JP3959963B2 - Sterilization method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention is used for sterilization of various containers, foods filled in the containers, medical instruments, and other instruments (hereinafter referred to as containers).Sterilization methodIn particular, while intermittently carrying the container or the like into the chamber, high temperature and high pressure steam is supplied into the chamber for heat sterilization.On how to do.
[0002]
[Prior art]
[Example of food package]
  As a container that needs to be sterilized by a sterilizer, there is a so-called retort food. This is manufactured by filling a container with food such as cooked rice and then sterilizing and sealing the food under a high temperature condition of about 130 ° C.
  FIG. 8 shows an example of a retort food that is filled with cooked rice and sterilized and sealed. In this retort food 1, the washed rice is filled in a tray 3 that is a container, the tray 3 is sterilized by steam in a sealed chamber (not shown) under high temperature and high pressure conditions, and then the cooking water is poured. After the rice is cooked, the lid 2 is adhered to the tray 3 and sealed.
[0003]
[Specific example of sterilizer]
  FIG. 9 shows a food sterilization apparatus described in Japanese Patent Laid-Open No. 10-99061 according to an example of a sterilization apparatus for sterilizing retort food as described above with high-temperature and high-pressure steam.
  The food sterilizer 10 includes a chamber 11 in which the tray 3 is stored, an air supply pipe 12 that supplies steam to the chamber 11, and a steam generator (not shown) that supplies steam to the chamber 11 through the air supply pipe 12. And an exhaust pipe 13 for exhausting steam from the chamber 11.
  The steam supplied to the chamber 11 via the air supply pipe 12 is always maintained so as to have a steam pressure of 0.3 to 0.35 MPa.
[0004]
  The chamber 11 has an upper chamber 11a and a lower chamber 11b that can be freely opened and closed, and a closed space is formed by closing the upper chamber 11a and the lower chamber 11b.
  The upper chamber 11a is connected to an air supply pipe 12 having an air supply valve 15 that is an electromagnetic valve. When the air supply valve 15 is opened, steam of a predetermined pressure is sent from the air supply pipe 12 to the upper chamber 11a.
[0005]
  The upper chamber 11a is connected to an exhaust pipe 13 having an exhaust valve 16 that is an electromagnetic valve. When the exhaust valve 16 is opened, the vapor filled in the chamber 11 is discharged out of the chamber 11 through the exhaust pipe 13.
  Although not shown, one or more temperature sensors are provided in the chamber 11 to detect the temperature of the vapor in the chamber 11.
[0006]
  Before starting the sterilization process by the food sterilization apparatus 10, the operator determines the timing for starting the sterilization process. The operator opens the supply valve 15 to supply steam into the chamber 11, then closes the exhaust valve 16, and confirms the detection result of the temperature sensor after a predetermined time has elapsed. This operation is repeated while the tray 3 is intermittently carried into the chamber 11, and the temperature detection result by the temperature sensor for each cycle (the period from when the tray 3 is carried into the chamber 11 until it is carried out is one cycle). Confirm.
[0007]
  The temperature in the chamber 11 gradually begins to rise with each cycle, and the tray 3 is carried in, the upper and lower chambers 11a and 11b are closed, the air supply valve 15 is opened, the steam is supplied, the exhaust valve 16 is closed, the predetermined time is maintained, and the air is supplied. The cycle of opening the valve 15, closing the exhaust valve 16, opening the upper and lower chambers 11 a and 11 b, and unloading the tray 3 is repeated several times, and the time when the temperature of the vapor in the chamber 11 is stabilized within the temperature range necessary for sterilization to decide. At this time, the state of the steam (drain) exhausted from the exhaust valve 16 is checked to check whether the steam in the chamber 11 is in a saturated state.
  Then, when the temperature in the chamber 11 and the state of the steam meet the above conditions, the operator starts the sterilization process.
[0008]
  By the way, the chamber 11 has a certain volume to sterilize several retort foods 1 at the same time, and high-temperature steam supplied from one or a plurality of supply pipes 12 A member such as a baffle plate is disposed at an appropriate location so as to spread appropriately within the frame 11.
  However, since the shape in the chamber 11 is complicated and there are a plurality of retort foods 1 carried into the chamber 11, the flow of the steam supplied to the chamber 11 becomes complicated, and the flow rate of the steam varies in various places. Then, a portion having a low temperature called a cold spot may be generated in a part of the chamber 11. Since such a cold spot may adversely affect the reliability of the sterilization process, it is desirable to perform the sterilization process in a state where no cold spot exists.
