SYSTEM FOR PROCESS MONITORING OF MEDIA TREATMENT, IN PARTICULAR HACCP-COMPLIANT SYSTEM FOR FOOD PRESERVATION

Description

[0001] The present invention relates to a system for process monitoring of the treatment of media, in particular a HACCP-compliant system for the preservation of food.

[0002] The present description also includes an exemplary procedure for monitoring a process for treating media, in particular a HACCP-compliant procedure for preserving food.

[0003] Quality assurance plays a crucial role in the production and handling of food. The EN ISO 9000 series of standards documents the principles for quality management measures and facilitates mutual understanding of quality management systems at the national and international levels. The Hazard Analysis and Critical Control Points (HACCP) concept is a clearly structured, preventative tool designed to avoid foodborne hazards that could lead to illness or injury in consumers. Both German food hygiene regulations and a European Community regulation mandate the application of the HACCP concept in all companies involved in the production, processing, and distribution of food.

[0004] Quality assurance encompasses various approaches and measures to ensure that defined quality requirements for the final product are met. One quality characteristic of media, especially food, is its shelf life. To extend the shelf life of food, there are a wide variety of preservation methods that stop or at least slow down the spoilage of the food and its ingredients into inedible or harmful decomposition products. The decomposition that preservation is intended to prevent usually occurs through biochemical processes such as microbial or enzymatic activity. The most common application is the preservation of food in industrial production, which on an industrial scale is achieved, for example, through heating, distillation, cooling, or other methods.

[0005] Electroporation is a method of making cell membranes temporarily or permanently permeable. This technique is used, among other things, in microbiology to introduce DNA into cells. Electroporation is also used in food and bioprocess engineering to improve mass transport processes or to inactivate microorganisms.

[0006] One advantage of electroporation is that it is a non-thermal process and can therefore be used to preserve temperature-sensitive media, such as dairy products, fruit juices or smoothies, by inactivating microorganisms.

[0007] Electroporation involves generating short pulses of electric fields that perforate cell membranes. A variety of parameters are crucial for successful electroporation, such as the strength of the electric field, the pulse shape, the number of pulses, and the pulse duration. There are no established standards regarding dose or intensity for treating media using electroporation. Therefore, the process parameters are selected and optimized by the user on a case-by-case basis, which is time-consuming and requires a high level of technical and scientific expertise. For example, a device for the continuous treatment of free-flowing foods using electric fields is shown in US4838154.

[0008] The object of the present invention is therefore to provide a system for process monitoring of the treatment of media, which can be standardized and reliably ensures the successful treatment of the media.

[0009] The aforementioned system for process monitoring of media treatment solves this problem through the features of claim 1.

[0010] In the example mentioned at the beginning, the medium is treated with a pulsed field, the change in a state parameter of the medium caused by the treatment with the pulsed electric field is determined, the determined change is compared with a predetermined target change value, and a warning signal is issued if the difference between the determined change and the predetermined target change value exceeds a limit value.

[0011] By coupling an electroporator with a measuring device and an evaluation device, it becomes possible to reliably and in a standardized manner ensure the intended electroporation treatment of the medium. This is achieved by the system monitoring the change in a specific state parameter of the medium being treated due to electroporation and determining whether this change corresponds to a target change value within the range of usual tolerances. Adherence to these tolerances ensures that the treatment was successful, for example, that a food product was preserved according to specifications. Furthermore, the system according to the invention immediately issues a warning if the electroporation (hereinafter also referred to as PEF (Pulsed Electric Field) treatment) did not have the desired effect, for example, if the number of harmful microorganisms in the medium was not reduced to a desired minimum.

[0012] Under a "Medium" For the purposes of this application, "substance" refers to a material or substance. This includes, in particular, foodstuffs.

[0013] Under a "Treatment" A process is understood to be one that alters parameters of the medium, for example, by causing a structural or material change. Treatments within the meaning of the present invention include preservation as a means of extending the shelf life of foodstuffs, which depends in particular on the number of harmful microorganisms in the medium.

