JPH057479A - Method for high-pressure sterilizing treatment - Google Patents

Abstract

PURPOSE:To stably sterilize undried foods, etc., containing a liquid for preservation for a long period under a high pressure with high sterilizing effects by removing oxygen in a packaging container and hermetically sealing the foods in the packaging container in hermetically sealing the foods in the packaging container and carrying out high-pressure sterilizing treatment. CONSTITUTION:Foods, etc., are initially filled in a packaging container and oxygen in the packaging container is subsequently removed to hermetically seal the foods, etc. The foods, etc., hermetically sealed in the packaging container are then subjected to sterilizing treatment under a high pressure of >=1000atm. A well-known vacuum filling device is preferably used to perform vacuum packaging for removing the oxygen in the packaging container and hermetically sealing the foods, etc. Furthermore in the process, the foods, etc., are heated at about 60 deg.C within a range causing no deterioration in quality and vacuum packaging is then preferably carried out due to further improvement in the sterilizing effects.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for high-pressure sterilization of foods, etc., which are filled and sealed in a packaging container, without oxygen.

[0002]

2. Description of the Related Art Conventionally, a packaging container has been filled and sealed,
As a sterilization method for non-dry foods including liquids, 10
The heat sterilization method at about 0 ° C. is widely used. However, in this heat sterilization method, heating by heat conduction takes time, and problems such as destruction of nutritional components and deterioration of taste due to heating occur. In order to solve these problems, an attempt to sterilize foods or the like under high pressure with a liquid pressure of 1000 atm or more has been disclosed in JP-A-59-210873, JP-A-62-69969 and JP-A-01-51040. The effects of high-pressure sterilization treatment have been confirmed in each of these publications.

As a method of filling and sealing foods and the like in a packaging container, in order to prevent rancidity and deterioration of the foods and the like which are contents, the packagings such as a flexible resin film are used for the foods and the like. To seal the air by eliminating the air inside it (so-called vacuum packaging), or by filling food in a packaging container such as paper or plastic or metal that has shape retention, and then removing the air inside. It is common to use a method of substituting with an inert gas (nitrogen, carbon dioxide, water vapor, etc.) and sealing (so-called gas displacement packaging).

[0004]

Recently, as a sterilizing method for non-dried foods containing a liquid for long-term storage, the above-mentioned heat sterilizing method can solve problems such as destruction of nutritional components and deterioration of taste. A high-pressure sterilization treatment method is drawing attention, and a stable high-pressure sterilization treatment method having a high sterilization effect with a pressure as low as possible and a short time is required.

[0005]

In view of the above demand for a high-pressure sterilization treatment method for foods, etc., the inventors of the present invention have conducted extensive studies and as a result, oxygen dissolved in foods has a high pressure. It was discovered that the bactericidal effect in the sterilization treatment was reduced. That is, the present invention eliminates oxygen in a packaging container and seals it by filling food containers and the like in a packaging container and sealing the container, and performing high-pressure sterilization treatment at 1000 atm or more. Residual air in the container is replaced with an inert gas and sealed, and further, by eliminating dissolved oxygen such as foods in the packaging container and sealing, a stable high pressure with high sterilization effect. A sterilization method is provided.

Foods and the like that can be sterilized by the high-pressure sterilization method of the present invention include liquid foods, paste foods, gel foods, etc., or a mixture of these with solid foods, which can transmit pressure. Non-dried (non-hollow) foods containing various liquids can be subjected to high-pressure sterilization without particular restrictions. For example, liquid foods such as juice, milk, liquor, soy sauce, dressing, etc., pasty foods such as mayonnaise, ketchup and jam,
Gelled foods include jelly, pudding, yokan, etc., and mixtures of these with solid foods include potato salad, pickles, fish meat and meat. Also, in addition to foods, for pharmaceuticals such as infusions and drinks,
High pressure sterilization is possible.