[0009]
  However, since the conventional sterilization apparatus and the sterilization method detect the temperature of the vapor by the temperature sensor arranged at a predetermined location in the chamber 11, the cold spot generated in the portion away from the temperature sensor is detected. Determining existence is not easy.
[0010]
  In addition, as described above, the operator monitors the state of the steam exhausted from the drain at the start of the sterilization treatment, but it is a skilled operator to determine the presence or absence of a cold spot from the state of the steam exhausted from the drain. It is not easy for them. Furthermore, the determination of the timing for starting the sterilization treatment varies depending on the operator.
  Also, when the stop time is short, such as when checking the sterilizer during the sterilization process, the state of the steam exhausted from the drain and the temperature detected by the temperature sensor There is a problem that there is almost no change and it is difficult to determine the presence of a cold spot.
[0011]
[Problems to be solved by the invention]
  The present invention has been made in view of the above-mentioned problems, and it is possible to reliably monitor sterilization processing including the presence or absence of a cold spot even at the start of sterilization processing by the sterilization device or after a short stop of the sterilization device. Can sterilize highly reliable containers, etc.The purpose is to provide a sterilization method.
[0012]
[Means for Solving the Problems]
  The inventor of the present invention pays attention to the fact that when a cold spot is present in the chamber, the amount of heat (enthalpy) of the steam supplied into the chamber is smaller than a specified value, and has a close relationship with this amount of heat. It was found that the presence of a cold spot can be easily determined by detecting the vapor pressure.
[0013]
  Specifically, the invention described in claim 1In a sterilization method in which a container or the like is intermittently carried in and sealed in a chamber and then sterilized by high-temperature and high-pressure steam supplied to the chamber, and then carried out. A detection step for detecting the vapor pressure in the chamber during one cycle; a comparison step for comparing the maximum value of the vapor pressure detected during one cycle with a preset pressure value; and the maximum value of the vapor pressure. When the pressure value exceeds the preset pressure value, the counting step for counting the number of cycles exceeding the preset pressure value, and the start time of the sterilization treatment when the counted number of cycles continues a plurality of times As a method with a judgment process.
  According to this method, it becomes possible for the determination means to automatically determine that the vapor pressure has risen to a stable pressure, and to start the actual operation of the sterilization process automatically.
[0014]
  The present invention also relates to a sterilization method in which a container or the like is intermittently carried in and sealed in a chamber and sterilized by high-temperature and high-pressure steam supplied to the chamber and then carried out. A detection step for detecting the vapor pressure in the chamber during one cycle from the start to unloading, and a comparison step for comparing the maximum value of the vapor pressure detected during one cycle with the maximum value of the previous cycle And a counting step for counting the number of cycles in which the difference between the maximum values of the pressures in both cycles is within a predetermined range, and the start of the sterilization treatment when the counted number of cycles continues a plurality of times And a determination step for determining that it is time .
  According to this method, it is possible to determine whether or not the vapor pressure has reached the vicinity of the saturated vapor pressure from the gradient of the vapor pressure fluctuation.
[0015]
  The present invention also relates to a sterilization method in which a container or the like is intermittently carried in and sealed in a chamber and sterilized by high-temperature and high-pressure steam supplied to the chamber and then carried out. A detection step for detecting the vapor pressure in the chamber during one cycle from the start to the discharge, and a comparison step for comparing the maximum value of the vapor pressure detected during one cycle with the secondary pressure on the pressure supply side; When the number of cycles in which the difference between the pressures falls within a predetermined range is counted, and when the counted number of cycles continues for a plurality of times, it is determined that it is the start time of the sterilization treatment. And a determination step.
  According to this method, the start timing of the sterilization process can be achieved from the difference between the secondary pressure on the steam supply side and the vapor pressure in the chamber.
[0016]
  In the above invention,The pressure and temperature in the chamber are measured, and the presence or absence of a cold spot is determined from the saturated vapor temperature obtained from the pressure and the temperature.It can be a method.
  According to this method, it is possible to easily determine whether or not there is a cold spot in the chamber based on the pressure of the vapor in the chamber and the detected temperature in the chamber, and it is more reliable. The timing of the appropriate sterilization treatment can be determined.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.
  [First embodiment]
  FIG. 1 shows a first embodiment of the present invention.Device for carrying out the sterilization methodIt is the figure of these, It is the figure which cut the sterilizer in the direction orthogonal to the conveyance direction of a container. Since the basic configuration is the same as that of the food sterilization apparatus 10 shown in FIG. 9, the same parts are denoted by the same reference numerals, and detailed description thereof is omitted.