[0014] A "State parameters" (or state variable) is a macroscopic physical quantity that describes the state of the medium, for example pressure, temperature, volume, number of particles or amount of substance, entropy, enthalpy, pH value or microbial load or number of microorganisms.

[0015] The "Target change value"The target value is a predetermined and specified value of the state parameter, which is characteristic of the successful completion of the desired treatment of the medium. The target value can be determined through standard laboratory-scale tests.

[0016] Under a "Warning signal" Any type of signal output by the evaluation device indicating that the specified target change value has not been reached, thus indicating a malfunction and unsuccessful PEF processing of the medium, is to be understood as a warning signal. Possible warning signals include visual signals, audio signals, or electrical / data signals that can be detected by a receiver, such as the system operator or a display unit like a lamp, speaker, or computer.

[0017] The "Limit"reflects a tolerance range around the specified change target value, whereby the difference takes into account both deviations above and below the change target value and can thus cover both undertreatment (i.e., insufficient treatment) and overtreatment (i.e., excessive treatment of the medium).

[0018] The invention can be further improved by the following developments and advantageous embodiments, each of which is advantageous in itself and can be combined with each other as desired.

[0019] The system further includes a conveying system for transporting the medium. The system can be configured for continuous process monitoring, preferably online, or for batch monitoring, in which the medium is transported along the conveying system to the electroporator, processed within the electroporator, and then discharged from the electroporator. In an exemplary process, the medium can therefore be conveyed to and from the electroporator both continuously and intermittently. The conveying system can consist of a pipeline and / or a conveyor belt. Pipelines are suitable for processing pumpable media, such as liquids like fruit juices, smoothies, or dairy products. For solid media or bulk materials, a conveyor belt or screw conveyor can be used as the conveying system.The system includes a drive for transporting the medium, for example, a pump or a motor. The system comprises a conveying system with a conveying path and a drive for transporting the medium along the conveying path.

[0020] According to a further embodiment, the electroporator can have at least two electrodes connected to a pulse generator. The electrodes, even if they do not need to come into direct contact with the medium to be treated, are preferably made of stainless steel or titanium. The two electrodes form a capacitor, and the space between them forms the treatment chamber of the electroporator, in which the pulsed electric field is generated. The electrodes can be arranged coaxially, collinearly, conically, or parallel to each other and generate a homogeneous electric field for uniform treatment of the medium. The pulse generator, serving as the voltage source, can, for example, be a high-voltage pulse generator, such as a Marx generator, capable of generating electrical pulses of high voltage in the kilovolt range and short duration in the microsecond to millisecond range.

[0021] The system further includes a control unit for setting the conveying speed of the transported medium and / or at least one operating parameter of the electroporator. The control unit can, for example, adjust the drive speed to achieve a desired conveying speed. The control unit, which can be connected via a control line to the conveying section or the drive and / or the electroporator, in particular its pulse generator, can set operating parameters of the electroporator such as the generated field strength, pulse duration, pulse frequency, pulse shape, pulse voltage, current, and / or the specific energy introduced into the medium to be treated per unit of time to a desired value.

[0022] In an exemplary process, the conveying speed of the transported medium and / or an operating parameter of the electroporator, such as the field strength, pulse duration, pulse frequency, pulse shape, pulse voltage, polarity, current and / or specific energy, can be set.

[0023] The system according to the invention can further comprise a blocking device for preventing the medium from exiting the system when a warning signal is issued. The blocking device can, for example, include a valve which closes when a warning signal is issued by the evaluation device, thus preventing the medium from exiting the system. The blocking device can also be configured to reverse the transport direction of the medium and prevent its further flow along the process line. The blocking device can be coupled to the evaluation device via a signal transmission mechanism, so that the medium's exit is automatically prevented as soon as a warning signal is issued by the evaluation device. This coupling can be either direct or indirect, for example, via the system's control unit.

[0024] When the present application refers to coupling or data transmission, this includes both wired and wireless coupling or transmission, for example via cables or radio technology. In the exemplary method, the release of the medium can therefore be automatically stopped when a warning signal is issued.

