TWI874635B - Container for low temperature storage of agricultural and horticultural crop - Google Patents

Abstract

An object of the present invention is to provide a new container and new packaging and a new preservation method that is suitable for distribution and storage that surely suppresses a significant decrease in the commercial value of agricultural and horticultural crops due to mold, and does not cause odor transfer due to antibacterial active ingredients, coloring or quality deterioration. As a solution, the present invention provides a container for low temperature storage of agricultural and horticultural crop which comprises a sustained release antibacterial film laminated having a base film layer, a volatile antibacterial active ingredient layer containing one or more selected from a group of volatile antibacterial active compounds having a boiling point in the range of 100 to 240 ℃, and a volatile antibacterial active ingredient permeable layer made of vapor deposition polymerized film in this order; and satisfies the following requirements 1 to 3.

[Requirement 1]: The volume of the storage container is 25 cm³ or more and 250,000 cm³ or less.

[Requirement 2]: The area of the sustained release antibacterial film is 1 cm² or more and 5,000 cm² or less.

[Requirement 3]: The ratio of the area of the sustained release antibacterial film (cm²) to the volume of the storage container (cm³) is 0.02 or more.

Description

Containers for low-temperature storage of horticultural crops

The present invention relates to a container for low-temperature storage of horticultural crops with a slow-release antibacterial film, a package containing horticultural crops, and a method for low-temperature storage of horticultural crops.

In the past, there are known methods for long-term preservation of harvested common crops, vegetables, fruits, flowers, mushrooms, etc., such as methods of appropriately inhibiting the respiration of the harvested crops by adding deoxidants, or methods of storing at a freezing temperature below 0°C (for example, Patent Document 1, etc.), but these methods have the problem of being unable to inhibit the occurrence of mold. Domestically, the use of pesticides such as fungicides is not permitted when distributing farm crops, and their use is also greatly restricted in overseas countries such as Europe. Therefore, as for methods for preventing mold in farm crops, there is a known method of sterilizing the harvested farm crops in advance with a hypochlorous acid-based disinfectant, but hypochlorous acid-based disinfectants have problems such as requiring high caution in operation and not being able to achieve long-term effects.

On the other hand, as for methods for imparting antibacterial properties to resin films used for packaging agricultural crops, there are known methods of coating the film surface with a vaporizing antibacterial agent (e.g., Patent Document 2, etc.) or mixing an inorganic antibacterial agent or an organic antibacterial agent into the resin (e.g., Patent Documents 3, 4, etc.). In the former coating method, it is difficult to control the amount of antibacterial agent to be vaporized from the antibacterial film. If the vaporized concentration of the antibacterial agent increases, not only will the smell be transferred to the agricultural crops being packaged, but there is also the risk of causing quality deterioration such as discoloration. In addition, the latter mixing method produces antibacterial activity only in the part of the antibacterial agent that contacts the surface of the exposed antibacterial film, so it is difficult to show antibacterial activity to the entire packaged agricultural and horticultural crops, or the antibacterial agent inside the resin cannot exert antibacterial activity. In order to obtain the desired antibacterial activity, a large amount of antibacterial agent is still required.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 06-046749

[Patent Document 2] Japanese Patent Publication No. 2006-199852

[Patent Document 3] Japanese Patent Publication No. 2016-030406

[Patent Document 4] Japanese Patent Publication No. 2015-189138

The subject of the present invention is to provide a novel container, a novel packaging body, and a novel preservation method, which can effectively inhibit the significant reduction in the commercial value of agricultural and horticultural crops caused by mold, and will not cause taste transfer due to antibacterial active ingredients, nor will it cause quality deterioration such as discoloration, and is suitable for distribution or preservation.

The inventor of the present invention has accumulated research efforts to solve the above-mentioned problems and found that by setting the volume of the storage container and the area of the sustained-release antibacterial film, as well as the ratio of the two within a specific range, it is possible to effectively suppress the significant reduction in the commercial value of agricultural crops caused by mold without reducing the quality of agricultural crops, thereby solving the above-mentioned problems.