[0018]
  In the chamber 11 of this apparatus, steam is provided between the tray 3 and an air supply port 12 a for supplying steam from the air supply tube 12 to the chamber 11 and an exhaust port 13 a for exhausting the steam to the outside of the chamber 11 through the exhaust tube 13. A diffusion baffle plate 18 is disposed. Four trays 3 are carried into the chamber 11 in one cycle, and these four trays 3 are simultaneously sterilized.
  The lower chamber 11b is provided with a pressure sensor P for detecting the pressure of the steam supplied into the chamber 11 at an appropriate location.
[0019]
  In this embodiment, the vapor pressure in the chamber 11 detected by the pressure sensor P is displayed as a graph on a display unit such as a display (not shown). Based on the display result, the operator can check the presence / absence of cold spots and sterilization processing. Whether to start or not is determined.
  FIG. 2 is a diagram illustrating an example of a graph displayed on a display unit such as the display. In this graph, the vertical axis represents pressure (vapor pressure), and the horizontal axis represents time (for example, the data sampling interval is 0.2 seconds), and one mountain represents one cycle. In this graph, the temperature detection result (shown by a thin line) by a conventional temperature sensor is superimposed on the pressure graph (shown by a thick line) for comparison.
[0020]
  The temperature detected from the temperature sensor has a substantially constant peak temperature from the position of the arrow A in the graph of FIG. Conventionally, on the basis of the position of the arrow A, while monitoring the state of the steam exhausted from the drain, a further trial run was performed for two to three cycles, and a decision was made to start the sterilization process at the arrow B. .
  However, at this stage, the vapor pressure has not yet reached its peak, suggesting that the amount of heat in the chamber 11 is insufficient, that is, a cold spot may exist. Moreover, the judgment of the timing for starting the sterilization treatment varies depending on the operator.
[0021]
  According to the present invention, the pressure in the chamber 11 reaches a peak at arrow C. Further, here, the vapor pressure has reached a substantially defined saturation vapor pressure (this vapor pressure is indicated by XX in FIG. 2). That is, the arrow C indicates that the amount of heat in the chamber 11 is almost sufficient, and the cold spot has almost disappeared. Thereafter, for confirmation, the same processing is performed for a predetermined number of times, for example, two to three cycles, and if the pressure peak value is stable in this continuous cycle, for example, the arrow D in the figure By the way, the start of sterilization treatment is determined.
  As described above, according to the present invention, it is possible to easily predict the presence of the cold spot by the vapor pressure in the chamber 11. In addition, it is possible to eliminate almost any variation in judgment by the operator. Furthermore, as described in the following embodiment, it is possible to automatically determine the start time of the sterilization process.
[0022]
[Second Embodiment]
  Of this second embodimentSterilization methodCompares the maximum value of the vapor pressure in the chamber 11 detected by the pressure sensor P with a preset pressure value (set pressure value), and automatically determines the start time of the sterilization process based on the comparison result. I have to.
  FIG. 3 shows the second embodiment.For carrying out the sterilization method according to the present inventionFIG.
  thisapparatusThe pressure detection unit 21 detects the pressure in the chamber 11 at predetermined intervals (for example, the data sampling interval is 0.2 seconds) from the detection result of the pressure sensor P, and the pressure detected by the pressure detection unit 21 The maximum pressure value is extracted from the pressure in one cycle detected by the display unit 22 such as a display as shown in FIG. 2 and the pressure detection unit 21 and stored in the memory 24 in advance. The set pressure value is compared with the maximum pressure value, and when the maximum pressure value exceeds the set pressure value, the comparison unit 23 outputs a signal, and the signal is output from the comparison unit 23 every cycle. When a signal is output from the comparison unit 23 for each successive cycle, the counter 25 counts the number of times the signal is output, and the counter 25 counts Number of the cement is, when it reaches the preset number (e.g., 3 times), and a determination unit 26 for determining to start sterilized.
[0023]
  In addition, from the chamber 11, a timing signal of one cycle is output to the pressure detection unit 21 and the counter 25 every time the upper chamber 11a and the lower chamber 11b are opened and closed.