[0025] In a further embodiment, the measuring device comprises at least one thermometer for determining the temperature rise. The measuring device includes at least one inlet thermometer for determining the medium temperature before entering the electroporator and at least one outlet thermometer for determining the medium temperature after exiting the electroporator, thus enabling the temperature rise to be determined during continuous operation. Surprisingly, it has been found that the temperature rise is a reliable parameter of the medium, characteristic of successful medium processing, particularly with regard to the preservation of foodstuffs through the inactivation of microorganisms.The measuring device, namely the at least one input thermometer and the at least one output thermometer, can be connected to the evaluation device via signal transmission and in this way transmit the determined change in the state parameter, for example a temperature increase, from the measuring device to the evaluation device.

[0026] Furthermore, the conveying velocity of the medium during transport through the electroporator is determined. The system includes a velocity sensor to measure the conveying velocity of the medium transported through the electroporator along the conveying path. The velocity sensor can, for example, contain a flow meter that outputs a flow signal characteristic of the conveying velocity. In this way, the quantity of the transported medium conveyed per unit of time can be determined.The measured conveying speed can be output to the control unit, which in turn adjusts the parameters of the electroporator based on the measured conveying speed to ensure that the medium is adequately treated during proper operation, for example, that the energy required for the inactivation of microorganisms is introduced into the medium by the electroporator. The speed sensor also enables a closed-loop control system to maintain a specific conveying speed.

[0027] In another embodiment, the system includes an energy measurement unit for determining the specific energy input into the medium during treatment with the pulsed electric field. An oscilloscope, for example, can be used as the energy measurement unit. The energy measurement unit can determine the specific energy input as a function of the measured conveying speed and the operating parameters of the electroporator. If the energy measurement unit is coupled with the control unit, a closed control loop can be established, which ensures that either the conveying speed and / or the operating parameters of the electroporator are adjusted accordingly to achieve a specific energy input into the medium during treatment in the electroporator, which is required for the intended treatment of the medium.

[0028] Furthermore, the evaluation device includes a unit for comparing the measured temperature rise of the medium with a predetermined temperature rise and for issuing a warning signal as soon as the difference between the measured temperature rise and the predetermined temperature rise exceeds a limit. This embodiment is based on the surprising finding that the introduction of a specific amount of energy into the electroporator, which is required for the inactivation of microorganisms, is macroscopically reflected in a specific temperature increase of the medium. Although electroporation is fundamentally a non-thermal treatment method, slight temperature increases of around 20° to 30°C can nevertheless occur, which can be used as a measure of successful food preservation.According to one embodiment, the target temperature increase can be calculated using the following formula: . ΔT = W spec c p ∗ f , where W spec = specific energy input, cp = specific heat capacity of the product, and f = correlation factor. The correlation factor depends, among other things, on the medium being treated, its pH value, and / or the treatment intensity in the electroporator.

[0029] According to a further embodiment, the system can include a logging unit for recording the system's operating parameters. All system parameters, such as the medium's flow rate, pH value, pressure, temperature, or electroporator's operating parameters, can be recorded and stored, for example, in a memory of the logging unit, particularly over time.

[0030] The protocol unit enables documentation of the system according to the invention during operation and simplifies troubleshooting or allows conclusions to be drawn about the treatment of certain batches of the medium that may not have been treated properly.

[0031] According to a further embodiment, the system can also include a pressure measuring unit for determining the pressure in the medium. This allows it to detect whether the treatment section is filled with product and whether sufficient back pressure exists to suppress the release of dissolved gases. In particular, the pressure measuring unit can also measure the pressure in the medium after treatment in the electroporator. In this way, for example, over-treatment of the medium in the electroporator can be detected, which might be reflected, for instance, in foaming due to an undesired chemical reaction and a corresponding pressure increase in the medium. The system can also include an overpressure indicator for issuing a warning signal as soon as the measured pressure in the medium exceeds or falls below a predetermined maximum pressure. The overpressure indicator can be integrated into the pressure measuring unit so that the pressure measuring unit can directly issue the warning signal, e.g.,emits an alarm tone. The overpressure indicator can also be included in the evaluation device, so that the evaluation device can output various types of warning signals, for example, a warning signal in the event of an undesired overpressure and another warning signal in the event of an undesired deviation from a predetermined target value, for example, a desired temperature increase during treatment in the electroporator.