Regarding the packaging container that can be used in the high-pressure sterilization method of the present invention, as in the case of the above-mentioned heat sterilization method, a bag-shaped packaging container or the like made of a flexible resin film or the like and a laminate thereof. , A cup-shaped, tray-shaped, or cylindrical packaging container made of paper, plastic, metal, or the like having shape-retaining properties and a laminate thereof, as long as it is a packaging container that can easily transmit pressure and can be sealed. , It can be used without particular restrictions. In this case, despite the high-pressure sterilization treatment of 1000 atm or more, since the liquid, which is a pressure medium described later, and the foods in the packaging container are uniformly pressed, the material strength of the special packaging container is increased. Or, it does not require sealing strength.

In the high-pressure sterilization treatment method of the present invention, 10
As for the high pressure sterilization treatment at 00 atm or higher, the high pressure sterilization treatment can be performed without any particular limitation by using a conventionally known high pressure treatment apparatus as shown in FIG. That is, in a high-pressure processing chamber (10) that can be sealed with a cylindrical pressure-resistant container (11), pressure-resistant lid (16), and pressure piston (12), foods and the like are stored in a packaging container in a sealed state. The pressure medium liquid (usually water)
Are completely filled with the pressure resistant lid (16) so that no air remains in the high pressure processing chamber (10). Next, a hydraulic pump (not shown) normally pressurizes the hydraulic chamber (13) through the hydraulic line (15) to raise the pressurizing piston (12) having a smaller pressurized area than the hydraulic chamber (13). High pressure processing chamber
(10) is pressurized to 1000 to 10,000 atmospheres.

Further, in the high-pressure processing apparatus as shown in FIG. 1, it is usually 200 depending on the kind of bacteria to be sterilized.
High-pressure sterilization treatment is performed at 0 to 7,000 atm for 5 to 120 minutes, but foods etc. that are filled and sealed in a packaging container and a liquid as a pressure medium are preliminarily heated to about 60 ° C and the foods are deteriorated in quality. Heating to no area, hot water conduit (14)
By the high-pressure sterilization treatment while controlling the temperature by means of the hot water jacket (17), it is possible to reduce and shorten the pressurizing pressure and the pressurizing time.

Regarding the method of eliminating oxygen in the packaging container and sealing the packaging container of the present invention, the packaging container such as a flexible resin film is filled with foods and the like, and the air (oxygen 2
This is a so-called vacuum packaging method in which 1% content) is eliminated and sealing is performed, and can be carried out using a conventionally known vacuum filling device without any particular limitation.

The residual air in the packaging container of the present invention is
Regarding the method of substituting with an inert gas and sealing, fill the packaging container such as paper or plastic or metal having shape retention property with foods, etc., and replace the air inside with an inert gas (nitrogen or carbon dioxide gas or This is a so-called gas displacement packaging method in which the gas is replaced with water vapor and sealed, and can be carried out without any particular limitation by using a conventionally known gas displacement filling device.

As the inert gas used in the so-called gas displacement packaging method in the high-pressure sterilization treatment method of the present invention, conventionally known nitrogen gas, carbon dioxide gas, steam or the like can be used. Among them, for nitrogen gas, in order to prevent rancidity and deterioration of the foodstuffs that are the contents, it has been widely used in conventional gas displacement packaging, and nitrogen gas displacement filling devices have also become popular, making it particularly convenient. Can be used.

Further, carbon dioxide used in the so-called gas displacement packaging method has a large amount of dissolution in water,
It is known that carbon dioxide gas 0.88 (gas) is dissolved in water 10.0 (liquid) at a volume ratio of 20 ° C. and normal pressure. In the high-pressure sterilization treatment method of the present invention, the carbon dioxide replacement packaging method has a large amount of dissolved carbon dioxide with respect to water, and therefore, by the high-pressure sterilization treatment, almost all of the carbon dioxide replaced and sealed is a liquid. It will be dissolved in water such as non-dried foods containing it, and the taste of foods etc. will change, and the deformation of the packaging container such as paper and plastic or metal with shape retention will occur. is necessary. That is, the residual air volume to be replaced in the packaging container is reduced (about 20% or less of the content) or replaced with a mixed gas of nitrogen gas and carbon dioxide gas.