Specifically, the present invention is based on the following matters.

1. A container for low-temperature storage of agricultural and horticultural crops, which has a slow-release antibacterial film and meets the following conditions 1 to 3; the slow-release antibacterial film is formed by sequentially stacking the following layers:

Substrate film layer;

The volatile antimicrobial active ingredient layer contains one or more volatile antimicrobial active compounds selected from the group of volatile antimicrobial active compounds with a boiling point in the range of 100 to 240°C;

The volatile antimicrobial active ingredient penetration layer is composed of a vapor-deposited polymer film.

[Condition 1] The volume of the storage container is not less than 25 ^cm3 and not more than 250,000 ^cm3 ;

[Condition 2] The area of the sustained-release antibacterial film is between 1 ^cm2 and 5,000 ^cm2 ;

[Condition 3] The ratio of the area (cm ² ) of the sustained-release antimicrobial film to the volume (cm ³ ) of the storage container is 0.02 or more.

2. A packaging body for storing agricultural crops, which is formed by storing agricultural crops in the low-temperature storage container described in 1.

3. A method for preserving agricultural and horticultural crops, comprising using the preservation container described in 1. to contain the agricultural and horticultural crops and preserving them at a temperature above -3°C and below 15°C.

The sustained-release antibacterial film in the container of the present invention is a volatile antibacterial active ingredient permeation layer formed by a vapor-deposited polymer film, so the specific volatile antibacterial active compound contained in the volatile antibacterial active ingredient layer can be released stably. By setting the volume of the storage container (condition 1) and the area of the sustained-release antibacterial film (condition 2) to a specific range, and setting the ratio of the area to the volume to a specific value or more (condition 3), the amount of volatile antibacterial active ingredients in the storage container can be set to an appropriate amount. The present invention can effectively inhibit the significant reduction in the commercial value of agricultural crops caused by mold without reducing the quality of agricultural crops through such synergistic effects.

Since the volatile antimicrobial active compound with a specific boiling point range used in the present invention is also a plant aroma component used as a food additive, the present invention is useful in terms of being able to safely preserve agricultural and horticultural crops.

Figure 1 is a photograph showing the structures 1 to 4 of the containers used in the storage test in the test 1 of the low-temperature storage of agricultural and horticultural crops in the embodiment.

The following is a detailed description of the low-temperature storage container for agricultural and horticultural crops of the present invention, or the storage method of agricultural and horticultural crops using the container. In addition, the "low temperature" in the present invention refers to a temperature range of above -3°C and below 15°C.

<About horticultural crops>

The low-temperature storage container for agricultural crops of the present invention is a container for storing agricultural crops. Here, the agricultural crops of the present invention refer to all cultivated crops such as common crops, vegetables, fruits, flowers, mushrooms, etc. There is no particular limitation on agricultural crops, but examples include common crops such as rice, wheat, corn, taro, and beans; root vegetables such as radish, carrot, and burdock; stem vegetables such as onion, asparagus, and angelica; leafy vegetables such as cabbage, lettuce, spinach, and Chinese cabbage; fruit vegetables such as tomatoes, eggplants, and pumpkins; cauliflowers such as cauliflower, broccoli, and edible chrysanthemum; fruits such as citrus, apples, pears, grapes, blueberries, strawberries, cherries, and peaches; flowers such as cut flowers; and mushrooms such as mushrooms, matsutake, and maitake.

Among them, from the perspective of being suitable for cold storage and effectively inhibiting mold growth, fruits are suitable as the agricultural and horticultural crops of the present invention, and grapes, cherries, peaches, and strawberries are more suitable. For grapes, cherries, peaches, and strawberries, the temperature range of 0°C or more and 5°C or less is the most suitable storage temperature.

<About volatile antimicrobial active ingredients>

The present invention uses one or more volatile antimicrobial active compounds selected from the group of volatile antimicrobial active compounds having a boiling point in the range of 100 to 240°C as the volatile antimicrobial active ingredient.