[0032] It may also be provided to measure the pH value of the medium, in particular the pH value before it enters the electroporator. The system according to the invention can therefore include a pH measuring device for determining the pH value of the medium, preferably the medium before it enters the electroporator. The pH value of the medium can be a measure of the microbial load of the medium. Experience has shown that the microbial load of a medium is lower the more acidic or alkaline the medium, i.e., the further the pH value of the medium deviates from the physiological pH value (neutral pH value around pH 7). By determining the pH value using a pH measuring unit, an estimate of the microbial load of the medium to be treated can thus be made. This estimate can, in turn, provide information about how much a state parameter of the medium needs to be changed in the pulsed electric field.The target pH value can thus be preset based on the measured pH value and, if necessary, continuously adjusted during operation. Furthermore, measuring the pH value allows differentiation between a medium and water (e.g., with cleaning solution) in the system. Once a medium is present, the system can be operated at the desired performance / intensity. For this purpose, the pH measuring unit can be connected to the evaluation electronics and / or the control unit via signal transmission. The system can also be preset to a pH value or pH range for the medium to be treated, which is characteristic of the medium's optimal condition. For some media, for example, acidification may be necessary. If the acidification step is inadvertently omitted, the medium's pH value will be outside the predetermined range, which can be detected by the pH measuring unit.In this case (the pH value of the medium determined by the pH measuring unit is outside the pH range predetermined for this medium), the system according to the invention can issue a warning signal.

[0033] The invention is explained in more detail below by way of example with reference to advantageous embodiments shown in the drawing. The advantageous developments and embodiments shown are independent of each other and can be combined as required in any application.

[0034] It shows: Fig. 1 shows an exemplary embodiment of a system according to the invention for process monitoring of the treatment of media.

[0035] The following is an exemplary system 1 for process monitoring of media treatment with reference to the schematic representation in Fig. 1This presentation introduces an exemplary method for monitoring a process of treating a medium, particularly using the system according to the invention, for example, the exemplary system of Fig. 1 how it can be carried out is explained.

[0036] The in Fig. 1 The system 1 shown comprises an electroporator 2 for treating a medium 3 (in Fig. 1(schematically represented by black dots) with a pulsed electric field. The system 1 further comprises at least one measuring device 4 for determining a change in a state parameter of the medium 3 caused by treatment with the pulsed electric field, and an evaluation device 5 for comparing the determined change in the state parameter with a predetermined target change value and for outputting a warning signal as soon as the difference between the determined change and the predetermined target change value exceeds a limit value.

[0037] In the embodiment shown, the system 1 according to the invention comprises a conveying section 6 for transporting the medium 3, for example, the food to be preserved. In this exemplary embodiment, the conveying section 6 comprises Fig. 1A pipeline 7 in which pumpable media, such as juices, smoothies, or dairy products, can be transported. The conveying section 6 can alternatively include a conveyor belt or a screw conveyor (not shown) if, for example, solid media and bulk media are to be handled.

[0038] System 1 further comprises a drive 8 for transporting the medium along the conveying path 6. The drive 8 can, for example, be a pump that pumps a flowable medium through the pipeline 7, or a motor that drives a conveyor belt or a screw conveyor. The conveying path 6, in the illustrated embodiment a pipeline, and the drive 8 together form a conveying system 9.

[0039] The conveying section 6 runs through the electroporator 2, or in other words, the electroporator 2 is arranged such that a medium 3 transported on the conveying section 6 can be treated with a pulsed electric field. The electroporator 2 comprises at least two electrodes 10, which form a capacitor 11 for generating an electric field in a treatment section of the conveying section 6. The electrodes 10 of the capacitor 11 are connected to a voltage source 13 via power lines 12. In the illustrated embodiment, the two electrodes 10 of the capacitor 11 are arranged on opposite sides of the conveying section 6 and parallel to each other. With such an electrode arrangement, a homogeneous electric field can be generated for the uniform treatment of the medium 3. However, other variants of the electrode arrangement are also conceivable, for example, a coaxial, collinear, or conical arrangement.