  The maximum pressure value for each cycle is compared with a set pressure value preset in the memory 24 by the comparison unit 23. If the maximum pressure value is larger than the set pressure value, the number of times is set once by the counter 25. Be counted. Similarly, in the next cycle, if the maximum pressure value is larger than the set pressure value, the counter 25 adds 1 to the count number and sets it twice. If the maximum pressure value is smaller than the set pressure value in the next cycle, the count number is reset to zero. For example, if the maximum pressure value continuously exceeds the set pressure value in three consecutive cycles, the determination unit 26 outputs a command signal so as to start the sterilization process.
  According to this embodiment, it is possible to automatically determine the timing of the start of the sterilization process and automatically start the sterilization process.
[0024]
[Third embodiment]
  In the second embodiment, the set pressure value preset in the memory 24 is used as a criterion for determining whether or not to start the sterilization process.
  In the third embodiment, the maximum value of the vapor pressure in the chamber 11 detected by the pressure sensor P is compared with the maximum pressure value of the previous cycle, and this difference is within a predetermined range. The number of times that the value falls within the range is counted, and it is determined that the sterilization process is started when the count number reaches a predetermined number (for example, three times) in a continuous cycle.
[0025]
  This third embodimentFor carrying out the sterilization method according to the present inventionThe configuration of is the same as the configuration of the sterilization apparatus shown in the block diagram of FIG.
  When the maximum pressure value in one cycle exceeds a preset reference pressure value, the comparison unit 23 stores the maximum pressure value in the memory 24 as a new set pressure value. In the next cycle, the new set pressure value is compared with the maximum pressure value in the cycle. When the maximum pressure value of the previous cycle and the maximum pressure value of the current cycle are the same or within a preset range, a signal is output to the counter 25. The determination unit 26 determines to start the sterilization process when the count number becomes 3, for example, in a continuous cycle.
  In this embodiment, the lower limit value of the pressure value necessary for the sterilization process may be set in the memory 24 in advance as the reference pressure value. Accordingly, it is possible to start the sterilization process on the precondition that the maximum pressure value exceeds the reference pressure value.
[0026]
[Fourth embodiment]
  In the fourth embodiment, instead of the set pressure value set in the memory 24, the secondary pressure value (for example, the minimum limit value at the peak time) on the steam supply side (the steam generator side in FIG. 9), The maximum pressure value is compared.
  FIG. 4 is a graph showing fluctuations in secondary pressure during one cycle. In FIG. 4, a timing chart for opening and closing the exhaust valve 16 and the air supply valve 15 is shown above the graph.
  When the supply of steam into the chamber 11 is started, the exhaust valve 16 (see FIG. 9) is first opened, and then the air supply valve 15 (see FIG. 9) is opened. While both the exhaust valve 16 and the air supply valve 15 are open, the secondary pressure rapidly decreases from the pressure indicated by symbol I in FIG. 4 to the pressure indicated by symbol II. Thereafter, when the exhaust valve 16 is closed, the pressure in the chamber 11 is increased by the steam supplied from the air supply pipe 12.
[0027]
  At the position indicated by reference numeral III where the vapor pressure in the chamber reaches the saturated vapor pressure, the vapor pressure is substantially stabilized. When one cycle is completed and the air supply valve 15 is closed, the secondary pressure returns to the pressure indicated by the reference symbol IV which is the same level as the reference symbol I again.
  In this embodiment, the secondary pressure (or the minimum limit value of the secondary pressure) indicated by the symbol I or IV is compared with the pressure in the chamber 11 detected by the pressure sensor P, and the sterilization process is performed based on the comparison result. To determine when to start.
  The graph of FIG. 5 shows the relationship between the pressure fluctuation in the chamber 11 and the pressure fluctuation of the secondary pressure in successive cycles. In the graph of FIG. 5, one mountain represents one cycle.
[0028]
  In the graph of FIG. 5, the pressure fluctuation in the chamber 11 is indicated by a thin line, and the pressure fluctuation of the secondary pressure is indicated by a thick line. Then, the difference between the maximum pressure value in the chamber 11 and the minimum limit value of the secondary pressure at the peak (a value indicated by a YY line in the graph of FIG. 5) (Z in the graph of FIG. 5).₁~ Z₆Is determined to be stable within a preset range, and the sterilization start is determined. For example, in the example shown in the graph of FIG.₄Converges within a preset range. Then, another two-cycle test run is performed and the difference Z₄~ Z₆Is almost stable, it is determined to start the sterilization process at 3 in the figure.
  This embodimentFor carrying out the sterilization method according to the present inventionA block diagram of FIG. 6 is shown in FIG.
