DE1692220A1 - Method and device for the sterilization of liquid food - Google Patents

Description

PATENT LAWYERS

DR. ING. A. VAN DERWERTH DR. FRANZ LEDERER

HAMBURG-HARBURG 8 MUNICH 8. WILSTORFEH STR. St. -TEL. (04111 77OB6I LUCILE-ORAHN-STH. 22 - TEL. (08Ml 44 08

Munich »7 * December La / e

1 ^ 2220

Applicant: Unilever N.V., Museumpark 1, Rotterdam Netherlands

Method and device for the sterilization of liquid food.

The invention relates to the sterilization of liquid food.

Food can be sterilized by heat treatment »if it is exposed to high temperatures for long periods of time from, SO ^ however this can lead to chemical changes in the Food lead »thereby becoming undesirable organoleptic Changes result, for example in terms of consistency, smell, taste and the color. If a liquid food comes into contact with a solid surface at high temperatures is »there can still be unwanted solid deposits build up on the solid surface ·

In the present case, "sterilization" is understood to mean the reduction in the number of contaminating microorganisms to such an extent that the product exposed to sterilization does not show any noticeable signs of damage after prolonged storage at ambient temperatures

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has microbiological contamination.

Are under "liquid ** or" flowable "food here not only solutions but also suspensions, dispersions or suspensions of solid substances in one Understood liquid, such as Milk, cream, or soups Fruit or tomato juices that contain solids such as. »Minorized Pleieoh, Gertie« or fruit solid · contain.

It has been found that it is möglioh to sterilize a liquid food in that it forms a carried by no solid surface current flowing from the liquid food, that this current for sufficient for sterilization of the food period of time to a temperature of at least 10O ⁰ C is heated while held out of contact with a solid surface, and that the stream of liquid food is then cooled below a temperature at which appreciable thermo-chemical changes can take place while it is kept out of contact with a solid surface. Cooling is "preferably" effected by mixing the heated liquid food with a cool sterile stream of the same food. This method ensures that food is kept out of contact with any solid surfaces for the * entire time * it is at elevated temperatures, since such contact would generally result in part of the food being left on the for a long time would be held at a high temperature, which would result in disruptive thermocbemical changes and what would also result in the build-up of a solid deposit of the liquid food on the featen

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Surface would result. These disadvantages are caused by the The method according to the invention overcome in that the liquid in the heated state does not come into contact with any a solid surface.

Through the inventive & D process at a temperature of at least 15O ⁰ C for Bruohteil a second treated milk is sterilized while organoleptisoh the essence of untreated milk indistinguishable remains · oranges "* and similar fruit juices can be sterilized in the same way by the treatment at temperatures between 100 ⁰ O and 150 ⁰ C. The period of time during which the liquid is at elevated temperatures is preferably not greater than one second.

The unsupported stream can suitably thereby be formed that you can the liquid food from a container through an opening in the bottom läohe des Can pass through the container or through a mouth, which is caused by the end of a tube connected to it. forms is. To ensure even heating and the maintenance of flow stability, is the mouth through which the liquid flows out, preferably directed substantially vertically downwards, although one directed at an angle to the vertical and formed stream can also be treated according to the invention

In »a preferred embodiment of the finding the -? tr, om heated by microwave radiation, which for example, a frequency between 300 and 10,000 MHz,

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ο » Α. mm

preferably between 800 and 3,000 MHz. These Radiation which can be obtained from an oscillator such as a magnetron will prove advantageous through a waveguide to the liquid column, where the transverse dimensions of the waveguide for best mode of action of the frequency of the radiation are adapted, which feature is known in the microwave oven is.

"Bs has been found, therefore, it is a suitable method dad m for heating the liquid flow is, it duroh to pass a waveguide, it aοdaß along the waveguide transmitted energy absorbed ·

A particularly suitable arrangement is the one used To transmit radiation to the material carried in the flow of liquid consists of the flow vertically duroh the Central region of a horizontally arranged waveguide, the current being essentially parallel sum applied electric field runs «.

When two or more streams traverse a single waveguide to produce an essentially equal and equal » P ensure moderate heating, the currents should along suitably arranged tracks through the waveguide are guided, for example at equal distances from the middle region of the waveguide. You exact arrangement of the « Current or currents within the waveguide to the point of best and even heating However, it can be easily deduced from knowledge of Hatur and behavior of a microwave oven on the line along a waveguide.

