
cream layer was also improved.
between the preheating and precooling stages.
Thatis, themilkmaybeheld atits preheated
temperature around 155° to 158° for ashort time
cording to. the ‘preheated temperature med.
periodm betweentheprehea?ngandpreoooling
preliminarilyheated and cooled only once. but
ther reduction of baeteriaiis desired. mui?ple
the ?nal heatingandholding process, maybe
employed. Ibrex'ample,therawmiikatamd
76 tromtwosecondstotwo minutes moreorlel.
ing the milk.
_3. The hereindescribed ‘short time method oi
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