[0040] A pulse generator 14, for example a high-voltage pulse generator such as a Marx generator, can be used as a voltage source 13. This generator can produce electrical pulses of high voltage in the kilovolt range and short duration in the micro- to millisecond range. The electrodes 10 can be made of, for example, stainless steel or a titanium alloy.

[0041] The exemplary system of Fig. 1The system further comprises a control unit 15 for adjusting the conveying speed of the transported medium 3 and / or at least one operating parameter of the electroporator 2. The control unit 15 can be connected to the drive 8 via a control line 16 and thus adjust the conveying speed, for example, the flow rate of the transported medium in the pipeline 7, by controlling a pump. In the illustrated embodiment, the control unit 15 is connected to the electroporator 2 via a further control line 17 and can thus control, for example, the field strength, pulse duration, pulse frequency, pulse shape, pulse voltage, current, or the specific energy input of the electroporator. Of course, control lines 16 and 17 can be omitted if data transmission between the control unit 15 and the drive 8 or electroporator 2 is wireless, for example, via a radio connection.The arrow of the control lines 16 and 17, which point towards the drive 8 and the electroporator 2 respectively, indicates that a control signal can be output from control unit 15 to the drive 8 and electroporator 2 via these lines. Even if this is in . Fig. 1 Not shown, the control lines 16 and 17 can also be bidirectional, meaning that signals from the drive 8 or electroporator 2 can also be transmitted back to the control unit 15. For example, the drive 8 can send a delivery signal via the control line 16 back to the control unit 15, which is characteristic of the drive's operation, e.g., the pump pressure.

[0042] All lines presented within the scope of this invention can be designed to be either wired or wireless, and signals or data can be transmitted via these lines not only in the direction indicated by arrows, but also in the opposite direction.

[0043] In the exemplary system 1 of the Fig. 1 Thus, the specific energy introduced by the electroporator 2 into the medium conveyed on the conveying path 6 during its treatment can be set via a control system for both the conveying speed of the drive and the operating parameters of the electroporator.

[0044] In the illustrated embodiment, the system 1 further comprises a measuring device 4, namely a velocity sensor 18 for determining the conveying velocity of the medium 3 transported along the conveying path 6 through the electroporator 2. The velocity sensor 18 can be configured as a flow measuring unit through which a flow signal can be output. This flow signal can be transmitted from the velocity sensor 18 to the evaluation device 5 via a signal line 19. In the evaluation device 5, the flow signal can be compared with a target value.If the current flow signal deviates from the target signal, the evaluation device 5 can output a control signal to the control unit 15 via a further signal line 20, which in turn forwards a control signal to the drive via signal line 16, thereby realizing a closed control loop for regulating the flow rate in the system 1 according to the invention. Of course, it is also possible for the speed sensor 18 to transmit the signal characteristic of the conveying speed directly to the control unit 15. Furthermore, the speed sensor 18 can measure the resistance or conductivity of the medium 3 located on the conveying path 9 and output a corresponding signal that is characteristic of the conductivity or resistance of the conveyed medium. This makes it easy to determine whether medium 3 is being conveyed at all.Furthermore, conclusions can be drawn about the conveyed medium, and the value characteristic of the resistance or conductivity of the medium 3 can also be taken into account by the evaluation electronics 5 or the control unit 15 in order to precisely adjust the specific energy input.

[0045] It is of course also possible, even if this is in Fig. 1 Not shown, a further measuring device is to be provided which measures the resistance or conductivity of the medium 3 on the conveying section 6 and is designed to output a signal characteristic of this parameter. A conductivity measurement also makes it possible to determine whether medium 3 or water (possibly with cleaning agent) is present in the conveying section 6.