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The temperature to which the food is heated "is preferably between 18O ⁰ C and 22O ⁰ C and the time period, the" exposure time ", during which the temperature is maintained" is preferably zwisohen 0.40 and 0.10 lake. The temperature and length of time of heating will of course depend on the liquid material being treated, however for milk the heating has been to a temperature of about 190 ^° C. to 200 ^° C. for approximately 0.15 seconds. found to be sufficient for the sterilization of the milobus without any noticeable changes in appearance, color or structure being brought about.

Wax heating during the desired time the Heibe liquid should be cooled quickly to take advantage of the invention ensure "that in part on a uniform short Sterilisatlonszeit based. Therefore, if a material such as milk "is not rapidly cooled after heating to the desired temperature for a required period of time", changes in taste, color, and texture can occur as a result of the time being exceeded at high temperature.

The heated stream of liquid food is preferably passed through the without contact with a solid surface rapid admixture of a portion of the same liquid life, which was cooled prior to admixture with the heated column of liquid.

The heated stream of liquid can therefore conveniently and quickly be cooled by placing one or more jets of the previously cooled liquid at one point on it Bahn directs "which follows after leaving the Berelohss" in which noise is supplied, eodafl through the so

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reached confluence causes rapid cooling will.

A particularly suitable arrangement is to direct a series of jets of the previously cooled liquid inward within the tub area so that they collide with each other and with the heated liquid stream to form a cooled by their confluence To form mixture.

Another effective method for cooling the heated liquid sstromee is _t this liquid flow in a container, for example in the form of a funnel, to direct, in welohem a substantially constant level Taeb maintain the precooled and previously treated liquid * l * 3s is of course to It is important to maintain sufficiently rapid cooling to ensure that the chilled liquid flows into and out of the container in sufficient proportions to prevent any substantial increase in temperature of the mixed liquids which could deleteriously affect the proportions of the liquid food being treated.

When heating liquids to temperatures above their ·>. At the boiling point, it is necessary to let a Uberantmosphlrisonen Druok act on the column of liquid in order to prevent the liquids from boiling, which could lead to an unstable flow and uneven heating. For this purpose, a gas pressure of preferably U to 21 kg / om ^{2 is maintained} in the area of the unsettled liquid column, although a pressure higher than 21 kg / om? if erwünaohi can be used.

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Anything can be used to create a “superatmospheric pressure” suitable Gae are used. " ea threw however eauerat offfreier 3 ticket off ale particularly suitable found » when liquids like β, Β. Milk to be treated, which otherwise tend to undergo oxidative changes, if they are treated in the presence of air or oxygen

In order to have a stable inadmissible flow of liquid constant flow rate in such a below To maintain the system under pressure »it is necessary to bring the fluid to a higher pressure than it is maintained within the 3thrombereiob.es, before the liquid passes through the flow-forming opening. Am suitable method for the liquid under Druok su setseni consists in “taking them out of a storage container to the flow-forming opening su) and any irregularity in the flow velocity can advantageously be vaporized by means of a pressure control by a hydraulic piston accumulator · in particular At this stage it is important that there be no Gfas in the liquid is dissolved or dispersed prior to the formation of the current »as the subsequent heating expels this Sas and such a flow can cause instability · Sin hydraulic accumulator with a piston »allowing the access of a pressurized gas from the pressure * treated liquid prevents this risk.

In a further embodiment of the invention, the The flow of liquid can be heated «because it can be used an alternating electric current «The electric Alternating current can be supplied in suitable catfish via electrodes

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be applied to the stream, welohe in the liquid container from which the stream is also formed and arranged at the point of the confluence of the pre-cooled and gate-treated liquid at the end point of the flow, whereby the alternating current is caused, length of the fluid atromea to flow and this ao to be heated to the desired temperature on the 2, uaamaenflu8 ssu dem dea Plüesigkeitastroaee should in each case be sufficient to ensure that the Liquid is heated in the stream area and not to a greater extent in the container or at the confluence. While The supply of the alternating current means that the liquid is continuously heated from the point onwards which the flow of liquid is formed up to the point at which the flow of liquid ends «

The frequency of the supplied alternating current should be sufficient to prevent deteriorating changes in the To prevent liquid due to electrolytic effects. Advantageously, if the network frequency is im generally 30 to 60 Hs can be used without modification, although ea generally required let »the tension to increase such a power source in order to obtain the desired heating.