  Of this sterilizerThe configuration is the same except that the memory 24 of the second and third embodiments is replaced with a memory 28 in which the minimum limit value of the secondary pressure is stored.
[0029]
  That is, the comparison unit 23 compares the maximum pressure value of the vapor in the chamber 11 in one cycle with the minimum limit value of the secondary pressure stored in the memory 28, and the difference between the two values falls within a predetermined range. The signal is output to the counter 25.
  Then, as in the second and third embodiments, the determination unit 26 sterilizes when the count number of the signals continuously output from the comparison unit 23 within a continuous cycle becomes, for example, three times. It is determined to start the process.
[0030]
  In this embodiment, as shown in FIG. 6B, is the supply-side vapor pressure detected by the secondary pressure gauge 27 between the secondary pressure gauge 27 and the comparison unit 23 appropriate? You may provide the secondary pressure monitoring part which monitors whether.
  The secondary pressure monitoring unit includes a memory 28 that stores the minimum limit value of the secondary pressure, and a comparison unit 29 that compares the vapor pressure detected by the secondary pressure gauge 27 with the minimum limit value stored in the memory 28. And a determination unit 30 for determining whether or not the secondary pressure is appropriate based on the comparison result of the comparison unit 29.
  When the secondary pressure becomes lower than the minimum value due to the occurrence of any abnormality, the determination unit 30 outputs the detection result of the secondary pressure gauge 27 to the comparison unit 23 without outputting the detection result. A secondary pressure abnormality alarm that notifies that the secondary pressure is abnormal is output.
  As a result, inconveniences such as defective sterilization due to abnormality on the pressure supply side can be avoided in advance.
[0031]
[Fifth embodiment]
  In the fifth embodiment, in addition to the pressure sensor, a temperature sensor T for detecting the vapor temperature in the chamber is provided.
  FIG. 7 shows this embodiment.For carrying out the sterilization method according to the present inventionThe block diagram of is shown.
  Since the pressure detection unit, the comparison unit, the counter, and the memory are the same as those in the second and third embodiments, the same reference numerals as those in FIG.
[0032]
  This sterilizer isThe temperature sensor T, the temperature detection unit 31, the display unit 32, the comparison unit 33, the memory 34, and the counter 35 are further included.
  The temperature detection unit 31 displays the temperature detected by the temperature sensor T on the display unit 32 such as a display as a graph as shown in FIG. The display unit 32 may be the same as the display unit 22 that displays the pressure detection result. And as shown in FIG. 2, you may make it display the pressure detected by the pressure sensor P, and the temperature detected by the temperature sensor T on one graph.
[0033]
  Further, the temperature detection unit 31 extracts the highest temperature in one cycle from the temperatures detected by the temperature sensor T, and transmits the highest temperature to the comparison unit 33. The comparison unit 33 compares the temperature preset in the memory 34 with the maximum temperature, and outputs a signal to the counter 35 when the maximum temperature exceeds the preset temperature. The counter 35 determines whether or not the signal is output from the comparator 33 every cycle, and counts the number of times the signal is output when the signal is continuously output from the comparator 33 in successive cycles. To do. When the number of continuous outputs of the signal counted by the counter 35 reaches a preset number (for example, 3 times), the determination unit 36 determines to start the sterilization process.
[0034]
  In this case, the determination unit 36 simultaneously determines whether the count number of the signals continuously output from the comparison unit 23 within a continuous cycle is a predetermined number of times, and when the predetermined number has been reached. And outputs a command to start the sterilization process.
  That is, when not only the temperature but also the pressure satisfies a predetermined condition, the determination unit 36 outputs a command to start the sterilization process.
[0035]
  Also in this embodiment, every time the upper chamber 11a and the lower chamber 11b are opened and closed, a one-cycle timing signal is output to the pressure detection unit 21, the counter 25, the temperature detection unit 31, and the counter 35.
  By comprising in this way, the timing of a sterilization start can be aimed from both temperature and vapor pressure, presence of a cold spot can be predicted more reliably, and more reliable sterilization processing can be performed. It becomes possible.
[0036]
  Although preferred embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments.
  For example, in the above embodiment, the sterilization of retort food has been described as an example. However, the present invention can be applied to medical instruments, other containers, and the like.
  The timing signal for one cycle has been described as being detected from the opening / closing timing of the upper chamber 11a and the lower chamber 11b, but the timing signal is output from the transport timing of the tray 3 on a transport device such as a conveyor. It is also possible to do.