[0046] The in Fig. 1The system 1 shown further comprises a pH measuring unit 21 for determining the pH value of the medium 3 before it enters the electroporator 2. This additional measuring device 4, the pH measuring unit 21, is therefore to be arranged upstream of the electroporator 2 in the direction of flow, which is represented by an arrow in the pipe 7. This is not strictly necessary for the velocity sensor 18. It can also be arranged downstream of the electroporator 2 in the direction of flow.

[0047] The pH value of medium 3 can be characteristic of the contamination of medium 3 with harmful microorganisms. Acidic or alkaline foods, whose pH values ​​are further away from the physiologically neutral pH of 7, tend to have lower levels of harmful microorganisms. A lower microbial load, in turn, means that less specific energy input from electroporator 2 into medium 3 is required to process the medium 3 to such an extent that the microbial load is reduced below a maximum level necessary to extend its shelf life.

[0048] In the illustrated embodiment, the pH measuring unit 21 is connected to the evaluation unit 5 via a further signal line 22. A signal characteristic of the pH value of the medium 3, determined by the pH measuring unit 21, can thus be output to the evaluation unit 5 via signal line 22. The evaluation unit 5 can output this signal via signal line 22 to the control unit 15, which in turn outputs a corresponding control signal via line 17 to the electroporator 2 in order to specifically adapt the electroporation treatment to the medium 3.

[0049] In the exemplary embodiment of the Fig. 1System 1 comprises at least one thermometer for determining the temperature rise. The temperature is used as a state parameter, which the evaluation device 5 utilizes as will now be explained in more detail. In the illustrated embodiment, system 1 has at least one inlet thermometer 23 for determining the medium temperature before entering the electroporator 2 and at least one outlet thermometer 24 for determining the medium temperature after exiting the electroporator 2. The difference between the inlet and outlet temperatures corresponds to a temperature difference, which, in the exemplary embodiment, corresponds to the determined change in a state parameter and is compared in the evaluation device 5 with a predetermined target change value, i.e., a predetermined target temperature difference.

[0050] The input thermometer 23 and output thermometer 24 are connected to the evaluation unit 5 via signal lines 25 and 26, respectively. Temperature signals can be output from thermometers 23 and 24, which are then transmitted to the evaluation unit 5 via the corresponding signal lines 25 and 26. The evaluation unit 5 compares the input and output temperatures and first calculates the temperature difference as the determined change in the state parameter. Within the evaluation unit 5, the determined temperature difference, i.e., the determined temperature rise of the medium 3, is then compared with a predefined target temperature rise. If the difference between the determined temperature rise and the predefined target temperature rise exceeds a predefined limit, the evaluation unit outputs a warning signal.The warning signal issued can be, for example, a visual or audio signal in the form of a warning light or a warning siren, indicating improper handling of the medium.

[0051] In the illustrated embodiment, the warning signal is first output by the evaluation unit 5 to the control unit 15 via the control line 20, which then transmits it via a further control line 27 to a blocking device 28. The blocking device 28 prevents the medium 3 from exiting the system 1 when the warning signal is output.

[0052] In the illustrated embodiment, the shut-off device 28 is designed as a shut-off valve 29, which is connected downstream of the electroporator 2 in the flow direction. As soon as a warning signal is issued by the evaluation unit 5, the shut-off valve 29 is closed and the escape of the medium 3 from the system 1 according to the invention is prevented. Alternatively, the actuator 8 could simultaneously be used as a shut-off device by stopping the actuator upon issuing a warning signal and halting the conveying of the medium 3 on the conveying section 6. Another possibility, not shown, would be to use a T-valve instead of a shut-off valve 29, which, during normal operation, i.e., when the medium is being handled correctly, discharges the medium 3 from the system 1.Upon receiving a warning signal, the output of the T-valve is switched, and the medium 3 is redirected via a bypass within system 1 and returned to the conveying section 6 at a point located upstream of the electroporator 2 in the direction of flow. The medium 3 could be circulated within system 1 via such a bypass line until the desired change in the state parameter of the medium is achieved and the warning signal is deactivated.