Further, regarding steam used in a so-called gas displacement packaging method, in the above-mentioned heat sterilization method, a method in which the air inside is replaced with steam at the same time as the heat sterilization and sealed is widely used. In this case, since the replaced and sealed water vapor (gas) is liquefied and its volume is drastically reduced, in the high-pressure sterilization method of the present invention, deformation of the packaging container such as shape-retaining paper or plastic or metal However, as in the case of carbon dioxide replacement packaging, caution is required such as reducing the residual air volume in the packaging container to be replaced (about 20% or less of the content). Also, as one means of the vacuum packaging method using a packaging container such as a flexible resin film, the steam displacement packaging is convenient (resulting in vacuum It can be used for packaging).

Further, according to the present invention, for the method of eliminating dissolved oxygen such as foods in a packaging container and sealing it, a packaging container such as a flexible resin film or paper having shape retention property or Foods, etc. in a packaging container can be obtained by filling foods, etc. in a packaging container such as plastic or metal, depressurizing and deaeration for a certain period of time, and then sealing by a so-called vacuum packaging method or gas displacement packaging method. It eliminates dissolved oxygen. In other words, the maximum amount of dissolved oxygen of 41.4 mg / L, such as non-dry foods containing liquid, can be reduced to 2.0 mg / L or less by vacuum degassing for about 60 minutes at 30 mmHg using an ordinary vacuum tank. It is a thing.

Further, in the case of the so-called vacuum packaging method or gas displacement packaging method, the contents such as foods are heated in advance to about 60 ° C. within a range where the foods do not deteriorate in quality and decompressed. If vacuum packaging or gas displacement packaging is performed after gas treatment, dissolved oxygen in foods will be effectively eliminated due to a decrease in the amount of dissolved oxygen due to temperature rise. It is possible to further improve the sterilization effect in the high-pressure sterilization treatment by using it together with the sterilization treatment method.

Further, instead of the vacuum packaging method, the gas displacement packaging method and the vacuum degassing treatment, a method of eliminating oxygen in the hermetically sealed packaging container by using an oxygen absorbent or the like can be considered. In addition to the time required for absorption (filling, sealing, and high-pressure sterilization treatment), oxygen absorbers suitable for non-dry foods containing liquids have not yet been developed.

[0018]

【Example】

<Example 1> 10 ml of washed bacterial cell suspension of baker's yeast (Saccharomyces cerevisiae IAM4125) having a bacterial count of 6.0 x 10 ⁷ cells / ml was filled in a bag of stretched nylon / non-stretched polypropylene at 25 ° C. Then, the air in the bag is removed and sealed, and 2 ml of nitrogen, oxygen, and air in the bag, respectively.
Sealing in the presence of (oxygen 21%) was made into 6 bags each to make 4 kinds of test bodies.

Next, a high pressure processing device (MF
P-7000, manufactured by Mitsubishi Heavy Industries KK) was used to perform high-pressure sterilization treatment for 15 seconds at 3000 atm with water at 20 ° C as the pressure medium for each of 3 bags of 4 types of test specimens, and the remaining 4 types. Similarly, three bags of each of the test bodies were similarly subjected to high-pressure sterilization treatment at 3000 atm for 5 minutes, and then the number of surviving bacteria was measured by the pour method. Survival count (average of 3 bags, cells / ml) and bactericidal effect (lo
The number of surviving bacteria / 6.0 × 10 ⁷ is shown in Table 1.

[0020]

[Table 1]

That is, in Example 1, when high pressure sterilization treatment was performed at 3000 atm for 15 seconds using water at 20 ° C. as a pressure medium, oxygen or air (containing 21% oxygen) was present in the packaging container. And the case where air is removed (so-called vacuum packaging) or replaced with nitrogen (so-called gas substitution packaging), there is a clear difference in the high-pressure sterilization treatment effect (1.5 digits, about 30 digits).
) Was recognized. Further, in the high-pressure sterilization treatment for 5 minutes at 3000 atm, which is a normal high-pressure sterilization treatment condition for baker's yeast, when the air in the packaging container is eliminated or replaced with nitrogen, surviving bacteria cannot be detected and completely. It has been sterilized, but when oxygen or air is present, it has about 4 digits (10
Although there was a bactericidal effect of about 000 times), a considerable number of surviving bacteria were detected.