[0037]
  Furthermore, in the above description, when the maximum value of the vapor pressure and the maximum value of the temperature exceed a preset temperature, the comparison unit has been described as outputting a signal to the counter. It is also possible to configure so that a signal is output to the counter when a predetermined relationship is reached with respect to a preset value.
  In the above description, the determination unit outputs a command to start the sterilization process when the count number by the counter reaches a plurality of times continuously, but the count number may be one.
[0038]
【The invention's effect】
  Since the present invention is configured as described above, it is possible to easily determine the presence or absence of a cold spot even at the start of the sterilization process of the sterilizer or after a short stop.
  Therefore, the start timing of the sterilization process can be set appropriately to perform a sterilization process of a highly reliable container or the like. In addition, when setting the timing, it is possible to eliminate almost any variation in judgment due to individual differences among workers.
[Brief description of the drawings]
FIG. 1 according to a first embodiment of the present invention.Device for carrying out the sterilization methodIt is the figure of these, It is the figure which cut the sterilizer in the direction orthogonal to the conveyance direction of a container.
FIG. 2 is a diagram illustrating an example of a graph displayed on a display unit.
FIG. 3 is a second embodiment.For carrying out the sterilization method according to the present inventionFIG.
FIG. 4 is a graph showing fluctuations in secondary pressure during one cycle.
FIG. 5 is a graph showing the relationship between the pressure fluctuation in the chamber and the pressure fluctuation of the secondary pressure in a continuous cycle.
6 (a) and 6 (b) show a fourth embodiment.For carrying out the sterilization method according to the present inventionFIG. 6B is a block diagram for explaining the configuration, and FIG. 6B shows a case where a secondary pressure monitoring unit is added to the sterilizer of FIG.
FIG. 7 is a fifth embodiment.For carrying out the sterilization method according to the present inventionIt is a figure which shows these block diagrams.
FIG. 8 is a perspective view showing an example of a retort food that is filled with cooked rice and sterilized and sealed.
FIG. 9 is a diagram showing a food sterilization apparatus described in Japanese Patent Laid-Open No. 10-99061 according to a conventional example of a sterilization apparatus.
[Explanation of symbols]
  1 Retort food
  3 trays
  11 chambers
  11a chamber
  11b Lower chamber
  12 Air supply pipe
  13 Exhaust pipe
  15 Air supply valve
  16 Exhaust valve
  18 Baffle plate
  P Pressure sensor
  T temperature sensor

Claims (4)

In the sterilization method of intermittently carrying in and sealing a container or the like in the chamber, carrying out sterilization treatment with high-temperature and high-pressure steam supplied to the chamber,
  A detection step of detecting the vapor pressure in the chamber during one cycle from loading the container and the like to unloading;
  A comparison step of comparing the maximum value of the vapor pressure detected during one cycle with a preset pressure value;
  When the maximum value of the vapor pressure exceeds the preset pressure value, a counting step that counts the number of cycles that have exceeded,
  A determination step of determining that it is the start time of the sterilization treatment when the counted number of cycles continues a plurality of times;
  The sterilization method characterized by having. In the sterilization method of intermittently carrying in and sealing a container or the like in the chamber, carrying out sterilization treatment with high-temperature and high-pressure steam supplied to the chamber,
  A detection step of detecting the vapor pressure in the chamber during one cycle from loading the container and the like to unloading;
  A comparison step of comparing the maximum value of the vapor pressure detected during one cycle with the maximum value of the previous cycle;
  A counting step of counting the number of cycles in which the difference between the maximum values of the pressures in both cycles is within a predetermined range;
  A determination step of determining that it is the start time of the sterilization treatment when the counted number of cycles continues a plurality of times;
  The sterilization method characterized by having. In the sterilization method of intermittently carrying in and sealing a container or the like in the chamber, carrying out sterilization treatment with high-temperature and high-pressure steam supplied to the chamber,
  A detection step of detecting the vapor pressure in the chamber during one cycle from loading the container and the like to unloading;
  A comparison step of comparing the maximum value of the vapor pressure detected during one cycle with the secondary pressure on the pressure supply side;
  A counting step of counting the number of cycles in which the difference between the two pressures is within a predetermined range;
  A determination step of determining that it is the start time of the sterilization treatment when the counted number of cycles continues a plurality of times;
  The sterilization method characterized by having. The pressure and temperature in a chamber are measured, The presence or absence of a cold spot is judged from the saturated steam temperature calculated | required from the said pressure, and the said temperature, The sterilization method in any one of Claims 1-3 characterized by the above-mentioned.

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