[0053] In the exemplary embodiment shown, the Fig. 1 The evaluation device 5 compares the determined temperature increase of the medium during treatment in the electroporator 2 with a predetermined target temperature increase and issues a warning signal as soon as the difference between the determined temperature increase and the predetermined target temperature increase exceeds a limit value.

[0054] The target temperature increase can be calculated using the following formula 1: ΔT = W spec c p ∗ f , where W spec represents the specific energy input, cp the specific heat capacity of the medium, and f a correlation factor. The correlation factor can, for example, take into account the type of medium, the desired treatment intensity in the electroporator, the pH value, the conductivity of the medium, or other factors.

[0055] To ensure that the electroporator 2 introduces the required specific energy input into the medium, the system according to the invention can include an energy measuring unit 30 for determining the specific energy input into the medium 3 during treatment with the pulsed electric field. The energy measuring unit 30 can determine the specific energy input as a function of the determined conveying speed and operating parameters of the electroporator 2. The operating parameters of the electroporator can be determined, for example, by an oscilloscope 31, which records the time course of the pulse voltages of the capacitor 11, including, for example, the pulse duration, pulse frequency, pulse shape, and, if applicable, the generated current. The parameters determined by the oscilloscope 31 can be transmitted from the oscilloscope 31 to the energy measuring unit 30 via a signal line 32.

[0056] In the illustrated embodiment, the oscillator 31 is shown as an integrated component of the electroporator 2. It is equally possible to integrate the oscilloscope into the evaluation unit 5 or to design it as a separate component.

[0057] In the exemplary embodiment shown, the energy measuring unit 30 is integrated into the evaluation unit 5. This is advantageous because the evaluation unit 5 receives a signal characteristic of the conveying speed via signal line 19 and the operating parameters of the electroporator 2 from the oscilloscope 31 via signal line 32. From these parameters, it can determine the specific energy input into the medium during treatment with the pulsed electric field. Of course, it is also possible not to integrate the energy measuring unit 30 into the evaluation unit 5, but to design it as a separate unit or even to integrate it into the electroporator 2. In the latter case, however, an additional signal line between the electroporator 2 and the velocity sensor 18 would be required.

[0058] The exemplary system 1 of the Fig. 1The system further comprises a pressure measuring unit 37 for determining the pressure in the medium 3 after treatment in the electroporator 2. The system can also include an overpressure indicator 38 for issuing a warning signal as soon as the measured pressure in the medium 3 exceeds a predetermined maximum pressure. In the illustrated embodiment, the overpressure indicator 38 is integrated into the pressure measuring unit 37 and can transmit the warning signal via a signal line 39 to the evaluation unit when a maximum pressure is exceeded. The evaluation unit can then initiate appropriate measures, such as blocking the discharge of the medium. The overpressure indicator 38 could also be integrated into the evaluation unit 5.In this case, the pressure measuring unit 37 would output a signal characteristic of the measured pressure in the medium via the signal line 39 to the evaluation unit 5, which compares this signal with a maximum permissible pressure and issues a warning signal if the pressure in the medium is exceeded. Monitoring the pressure in the medium 3 after treatment in the electroporator 2 is advantageous because a disproportionate pressure increase in the medium may be due to overtreatment of the medium 3 in the electroporator 2, i.e., excessive energy input, which manifests as undesirable foaming. Foaming leads to a pressure increase in the medium 3 and can be caused by undesirable reactions within the medium.

[0059] The system 1 according to the invention of the exemplary embodiment of the Fig. 1The system 1 also includes a protocol unit 33 for recording operating parameters of the system. The operating parameters, particularly their temporal progression, can be recorded in the protocol unit and stored for documentation purposes. In the illustrated embodiment, the protocol unit 33 is connected to the evaluation unit 5 via a signal line 34 for data and signal transmission. As indicated by the dashed box, the system 1 can have a central control unit 35, which comprises the evaluation unit 5, the control unit 15, and the protocol unit 33. The system 1 receives the signals for all determined operating parameters of the system 1 and outputs all control signals, including warning signals.

[0060] The control and monitoring unit 35 can have a data input interface to transmit the specified target change value to the evaluation unit 5. A graphical user interface can be provided through which the user can retrieve system information, intervene in the settings of system 1, or access data stored in the memory 34 of the protocol unit.