The compounds contained in the volatile antibacterial active compound group of the present invention preferably have a carbon atom number of 5 to 10. Specific examples of suitable compounds include hinokitiol (boiling point: 140°C), citronellal (boiling point: 204 to 206°C), chlorophyll (trans-2-hexanal, boiling point: 146°C), citronellol (boiling point: 225°C), geraniol (boiling point: 229°C), nerol (boiling point: 224 to 225°C/745mmHg), etc. Among them, volatile antibacterial active compounds with a boiling point range of 100 to 200°C are preferred, and hinokitiol and chlorophyll are particularly preferred.

The formation of the volatile antimicrobial active ingredient layer of the present invention can be appropriately selected in accordance with the form or properties of the volatile antimicrobial active ingredient used. For example, if the volatile antimicrobial active ingredient is liquid at room temperature, it can be directly applied to one side of the substrate film layer without dilution to form the volatile antimicrobial active ingredient layer. Even if the volatile antimicrobial active ingredient is solid at room temperature or the volatile antimicrobial active ingredient is liquid at room temperature, a solution can be prepared with a predetermined solvent such as ethanol, applied to one side of the substrate film layer, and the solvent can be evaporated to form a volatile antimicrobial active ingredient layer that is substantially composed only of the volatile antimicrobial active ingredient. Alternatively, an evaporation treatment method may be selected, which can vaporize or sublime the volatile antimicrobial active ingredient by heating it, and attach it to one side of the substrate film layer to form a volatile antimicrobial active ingredient layer consisting only of the volatile antimicrobial active ingredient.

The thickness of the volatile antimicrobial active ingredient layer of the present invention can be appropriately determined according to the type of volatile antimicrobial active ingredient selected or the desired duration of antimicrobial activity, but is generally within the range of 1 μm to 5 mm.

<About the penetration layer of volatile antimicrobial active ingredients>

The volatile antimicrobial active ingredient penetrating layer of the present invention is composed of a vapor-deposited polymer film. Here, the vapor-deposited polymer film refers to a film obtained by vapor-deposited polymerization.

Evaporated polymerized films are generally formed by introducing two or more raw material monomers that are vaporized by heating into a film-forming chamber in a vacuum state, and making them adhere to the surface of the film-forming object arranged in the film-forming chamber, and polymerizing the raw material monomers on such a surface. That is, by forming the film while conforming to the fine concave-convex surfaces of the volatile antimicrobial active ingredient layer of the present invention, a volatile antimicrobial active ingredient permeation layer is formed, so that excellent adhesion is exerted between the volatile antimicrobial active ingredient layers and the volatile antimicrobial active ingredient permeation layers. In addition, the evaporated polymerized film can be produced even in an extremely thin film thickness, and the obtained evaporated polymerized film also has the advantage of containing very few impurities. Therefore, the sustained-release antibacterial film of the present invention is between the volatile antibacterial active ingredient layer and the volatile antibacterial active ingredient penetration layer, which advantageously inhibits the occurrence of interlayer peeling caused by hydrolysis or thermal shock, so that the amount of volatile antibacterial active ingredient according to the purpose can be stably released and volatilized.

The synthetic resin constituting the volatile antimicrobial active ingredient permeation layer of the present invention can be appropriately selected according to the volatile antimicrobial active ingredient from among synthetic resins that can form a film according to the conventionally known evaporation polymerization method. Specifically, the synthetic resin film constituting the volatile antimicrobial active ingredient permeation layer can be exemplified by various synthetic resin films that can be produced according to the known evaporation polymerization method, such as polyurea resin film, polyamide resin film, polyimide resin film, polyamideimide resin film, polyester resin film, polyazomethine resin film or polyurethane resin film. Among them, the polyurea resin film can be advantageously used because it has a cross-linked structure that allows the volatile antimicrobial active ingredient to effectively permeate.