AIa example for. In this embodiment of the invention, a 4.3 cm long Miloha column was heated by an alternating current of 50 Hz, the supplied power being 2.8 kW at a current of 700 mA "The length of the liquid column, the frequency of the current" and the Expended work can of course be changed «, xm

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to meet the specific requirements »the However, values of these variable quantities can easily be determined on the basis of general knowledge »

Its a suitable device to carry out the prepared described method according to the invention in view to the preferred embodiment includes means for Formation of a stable, unsupported column of the liquid Foodstuffs »heating means» which are suitable for connection to an energy source »which are arranged in such a way that they enable heating in the path of the column of liquid and coolant to provide cooling at the end of the path through which the column of liquid thus heated by mixing the heated column of liquid with a cool * sterile stream of liquid food ~ to enable. ^

In order to ensure that the heated liquid stream remains at or near its maximum temperature for a sufficient period of time when the device is in operation, it may be desirable that the heating means and the cooling means are spatially separated in order to create a zone of action between them .

The means for forming the liquid column is preferably one in the lower wall of the one to be treated Liquid-containing container attached discharge opening or a tube »which has an outflow opening connected to it.

To maintain a stable column of liquid and a To ensure smooth heating of the liquid in the column, preferably let the orifice substantially

vertically downwards

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TM To ensure that the heat treatment of the column is uniform, it is important that the flow rate of the liquid is constant. This can can advantageously be achieved by damping changes in the flow, for example by means of a hydraulic accumulator which is arranged in the feed system.

The energy source can be microwave radiation, which is generated, for example, by an oscillator, e.g. a magnetron, and the heating means then advantageously comprise a waveguide. she Cross-sectional measurements of the waveguide should be adapted to the frequency of the radiation and since this is in the Microwave technology is well known, it does not require a further and more detailed description.

Furthermore, in the interests of optimal operation, the path of the liquid column should preferably pass through guide the central region of the waveguide.

In a preferred embodiment of the device the rectangular waveguide is arranged horizontally and the path of the liquid column is arranged so that it leads in the vertical direction through the center of the waveguide torquer sennit ta, with the electric field resulting from the microwave radiation at its Application is parallel to the path of the liquid column.

The waveguide can also be provided with means for example with pistons and / or adjustable or fixed Stiohleitungen within the waveguide to the Adjust radiation so that the optimal adaptation of the

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Radiation to the load can be achieved through the column can "when the device is in operation"

The coolant includes a device to provide a rapid Ensure mixing of the heated liquid column with cool sterile liquid. A useful form A cooling device is a pipe or a series of pipes which run along the path of the heated liquid » Keitssäule are arranged, with the open ends of the tubes are directed so that the cooled liquid in the form of rays can be directed against each other in order to strike the heated column of liquid and so through their influence to bring about rapid cooling of the heated liquid. Am «another form of coolant is a vessel, for example an upturned cone * which has one or more inserts for the Entry of the cooled liquid and is provided with at least one outlet, which is below these inlets Is arranged, through which the cooled liquid together with that originating from the liquid column Liquid can pass through to bind to another To get the vessel or container for storage or to Cooling and return to the coolant *

When liquids are at temperatures above their boiling point are treated, it is necessary in the vicinity of the liquid column a Üheratmosphärisohen gas pressure maintain. For this purpose, the means forming the liquid column, the heating means, the coolants and, if present, the zone of action between the heating and coolants in suitable catfish to be included together around the Ingress of air on an atmospheric bridge

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su prevent and should have means of recruitment and maintaining an appropriate superatmospheric

Pressure inside this "enclosure".