<Example 2> 10 ml of a washed bacterial cell suspension of baker's yeast (Saccharomyces cerevisiae IAM4125) having a bacterial count of 1.6 × 10 ⁸ cells / ml was treated with stretched nylon / non-stretched polypropylene at 25 ° C. Fill the bag with 2.0 ml, 1.0 ml, 0.5 ml, 0.25 ml, and 0.0 ml of oxygen in each bag, and fill the bag with nitrogen so that the total amount becomes 2.0 ml. The thus sealed ones were made into three bags, and five types of test bodies were prepared.

Next, a high pressure processing device (MF
P-7000, manufactured by Mitsubishi Heavy Industries KK), 3 bags each of 5 types of test specimens were subjected to high pressure sterilization treatment at 3000 atm for 60 seconds using water at 20 ° C as a pressure medium, and then the pour method was used. The number of surviving bacteria was measured by. Number of surviving bacteria (average of 3 bags, cells / m
l) and bactericidal effect (log surviving bacteria / 1.6 × 10 ⁸ ) are shown in Table 2.
It was shown to.

[0024]

[Table 2]

In Example 2, the relationship between the amount of oxygen present and the bactericidal effect was verified. In other words, for baker's yeast, which is relatively easy to sterilize under high pressure, the pressurization time was shortened (5 minutes to 60 seconds) compared to the above-mentioned normal conditions for high-pressure sterilization, and the relationship between the amount of oxygen present and the sterilization effect was verified. However, a clear difference (substantially inversely proportional relationship) was observed in the high-pressure sterilization treatment effect.

<Example 3> Bacillus natto (B
acillus subtilis var.niger) bacterial spores 1.0 x 10
Suspend in normal broth medium at ⁴ cells / ml, and fill the bag of stretched nylon / non-stretched polypropylene with 10 ml of suspended medium at 60 ° C. 5 kinds of 3 bags each made by sealing nitrogen in the presence of 0.0 ml, 0.5 ml, 0.25 ml, and 0.0 ml of oxygen and sealing the total amount to 2.0 ml Was used as a test body.

Next, a high pressure processing device (MF
P-7000, manufactured by Mitsubishi Heavy Industries KK), 3 bags each of 5 types of test specimens were subjected to high-pressure sterilization treatment at 5000 atm for 10 minutes using water at 60 ° C as a pressure medium, and then the pour-in method The number of surviving bacteria was measured by. Number of surviving bacteria (average of 3 bags, cells / m
l) and bactericidal effect (log surviving bacteria / 1.0 × 10 ⁴ ) are shown in Table 3.
It was shown to.

[0028]

[Table 3]

In the third embodiment, as in the second embodiment,
This proves the relationship between the amount of oxygen present and the bactericidal effect.
That is, with respect to the bacterial spores of Bacillus natto which is relatively difficult to sterilize under high pressure, an attempt was made to perform high-pressure sterilization treatment with heating at about 60 ° C. described in the section of Means, depending on the amount of oxygen present as in Example 2. A clear difference (substantially inverse proportional relationship) was observed in the high-pressure sterilization treatment effect.

<Example 4> 10 ml of washed bacterial cell suspension of baker's yeast (Saccharomyces cerevisiae IAM4125) having a bacterial count of 3.9 × 10 ⁷ cells / ml was prepared at 25 ° C. by using stretched nylon / non-stretched polypropylene. A bag that is filled in a bag and sealed by removing air from the bag without performing degassing under reduced pressure, and 3
Twelve bags each were prepared by performing vacuum deaeration treatment at 0 mmHg for 60 minutes to eliminate air in the bags and sealing, to obtain two types of test bodies. The dissolved oxygen content in the washed bacterial cell suspension after sealing was 7.5 mg / L on average and 0.5 mg / L on average, respectively.