In addition, the thickness of the volatile antimicrobial active ingredient penetration layer can be appropriately determined by comprehensively considering the amount of volatile antimicrobial active ingredients released to the outside of the membrane per unit time, or the type or amount of volatile antimicrobial active ingredients contained in the volatile antimicrobial active ingredient layer. Specifically, the thickness of the volatile antimicrobial active ingredient penetration layer is preferably in the range of 0.01μm to 50μm, and more preferably in the range of 0.1μm to 10μm.

<About sustained-release antibacterial film>

The sustained-release antibacterial film of the present invention preferably has a volatile antibacterial active ingredient layer formed on one surface of a substrate film layer, and a volatile antibacterial active ingredient penetration layer composed of a vapor-deposited polymer film is formed on the surface of the volatile antibacterial active ingredient layer. Preferably, the substrate film layer, the volatile antibacterial active ingredient layer and the volatile antibacterial active ingredient penetration layer are approximately the same size.

The sustained-release antibacterial film of the present invention is preferably arranged on the upper part of the container for low-temperature storage of agricultural crops, and more preferably covers the surface of the agricultural crops inside the container, or is arranged on the top of the container by attachment. At this time, it is preferred to arrange the volatile antibacterial active ingredient penetration layer of the sustained-release antibacterial film to face the agricultural crops inside the container.

The container for low-temperature storage of horticultural crops of the present invention is characterized by having a slow-release antibacterial film of 1 cm ² or more and 5,000 cm ² or less as "condition 2". The area of the slow-release antibacterial film is preferably 5 cm ² or more and 1,000 cm ² or less, and more preferably 10 cm ² or more and 500 cm ² or less.

The sustained-release antibacterial film provided in the low-temperature storage container for horticultural crops of the present invention may be used in one piece or in multiple pieces of two or more. When multiple pieces are used, the area of the sustained-release antibacterial film of the present invention means the total area of all the sustained-release antibacterial films used.

<Regarding containers for low-temperature storage of agricultural and horticultural crops>

The container for low-temperature storage of agricultural and horticultural crops of the present invention is made of raw materials such as resin or paper, or in a bag shape, box shape, etc., and is not particularly limited, but the box shape is suitable. However, in order to maintain the amount of volatile antibacterial active ingredients volatilized from the sustained-release antibacterial film of the present invention, a container that can be sealed to a certain degree is preferred.

The low-temperature storage container for agricultural crops of the present invention can be a container composed of the slow-release antibacterial film of the present invention, but the simplest one is to store agricultural crops in a bag-shaped storage container that also includes a raw material different from the slow-release antibacterial film of the present invention, and arrange the slow-release antibacterial film of the present invention on the upper part of the stored agricultural crops, which is also advantageous from the perspective of cost.

The low-temperature storage container for agricultural and horticultural crops of the present invention is characterized in that the volume of the storage container is 25 cm ³ or more and 250,000 cm ³ or less as "condition 1". The volume of the storage container is preferably 500 cm ³ or more and 100,000 cm ³ or less, and more preferably 1000 cm ³ or more and 50,000 cm ³ or less.

<About the amount of volatile antimicrobial active ingredients>

The low-temperature storage container for agricultural and horticultural crops of the present invention can set the amount of volatile antimicrobial active ingredients in the storage container to an appropriate level, so the quality of agricultural and horticultural crops will not be reduced due to taste transfer or discoloration caused by volatile antimicrobial active ingredients, and the obvious reduction in the commercial value of agricultural and horticultural crops caused by mold can be effectively suppressed.

Generally, if a sustained-release antibacterial film is placed in a sealed container, the amount of antibacterial components in the container will increase over time. If the amount of antibacterial components in the container decreases, sufficient antibacterial activity cannot be obtained, and the agricultural crops will completely rot. On the other hand, if the amount of antibacterial components in the container becomes too much, the commodity value of the agricultural crops will decrease due to the taste transfer or discoloration of the volatile antibacterial active components. In other words, in order to effectively inhibit the significant decrease in the commodity value of agricultural crops caused by mold, and to inhibit the taste transfer caused by volatile antibacterial active components, as well as the quality deterioration such as discoloration, the amount of antibacterial components in the storage container must be controlled within an appropriate range.