According to a further embodiment comprises suitable apparatus for carrying out the above described Method according to the invention an electrode system which is suitable for applying an electrical to the column of liquid To transmit alternating current when the device is in Activity is located. In a suitable manner, at least one electrode, for example a carbon electrode, in the container for the untreated liquid be arranged near the mouth forming the liquid column, and at least one more at the mouth of the bin pre-cooled, sterile liquid at the end of the liquid column, with the electric current in its application flows along the liquid column and the liquid is heated to the desired temperature. The respective ratios of the cross-sectional areas of the liquid within of the container and after the point of confluence with the cross-sectional area within the liquid column should each be sufficiently large to ensure that a noticeable heating occurs only within the liquid column and not in any substantial way Dimension inside the container or after the point of confluence.

When the electrical alternating current over the entire length is applied to the column of liquid, there will be generally and essentially no exposure time at or in the area the maximum temperature reached.

If the liquid is to be heated by means of an electrical alternating current, it becomes the liquid column

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forming opening preferably by a perforation Dimension formed in the lower wall of the container intended for receiving the liquid to be treated ο To avoid the deposition of festera, in the liquid To restrict the material contained at the mouth to a minimum »the mouth suitably has the shape a perforation with broken edges in a thin-walled strip of insulating material with a low Coefficient of friction.

As an example to illustrate this feature of the device, a suitable column of liquid orifice was created by poking a 0.3 cm diameter hole in a strip of polytetrafluoroethylene film 0.005 cm thick. When used to form a column of milk, which was then heated by applying a current of 50 Hz at 400 mA and with a total output of 2.2 kW, a microscopic examination of the mouth showed no deposits of milk solids, although the milk was continuous during operation was subjected to ^{a temperature of about 80 °} C. under atmospheric pressure for 20 minutes.

A typical embodiment of the invention is now only for example with reference to the attached f-chemical drawings explained in more detail. It shows:

FIG. 1 is a partially sectioned, schematic circuit diagram the device, which has the means for generating the liquid column, for heating and Cooling shows, as well as the attachments for supplying and receiving the fluid and for Heating of the flow column column by microwave radiation,

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Fig. 2 shows an enlarged cross section through the means to form the fluid column and the waveguide heater and

Fig. 3 shows an enlarged cross-section through the coolant. where the flow of the flow is shown «.

The device shown schematically consists essentially of a vertically arranged tube 10 which forms the flow beam column and which has a carefully machined mouth 11 at its lower end 11 which is produced by conical machining of the tube wall. The tube 10 is mounted unü hub its lower end. just above the mouth is a hollow bearing book 12, which is attached to an enlarged outer first part 13 which is provided with a vertically arranged cylindrical bore »which runs coaxially to that of the bearing block, the first part 13 in one piece with a horizontally arranged waveguide 14 is formed with a right-angled cross-section * A second extended part 15 »which also has a cylindrical bore coaxial to that of the first part and is also formed in one piece with the waveguide» is formed on the lower side of the waveguide. The second part 13 is arranged directly over a "plan" which consists of two removable parts, the upper part 16 of which has a slightly larger bore than the lower part 17, the bores of both parts of the flange being coaxial with the bores of the two enlarged parts 13 and 15 run.

A tube 18 made of ceramic material is arranged vertically inside the waveguide and resting both on the bearing block 12 and also on the lower flange part 17, the upper and lower edge of which each sealingly ax the bearing block \ 2

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or the lower flange part 17 is connected via silicon rings 19 i3t.

the i7ellenlliters 14 is a closely connected « horizontal extension piston 20 on the right side ei es KeramilU'ühroG 18 slidably arranged, as from the ' Drawing can be seen. The waveguide 14 is also provided with first and second stub bulbs 21 and 22 provided, each of which is arranged inside recessed ayliiidov: .ach3r housing 23 and 24, which right / incolxg to the waveguide and from above or attached to the bottom opening in the waveguide are. The steel pipe pistons and their respective housings are offset from one another on the left side of the ceramic tube 18, as also shown in the drawing can be found.

The lower part 17 of the flange is forked on a hollow housing attached, which has a single; conical tapered upper leg 25 and a first and a second lower leg 26 and 27 respectively. The first lower leg 26 is vertical and coaxial below the tube 10 forming the liquid column and the ceramic tube 18 arranged. The bore of the upper leg 25 and the first lower leg 26 is wider than that of the ceramic tube 18 to a free and unimpeded passage of a column of liquid, not shown, through this Area of the device to enable when it is in operation. The second lower leg 27 is after inclined at the bottom and attached to the first leg 26 at an acute angle.