Next, a high pressure processing device (MF
P-7000, manufactured by Mitsubishi Heavy Industries KK), using 3 bags each of 2 types of test specimens, using water at 20 ° C as the pressure medium, 3000
After performing high-pressure sterilization treatment at atmospheric pressure for 15 seconds, 30 seconds, 45 seconds, and 60 seconds, respectively, the number of surviving bacteria was measured by the pour-in method. Table 4 shows the number of surviving bacteria (average value of 3 bags, number / ml) and bactericidal effect (log surviving number of bacteria / 3.9 × 10 ⁷ ).

[0032]

[Table 4]

In Example 4, the relationship between the elimination of dissolved oxygen in the washed cell suspension and the bactericidal effect was demonstrated. That is, for baker's yeast, which is relatively easy to sterilize under high pressure, the pressurization time is shortened and changed (5 minutes to 15 to 60 seconds) compared with the above-mentioned normal high-pressure sterilization treatment conditions to eliminate dissolved oxygen and sterilize effect. Demonstrating the relationship with
By eliminating dissolved oxygen (reducing 7.5 mg / L to 0.5 mg / L), there is a clear difference in the high-pressure sterilization treatment effect (1.1-1.6).
Digits, about 12 to 40 times) were recognized.

[0034]

As shown in the above examples, it is clear that the sterilization effect in the high-pressure sterilization treatment is reduced when oxygen is present in the packaging container filled with foods and the like and sealed. However, in the high-pressure sterilization treatment, the action of oxygen reduces the sterilization effect.
The inventors could not elucidate.

[0035]

EFFECTS OF THE INVENTION As shown in the above Examples, high-pressure sterilization treatment capable of solving problems such as destruction of nutritional components and deterioration of taste in the above-mentioned heat sterilization method such as non-dried foods containing liquid for long-term storage. Regarding the method, the high-pressure sterilization method of the present invention improves the sterilization effect by eliminating or substituting oxygen in the packaging container and by eliminating dissolved oxygen such as foods, pressurizing pressure and pressure. The present invention provides a stable high-pressure sterilization treatment method capable of reducing and shortening the pressure time and having a high sterilization effect.

Regarding the high-pressure sterilization treatment method of the present invention, the conventional so-called vacuum packaging method and gas displacement packaging method are consequently applied to the high-pressure sterilization treatment method.
The above-mentioned foods that can be sterilized, the packaging containers that can be used, or the use of conventionally known vacuum filling devices and gas displacement filling devices can be subjected to high-pressure sterilization as it is, and it is a versatile and convenient high-pressure sterilization process. A method for high pressure sterilization after high pressure sterilization, which is also a feature of the aforementioned vacuum packaging method and gas displacement packaging method, such as non-dry foods containing liquid as a content, which can prevent rancidity and deterioration. Is provided.

[Brief description of drawings]

FIG. 1 is an explanatory view of a conventionally known high-pressure treatment apparatus in a high-pressure sterilization treatment method of 1000 atm or more according to the present invention.

[Explanation of symbols]

10 ... High-pressure processing chamber 11 ... Pressure resistant container 12 ... Pressure piston 13 ... Hydraulic chamber 14 ... Hot water pipeline 15 ... Hydraulic line 16 ... pressure-resistant lid 17… Warm water jacket

Claims (3)

[Claims] 1. A high-pressure sterilization method, wherein when packaging food products and the like in a packaging container and sealing the mixture and performing high-pressure sterilization treatment at 1000 atm or higher, oxygen in the packaging container is eliminated and sealing is performed. . 2. The high-pressure sterilization treatment method according to claim 1, wherein the residual air in the packaging container is replaced with an inert gas and sealed. 3. The high-pressure sterilization method according to claim 1, wherein dissolved oxygen of the foods in the packaging container is eliminated and sealed.