The present invention can control the amount of antibacterial components in the storage container within an appropriate range, and for the first time identifies the required area of the sustained-release antibacterial film and the volume range of the storage container, as well as the relationship between the sustained-release antibacterial film and the storage container.

The volatile antimicrobial active ingredient in the present invention is one or more selected from the group of volatile antimicrobial active compounds with a boiling point in the range of 100 to 240°C, which is also one of the conditions for setting the amount of the antimicrobial component in the above-mentioned storage container to an appropriate range.

As described above, by setting the amount of volatile antimicrobial active ingredients in the low-temperature storage container for agricultural crops of the present invention to an appropriate range, the low-temperature storage container for agricultural crops can be used, and the low-temperature storage container for agricultural crops can effectively inhibit the significant reduction in the commodity value of agricultural crops caused by mold, and will not cause taste transfer due to antimicrobial active ingredients, nor will it cause quality deterioration such as discoloration, and is suitable for distribution or storage.

In order to set the amount of volatile antimicrobial active ingredients in the low-temperature storage container for agricultural crops of the present invention to an appropriate range, the following conditions 1 to 3 must be met.

[Condition 1] The volume of the storage container is not less than 25 ^cm3 and not more than 250,000 ^cm3 .

[Condition 2] The area of the sustained-release antibacterial film is not less than 1 ^cm2 and not more than 5,000 ^cm2 .

[Condition 3] The ratio of the area (cm ² ) of the sustained-release antimicrobial film to the volume (cm ³ ) of the storage container is 0.02 or more.

Explanation of the above "Condition 3".

"Condition 3" is the ratio of the area (cm ² ) of the sustained-release antimicrobial film to the volume (cm ³ ) of the storage container, that is, the value of the area (cm ² ) of the sustained-release antimicrobial film divided by the volume (cm ³ ) of the storage container is set to be 0.02 or more.

In order to set the amount of volatile antimicrobial active ingredients in the low-temperature storage container for agricultural crops of the present invention to an appropriate range, it is particularly important to satisfy "Condition 3". When the ratio of "Condition 3" is less than 0.02, the amount of volatile antimicrobial active ingredients in the low-temperature storage container for agricultural crops is insufficient, and the anti-mold effect on the agricultural crops in the storage container cannot be obtained. By setting the ratio of "Condition 3" to more than 0.02, a low-temperature storage container for agricultural crops can be obtained. The low-temperature storage container for agricultural crops can effectively inhibit the significant reduction in the commercial value of agricultural crops caused by mold, and will not cause taste transfer due to antimicrobial active ingredients, nor will it cause quality deterioration such as discoloration, and is suitable for distribution or storage.

(Implementation example)

The present invention is described below with reference to embodiments, but the technical scope of the present invention is not limited thereto.

<Preparation of sustained-release antibacterial film>

Using a roll-to-roll evaporation polymerization film forming apparatus, a volatile antimicrobial active ingredient layer was formed on a polyethylene terephthalate (PET) film (thickness: 12 μm) in such a manner that the effective amount of hinokitiol, a volatile antimicrobial active compound, was 1.3 mg/cm ^2. Then, using the same evaporation polymerization film forming apparatus, an evaporation polymerization film composed of a polyurea resin was produced. The evaporation polymerization film composed of a polyurea resin was produced with a thickness of 4 μm.

<Experiment on low temperature storage of horticultural crops 1>

A sealed container 1 with a drain box (capacity: 1,100 cm ³ , bottom size: outer dimension 150 mm×134 mm, height: outer dimension 77 mm) was used as a storage container. As shown in FIG1 , a paper towel soaked with distilled water (20 mL) was laid on the bottom of the storage container, a packaging sponge (FIG1 2 ) was placed in the drain box in a manner that the humidity could be maintained (FIG1 1 ), and a slow-release antibacterial film 1 (area: 78 cm ² ) (FIG1 3 ) was attached to the inner side of the lid of the storage container by double-sided tape. The storage container is used when "Condition 3" in the present invention is about 0.071.