Inside the fork-shaped hollow housing and pivotable

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connected to the wall of the second lower leg 27, a deflecting member 28 extending upward is arranged. The walls of the forked hollow housing are also provided with three laterally arranged viewing windows 23, a light source 30 and an access opening provided with an encapsulated thermocouple 31, wpfooi the probe 32 of the thermocouple can be retracted and inserted into the path of the liquid column, not shown.

The lower end of the first leg 26 is connected via a planar 33 to a mixing chamber 34 which has a number of downwardly directed inlet tubes 35 which extend through horizontally opposed inlets in the chamber wall. Inside the chamber 34 and below the inlet tubes 35 is a thin-walled, conical hopper 36 disposed _t which is intended to receive an association of fluids which enter the chamber 34 from these inlet tubes and from the liquid column. the mixing chamber 34 is eating over a container 37 for receiving the fluids from the mixing chamber arranged «

The mixing chamber 34 and the container 37 are shown in section in FIG Fig.3 is shown schematically, with a heated column of liquid a is shown, which is mixed with a cooled liquid b, which into the chamber 34 via the inlet tubes 35 enters and wherein the combined liquids are discharged into the container 37 as liquid c will.

Am feed tank 38, which contains the liquid to be treated av. takes, 1st with the tube 10 forming the liquid column via a feed-measuring pump 39, a measuring instrument for the hydraulic pressure, which is denoted by 40, a

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Throttle 41 and a feed pipe 42 connected. One with one The hydraulic accumulator 43 provided with a hydraulic accumulator 43 provided with a soleplate KolHjan 44 is connected to the feed pipe 42 between the throttle 41 and the Sgeiss-Meßpuapa 39 connected. The hydraulic one Accumulator is controlled by gas supplied from a gas cylinder 45.

The container 37 is provided with a sample tube 46 and with a Outlet pipe 47 provided ^ which is intended to the to be treated liquid via a circulation pump 48 to a Cooling component 49 and from there via a cooling coil 50 to lead to a manifold 51 within the cooling unit. The manifold is designed to represent the flow split the cooled liquid for delivery to the inlet tubes 35. A steam supply line 52 with Valve is also located between the cooling coil and the manifold. The container 37 is still connected to a gas cylinder 53 and a gas pressure meter 54.

The lower end of the second leg 27 is connected to a container 55 linked for waste products.

The left leg of the waveguide 14 is - as shown * connected to a magnetron 56, the Energy to operate the magnetron from a power transformer 57 is obtained; which with an electric Energy source 58 is connectable

The operation of this preferred form of execution of the » inventive device is now for example in the Application for the sterilization of milk explained.

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Before being put into operation, the device was first sterilized by flooding with live steam through the steam line 52 and then with eau ^ -s-Söff-free nitrogen from a gas cylinder 53 under a pressure of 1? _S 5}; & / cai

Iia food tank 36 containing, fcosaogenized and pasteurized milk was pumped via the MeiJpusape 39 and the feed line to the oil-liquid column-forming rotor 10, the flow rate through the hydraulic accumulator: 43 being stabilized. 'Its stable, non-exhausted column of milk was passed through the dia »lie S & ila picture and e discharge V \ erse'cjt, and fell under the influence of gravity in the vertilcals ^ * direction, but without physical correc- tion through the ceramic tube 18 and the upper part Leg 25 of the gabc?, 2'önaijg-5S ':. Part to go over the Utalenkglisd 28, which was shown in the broken lines in Fig. 1; *; - position göbrscb ν, in the second lower leg 2? and from there to the container 55 for waste products.

Once it is determined by the Sicatfenster 29 was _t that a stable liquid column had formed was _t a erzeuß by AEA excited magnetron 55; e microwave radiation along the W eil en .- urther 14 by the transmitting ceramic tube 15 to the Plüesi ^ lrai within the Keranikrohrs! Transfer · When the microwaves. Energy of the Beiastuns through the liquid column by adjusting the pistons 20, 2 * 5 and 22 was adjusted. In order to obtain the desired heating indicated by the thermocouple 31, the probe of the Tftermoeltmentea was withdrawn and the deflecting member 28 was swiveled out of the path of the liquid column into the position shown in continuous lines in FIG. With that it became the column of liquid en & Belicbt «through the first lower one

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Leg 26 to fall through to the conical funnel, and it was then mixed by mixing with part of the previously sterilized and pre-chilled milk, which via the manifold 51 and the "inlet tubes 35 was fed.