[0061] With the system 1 according to the invention, an HACCP-compliant system for preserving food can be provided, in which the killing of harmful microorganisms in the medium necessary for preservation, which is achieved by applying a pulsed electric field in the electroporator 2, is monitored by causing a specific temperature increase in the medium 3, which indicates the successful treatment for preserving the food and which, in the case of insufficient treatment, issues a warning and can prevent further processing of an improperly treated medium. Reference sign

[0062] 1 System 2 Electroporator 3 Medium 4 Measuring device 5 Evaluation device 6 Conveyor section 7 Pipeline 8 Drive 9 Conveyor system 10 Electrodes 11 Capacitor 12 Power lines 13 Voltage source 14 Pulse generator 15 Control unit 16 Control line 17 Control line 18 Speed ​​sensor 19 Signal line 20 Signal line 21 pH measuring unit 22 Signal line 23 Inlet thermometer 24 Output thermometer 25 Signal line 26 Signal line 27 Control line 28 Locking device 29 Locking valve 30 Energy measuring unit 31 Oscilloscope 32 Signal line 33 Protocol unit 34 Signal line 35 Control and monitoring center 37 Pressure measuring unit 38 Overpressure indicator 39 Signal line

Claims

1. A system (1) for process monitoring of the treatment of media (3), in particular HACCP-compliant system (1) for the preservation of foodstuffs, comprising: - a conveyor section (6) and a drive (7) for transporting the medium (3), an electroporator (2) for treating a medium (3) with a pulsed electric field, - a speed sensor for determining the conveying speed of the medium (3) transported on the conveyor section (6) by the electroporator (2), - at least one measuring device (4) for determining a temperature rise of the medium (3) caused by the treatment with the pulsed electric field, wherein the measuring device (4) comprises at least one input thermometer (23) for determining the medium temperature before entry into the electroporator (2) and at least one output thermometer (24) for determining the medium temperature after exit from the electroporator (2), and - a control unit (15) for setting a conveying speed of the transported medium (3) and / or at least one operating parameter of the electroporator (2), wherein an evaluation device (5) for comparing the determined temperature rise with a predetermined target change value and for emitting a warning signal as soon as the difference between the determined temperature rise and the predetermined temperature rise exceeds a limit value, wherein the control unit (15) is designed to adjust at least one operating parameter of the electroporator (2) as a function of the determined conveying speed.

2. The system (1) according to claim 1, wherein the electroporator (2) comprises at least two electrodes (10) which are connected to a pulse generator (14).

3. The system (1) according to any one of claims 1 to 2, further comprising an energy measuring unit (30) for determining the specific energy input into the medium (3) during the treatment with the pulsed electric field.

4. The system (1) according to claim 3, wherein the energy measuring unit (30) determines the specific energy input as a function of the determined conveying speed and operating parameters of the electroporator (2).

5. The system (1) according to any one of claims 1 to 4, wherein the predetermined change target value is calculated according to the following formula: ΔT = W spec c p ∗ f , where Wspec = specific energy input, cp = specific heat capacity of the medium (3) and f = correlation factor.

6. The system (1) according to any one of claims 3 to 5, wherein the energy measuring unit (30) comprises an oscilloscope (31).

7. The system (1) according to any one of claims 1 to 6, further comprising a logging unit (33) for logging operating parameters of the system (1).

8. The system (1) according to any one of claims 1 to 7, further comprising a blocking device (28) for preventing the exit of medium (3) from the system (1) upon output of the warning signal.

9. The system (1) according to any one of claims 1 to 8, further comprising a pressure measuring unit for determining the pressure in the medium (3) after treatment in the electroporator (2).

10. The system (1) according to claim 9, further comprising an overpressure indicator (38) for emitting a warning signal as soon as the determined pressure in the medium (3) exceeds or falls below a predetermined maximum pressure.

11. The system (1) according to any one of claims 1 to 10, further comprising a pH measuring unit for determining the pH of the medium (3) before entering the electroporator (2).