Shine Muscat grapes were used as preserved agricultural crops. As shown in Figure 1, 12 grapes (as shown in Figure 1, No. 4) were placed in a drain box with a packaging sponge, and then sprayed with sterilized water and air-dried for use. This was installed in Figure 1, No. 1, and the lid (Figure 1, No. 3) was sealed, and the preservation test was carried out as Example 1.

The storage container with the only difference being that it does not use a sustained-release antibacterial film was used as Comparative Example 1 and the same storage test was performed.

Observe every week from the beginning of storage to confirm the rotten fruits produced in each test area and calculate their quantity. In addition, rotten fruit particles are removed during observation and confirmation.

The storage test was conducted three times, and the average value of the cumulative spoilage rate (%) was calculated. The test results at a storage temperature of 5°C are summarized in Table 1.

As shown in Table 1, the low-temperature storage container for agricultural and horticultural crops of the present invention (Example 1) has no rotten fruit even after 70 days (2.5 months) from the start of storage, and the average cumulative rotten fruit rate after 91 days (more than 3 months) from the start of storage is 11.1%. In addition, no quality deterioration such as taste transfer or discoloration caused by volatile antibacterial active ingredients was confirmed in the fruit after 91 days from the start of storage. In contrast, when a storage container different from the present invention is used (Comparative Example 1), the average cumulative rotten fruit rate is 8.3% at the point of 21 days (three weeks) from the start of storage, and reaches 69.4% after 91 days (more than 3 months).

That is, by using the low-temperature storage container for horticultural crops of the present invention, it is possible to significantly and effectively inhibit the spoilage of expensive and high-value horticultural crops such as Muscat Royal grapes caused by mold.

On the other hand, although detailed test data are omitted, when the low-temperature storage container for agricultural and horticultural crops of the present invention is used and stored at 20°C, which exceeds the definition of low temperature of the present invention, brown spots appear on the surface of the fruit until the 21st day (three weeks), and then all the fruit grains are confirmed to be spoiled until the 49th day (seven weeks). It is generally believed that this result suggests that even if the low-temperature storage container for agricultural and horticultural crops of the present invention is used, under conditions other than low-temperature storage, the antibacterial active ingredients will cause quality deterioration such as discoloration, which will then promote spoilage.

<Experiment on low temperature storage of horticultural crops 2>

In the same sealed container 1 with a drain box as in the above-mentioned "Experiment 1 on low temperature storage of agricultural and horticultural crops" (capacity: 1,100 cm ³ , bottom size: outer dimension 150 mm×134 mm, height: outer dimension 77 mm), 12 fruit grains and a sustained-release antibacterial film 1 (area: 78 cm ² ) were used. In the same container 2 (capacity: 5,000 cm ³ , bottom size: outer dimension 213 mm×263 mm, height: outer dimension 130 mm), 25 fruit grains and a sustained-release antibacterial film 2 (area: 312 cm ² ) were used and installed in the same manner as in the above-mentioned "Experiment 1 on low temperature storage of agricultural and horticultural crops".

For the preserved horticultural crops, after spraying with a suspension of gray mold fungi (106/mL), air-dried grapes of Muscat au Vie were used to conduct a preservation test at a storage temperature of 5°C. In addition, container 1 (Example 2, Comparative Example 2) used distilled water (20 mL), and container 2 (Example 3, Comparative Example 3) used distilled water (100 mL) to maintain humidity.

Observe every week from the beginning of storage to confirm the rotten fruits produced in each test area and calculate their quantity. In addition, rotten fruits are removed during observation and confirmation.

Example 2 and Comparative Example 2 were subjected to 5 preservation tests, while Example 3 and Comparative Example 3 were subjected to 4 preservation tests. The average value of the cumulative spoiled fruit rate (%) was calculated.

The test results are summarized in Table 2.