^{The column of milk was heated to 193 0} O during its passage through the ceramic waveguide and this temperature was maintained during its passage through the fork-shaped housing (0.15 seconds) to the point at which it was in the previously sterilized, pre-cooled milk conical funnel 36 was mixed. A M

Part of the sterilized milk was removed from the container 37 via the outlet pipe 47 of the cooling unit 49, where the Milk was cooled and passed to the manifold 51. Parts of the milk were bottled! on bottles and for sterility tests also withdrawn from the container 37 via the sample tube 46

example 1

This example relates to the sterilization of milk using the device described above with reference to the echemical drawings.

The parts of the device through which the milk is passed were first sterilized ^{by passing steam at 130 °} C. through them for one hour, with parts of the steam condensate being diverted for sterility tests. None of these samples could be found to contain bacteria.

Homogenized and pasteurized milk at a local

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Dairy wuröe in aas system introduced and the milk "column was & nf accessible to the waste tank 55 umgeleitetβ währsnö AEIE temperature of MiXchsäule on AEEN ER-

. Value of 193 ⁰ C by suitable setting of the

Microwave energy was increased because it soon became stable The milk column auQgeMlöe'j-hatt ^ became that limped out of the path of the column 'genchwesikt and after Einwirlcuagsaeit of 0.15 see was the ο column of milk on her lower "end aniäaglich by irritation of four rays cooled down with a cooled steam cooker. As soon the concentration of the milk in the condensate has a suitable value had reached, samples of the treated milk were withdrawn for sterility tests, which were carried out as follows:

Exactly twenty 100 ml of the treated milk were mixed with Laokmus and the first half thereof was subjected to an incubation period of 21 days at 30 ⁰ C and the second half at 55 ⁰ O. A further sixteen 300 ml were ^{stored after mixing with litmus at 30 °} O for 40 days. No contamination was observed

As a control, equal amounts of ufo-treated milk were used he same delivery saved mvfcer ideal conditions and in all cases there were visible afflictions as signs for contamination to be seen within two or three days (such as color loss, clumping and Elimination of components).

Portions of the treated milk were in the neutral form of a committee of professionally trained taste stewards Control amounts of untreated pasteurized milk were compared using an erectile test. the

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Majority of the taste testers were unable to between the control samples and the treated milk samples and it was not used by any of the taste testers found that the treated specimens anawning of food snacks - or loss of color or a ver ~ have changed structure »

This example depicts rlie sterilization of cream and follow exactly the procedure described in example 1 »

! Un panel of professionally trained taste testers reported no noticeable difference between the treated and the untreated samples.

Twenty-four 100 ml samples of the cream were tested for sterility and none showed bacterial contamination after an incubation time of 21 days at 4 ^° C. or at 15 ^{° C.}

This example describes the sterilization of orange juice and following exactly the procedure, which was described in Example 1, except that the orange juice was sterilized at a heating to 120 ⁰ G while 0.15 lake.

! A panel of professionally trained taste testers found no taste or other difference between the treated and untreated samples.

Twelve 400 ml samples of the orange juice were tested for

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The sterility was checked and no sample showed any contamination ^{after an incubation time of 21 days at 15 ° C.}

Example ^ 4

This example relates to the treatment of skimmed milk which is deliberately treated with heat-resistant spores of the organism Ba cillus subtilis A (Ridgeway JD 195Ö "The incidence and thermal resistance of mesophilic spores found in milk and related environments", J. Appl. Bact. 2_1 »11 & ) was vaccinated.

The results of this experiment, as shown in Table 1, show that a temperature of 190 ^° C. was the minimum required to obviously destroy all spores of this organism.