The "Experiment 2 on Low Temperature Storage of Horticultural Crops" is a storage test that simulates a very harsh environment of compulsory inoculation with Botrytis cinerea.

As shown in Table 2, in Comparative Example 2, which used a storage container different from that of the present invention, all the test fruit grains were spoiled on the 28th day after the start of storage. Similarly, in Comparative Example 3, which used a storage container different from that of the present invention, 98% of the test fruit grains were spoiled.

On the other hand, even in the storage test under such extremely harsh conditions, in the low-temperature storage container for agricultural crops of the present invention (Examples 2 and 3), the spoilage of agricultural crops caused by mold was kept at less than about 1/5 of the test fruit grains. In particular, in Example 3, the spoilage caused by mold accounted for 6% of the test fruit grains, and the spoilage inhibition effect was obviously excellent. In addition, regardless of the volume of the storage container of "Condition 1", the excellent spoilage inhibition effect was also obviously exerted.

In addition, no quality deterioration such as taste transfer or discoloration due to antibacterial active ingredients was confirmed in the fruit grains of Examples 2 and 3 after 28 days of storage.

<Experiment on low temperature storage of horticultural crops 3>

In a sealed container 1 with a drain box (capacity: 1,100 cm ³ , bottom size: outer dimension 150 mm×134 mm, height: outer dimension 77 mm) similar to the above-mentioned "Experiment 1 on low temperature storage of agricultural crops", 12 fruit grains, sustained-release antibacterial film 1 (area: 78 cm ² ), sustained-release antibacterial film 3 (area: 39 cm ² ), and sustained-release antibacterial film 4 (area: 19 cm ² ) were used and installed in the same manner as the above-mentioned "Experiment 1 on low temperature storage of agricultural crops", and distilled water (20 mL) was used to maintain the humidity.

For the preserved horticultural crops, after spraying with a suspension of gray mold conidia (106/mL), air-dried Muscat Royal grape berries were used for a preservation test at 5°C.

Observe every week from the beginning of storage to confirm the rotten fruits produced in each test area and calculate their quantity. In addition, rotten fruits are removed during observation and confirmation.

The preservation test was carried out 4 times, and the average value of the cumulative spoiled fruit rate (%) was calculated.

The test results are summarized in Table 3.

The "Experiment 3 on low temperature storage of horticultural crops" is a storage test that simulates a very harsh environment of compulsory inoculation with gray mold.

As shown in Table 3, in Comparative Example 5, which used a storage container different from that of the present invention, 97.9% of the tested fruit grains were spoiled on the 28th day after storage.

On the other hand, even in the storage test under such extremely harsh conditions, in the low-temperature storage container for horticultural crops of the present invention (Examples 4 and 5), after 70 days (2.5 months) from the start of storage, the decay of horticultural crops caused by mold only remained below about 30% of the test fruit grains, and the decay inhibition effect was obviously excellent.

On the other hand, Comparative Example 4 is "Condition 3" of the present invention, that is, the ratio of the area (cm ² ) of the sustained-release antimicrobial film to the volume (cm ³ ) of the storage container is about 0.017, which is different from the storage container of the present invention. Therefore, it was confirmed that after the 28th day from the start of storage in Comparative Example 4, the decay of agricultural crops due to mold progressed to about 2.5 to 4 times that of the embodiment.

<Experiments on low temperature storage of horticultural crops 4>

41 fruit grains were placed in a sealed container 3 (capacity: 0.0030m ³ , bottom size: outer dimension 239mm×176mm, height: outer dimension 91mm) with a drain box, and slow-release antibacterial film 5 (area: 233cm ² ) and slow-release antibacterial film 1 (area: 78cm ² ) were used respectively. After spraying with sterilized water (without inoculation) in the same manner as in the above-mentioned "Test 1 on low-temperature storage of horticultural crops", the air-dried fruit grains were subjected to a storage test at the storage temperature shown in Table 4. In addition, container 3 was kept humid with distilled water (60mL).

Observe every week from the beginning of storage to confirm the rotten fruits produced in each test area and calculate their quantity. In addition, rotten fruits are removed during observation and confirmation.

The preservation test was carried out three times and the average value of the cumulative spoiled fruit rate (%) was calculated.

The test results are summarized in Table 4. In addition, the results of Comparative Examples 8 and 9 on the 21st day after the start of storage showed a significant difference from those of Examples 6 and 7, so it was determined that there was no need to continue the test and the test was terminated after observation. "-" in Table 4 means that the test observation was not carried out.

As shown in Table 4, the low-temperature storage container for agricultural crops (Examples 6 and 7) of the present invention has a significantly superior effect in inhibiting the spoilage of agricultural crops caused by mold compared to the storage container (Comparison Examples 6 and 7) different from the present invention in the non-inoculated storage of gray mold fungi simulating the general storage state. In addition, the fruit grains of Examples 6 and 7 after 28 days from the start of storage were not confirmed to have quality deterioration such as taste transfer or discoloration caused by the antibacterial active ingredients.

On the other hand, when stored at 23°C, which is beyond the definition of low temperature of the present invention (Comparative Examples 8 and 9), even if a sustained-release antibacterial film (Comparative Example 8) is used, it is clearly known that the effect of inhibiting spoilage caused by mold cannot be obtained. Furthermore, in Comparative Example 8, discoloration can be observed on about the 10th day after the start of storage. It is generally believed that this result suggests that even if the low-temperature storage container for agricultural and horticultural crops of the present invention is used, under conditions other than low-temperature storage, quality deterioration such as discoloration caused by antibacterial active ingredients will occur, and then promote spoilage.

(Industrial availability)

The sustained-release antibacterial film of the container of the present invention can stably release the specific volatile antibacterial active compounds contained in the volatile antibacterial active component layer because the volatile antibacterial active component permeation layer is formed by a vapor-deposited polymer film. By setting the volume of the storage container (condition 1) and the area of the sustained-release antibacterial film (condition 2) to a specific range, and setting the ratio of the area to the volume to a specific value or more (condition 3), the amount of volatile antibacterial active components in the storage container can be set to an appropriate range. By means of such synergistic effects, the significant reduction in the commercial value of agricultural crops caused by mold can be reliably suppressed without reducing the quality of agricultural crops, which is very useful.

Claims (4)

A box-shaped container for low-temperature storage of agricultural crops, which has a slow-release antibacterial film and a box-shaped container for storage made of a raw material different from the slow-release antibacterial film, and meets the following conditions 1 to 3; the slow-release antibacterial film is formed by laminating the following layers in sequence: a substrate film layer; a volatile antibacterial active ingredient layer containing one or more volatile antibacterial active compounds selected from a group with a boiling point in the range of 100 to 240°C; a volatile antibacterial active ingredient permeation layer composed of a vapor-deposited polymer film; the slow-release antibacterial film is arranged on the upper part of the container for low-temperature storage of agricultural crops; the low temperature is a temperature range of not less than -3°C and not more than 15°C; (Condition 1) the volume of the box-shaped container for storage is not less than 25 ^cm3 and not less than 250,000 cm3 ³ or less; [Condition 2] The area of the sustained-release antimicrobial film is 1 cm ² or more and 5,000 ^{cm 2} or less; [Condition 3] The ratio of the area of the sustained-release antimicrobial film (cm ² ) to the volume of the storage container (cm ³ ) is 0.02 or more and 0.078 or less. The box-shaped container for low-temperature storage of agricultural and horticultural crops as described in claim 1, wherein the slow-release antibacterial film is disposed on the top portion of the box-shaped container for storage. A packaging body for storing agricultural crops, which is formed by storing agricultural crops in the box-shaped container for low-temperature storage described in claim 1. A method for preserving agricultural and horticultural crops, comprising using the box-shaped container for preservation described in claim 1 to contain the agricultural and horticultural crops and preserving them at a temperature above -3°C and below 15°C.