TAF ⁷ SL 1 Reduction of spores of B. subtilis A contained in skimmed milk and exposed to a microwave "heating" during various * working temperatures (exposure time 0.15 seconds) (Ridgeway 1958)

^v \ number of over-reduction

Temperature start Vaccination live spores / ml in

minimum Concentration / ml after ( 1st treatment % 190 ⁰ C 1.57 χ 1O ⁷ 7th 99.999901 18O ⁰ C Il 16 99.9999 159 ⁰ C Il 433 99.9973 142 ⁰ C Il 1 * 4 χ 1O ⁵ 99.112 Example 5

This example relates to the treatment of pasteurized, homogenized milk which has been deliberately inoculated with the resistant spores of the organism Bacillus aubtilia A (Ridgeway 1958).

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The results of this experiment shown in Table 2 show that a temperature of 190 ° was required to in the v / it borrowed all spores to destroy this organism «

TAFSL 2

Reduction in pasteurized, homogenized milk contained in "microwave heating" at different working temperatures (exposure time 0.15 seconds) spores ^from B · aubtilis ^ A (Ridgeway 1956)

Tea perature
m in imum ______ Initially vaccination
Cons ent rat ion / ml 10 ^b . Number of over
live spores / ml
after d. treatment 1.5. reduction
in
4> 19O ° C 4.5 χ 10 ⁵ 3.03 99.99997 19O ⁰ C 3.55 x 10 ⁶ 10 99.9997 175 ° C 3.25 x 10 ⁶ 10 99.999 16O ⁰ C 3.25 χ 10 ⁵ χ 10 ³ 99.999 151 ⁰ C 9.5 χ 10 ⁶ 1.4 χ 10 ³ 99.886 145 ⁰ C 3.25 x 10 ⁵ 2.6 χ 10 ⁵ 99.92 13O ⁰ C 9.5 x 1.5 Patent claims: 84.3

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Claims (1)

Godfather η ta η s ρ rü che Procedure for the sterilization of a liquid characterized * that from the liquid a flowing stream not carried by any solid surface is formed that this stream is suitable for sterilization of the food is heated to a temperature of at least 100 ° G for a sufficient period of time while it is held without contact with a solid surface, and that the flow of liquid food then is cooled below a temperature at which notable thermochemical changes can take place, while still being held out of contact with a solid surface. 2. The method according to claim 1, characterized in that the heated, liquid food with a cool, sterile stream of the same food is mixed. 3. The method according to any one of claims 1 or 2, characterized in that the time interval between the The heating of the liquid food and the cooling of the liquid food is not longer than 1 second. 4. The method according to any one of the preceding claims, characterized in that the stream of liquid food is heated by passing through it Alternating current conducts. 5 · Method according to one of claims 1, 2 or 3 » characterized in that the flow of liquid life BADORIGlNAt 109831/1632 _ ^ _ 169222Q as by means of being heated by giving it a microwave radiation suspends. 60 The method according to any one of the preceding claims, characterized in that the liquid food is heated ^{to a temperature between 180 0} G and 220 ^{0 C for a period of time between 0.4 and 0.1 seconds.} 7. The method according to any one of the preceding claims, characterized in that the liquid food in a gas atmosphere under a larger ala the atmospheric one Pressure is heated. 8. The method according to claim 7, characterized in that the gas is an inert gas with a pressure between 14 and 28 kg / cm ² . 9. Device for Steriliai even a liquid LebensraittäLs, characterized by means (11) for the formation of an unsupported stream:? » the liquid foodstuff, means (H, 10) for door heating the stream without contact with any solid surface and means (35) for cooling the heated food stream by mixing it with a cooled, sterile liquid. 10. The device according to claim 9t, characterized in that that the heating means comprises a waveguide (14) through which the unsupported flow of liquid food is passed and through which one Microwave radiation for heating the liquid stream can be transferred. 11. The device according to claim 10, characterized in that that a radiation transmitting tube (18) within 109831/1632 Ai of the waveguide is provided, which the path of the enclosing unsupported fluid streama. 12. The device according to claim 9, characterized in that » that the heating means "comprise means for generating an alternating electrical current through the flow of the liquid Direct food. 13 «Device according to one of claims 9 to 12, characterized in that it comprises means to in the the trajectory of the unsupported flow of liquid food surrounding the area is higher than that of the atmosphere To maintain gas pressure " 109831/1632 Blank page