JP6293192B2 - Vegetable sterilization method - Google Patents

Description

  The present invention relates to a sterilization method for heating and sterilizing vegetables.

  Edible vegetables sold in stores are shipped after being sterilized in advance because it takes days from harvesting and packaging to delivery to consumers.

  Such a sterilization treatment of vegetables has been performed by appropriately selecting from means such as a chemical sterilization method, a mechanical sterilization method, and a heat sterilization method.

Japanese Patent Laying-Open No. 2015-027275 JP 2001-142737 A

  However, sterilizing drugs such as sodium hypochlorite are used for sterilizing drugs, but since consumers tend to avoid additives in recent years, efforts have been made to minimize the amount used. However, there is a problem that a sufficient bactericidal effect cannot be obtained by simply reducing the sterilizing agent.

  In addition, as a mechanical sterilization method, high-pressure treatment or electromagnetic wave sterilization treatment is used, but there is a problem that the treatment apparatus is expensive and the production cost of the product increases.

  Furthermore, as a heat sterilization treatment method, a method of treating food with hot water at 60 ° C. to 120 ° C. is used. However, discoloration and alteration of the food itself cannot be avoided, and there is a problem of deterioration in quality.

  Then, the vegetable sterilization method according to the present invention as a means for solving the above problems is to immerse a vegetable package in which vegetables are enclosed in a resin container and sealed in heated water at 45 ° C. to 59 ° C., and After 4-6 minutes have passed since the center temperature of the vegetable package reaches the same temperature as the heated water, the vegetable package is taken out of the heated water and then cooled by immersing the vegetable package in running water. It is characterized by.

  The running water may be tap water, and the temperature of the running water is preferably 3 to 25 ° C.

  As the form of vegetables according to the present invention, raw vegetables, pickled vegetables, or vegetable kimchi are suitable. Examples of suitable vegetables include leafy vegetables such as Chinese cabbage and cabbage, cucumbers such as cucumber and eggplant, and root vegetables such as squid and radish.

  As the resin container, for example, a resin box, a resin bottle, or a resin bag can be used. Since the resin container can prevent the heated water and the running water for cooling from entering the inside of the container, cross contamination after sterilization can be prevented. The resin container is more preferably a resin bag made of a resin material such as polyethylene (PE) or polypropylene (PP). By using the resin bag body, various bacteria in the air can be discharged in advance by exhausting the air remaining after the vegetables are put inside. Furthermore, if it is a resin-made bag body which exhausted the internal air after putting vegetables into the inside, the heating by heating water and the cooling by the flowing water for cooling can be performed quickly, and time reduction can be aimed at.

  Moreover, the said vegetable package is preferable even if the shelf life improver containing sodium acetate, sodium citrate, and glacial acetic acid is enclosed in the said resin container and sealed with the said vegetable.

  The temperature of the heated water is more preferably 45 ° C to 55 ° C, and further preferably 49 ° C to 51 ° C. This is because by performing sterilization at 49 ° C. to 51 ° C., the effect of improving the elasticity of the sterilized vegetables when chewing the vegetables is obtained as compared to before sterilization.

  The vegetables cooled by running water are preferably stored in a refrigerator at 3 to 8 ° C. in the state of vegetable packaging. It is because the state after vegetables are sterilized can be maintained.

  ADVANTAGE OF THE INVENTION According to this invention, even if it does not use the chemical | medical agent for disinfection, it can implement | achieve the disinfection process of the vegetable which has the effect of extending a shelf life, without producing discoloration to vegetables with cheap capital investment.

  In addition, by encapsulating the shelf life improver in a resin container, the synergistic effect with the shelf life enhancer has the effect of extending the shelf life of the vegetables in a superimposed manner than when only the sterilization method according to the present invention is applied. Obtained.

  In addition, since the heat treatment temperature is lower than the conventional temperature, the heat treatment cost can be reduced.

<Effectiveness verification of the sterilization method according to the present invention using light pickled Chinese cabbage>
In this example, for the verification of the effect of the sterilization method, a shallow pickle made with Chinese cabbage was used as a test sample. Although the present invention can also be used for raw vegetables, it is sufficient to verify the bactericidal effect on bacteria attached to the vegetable surface, whereas processed vegetables such as shallow pickles have fungi inside the vegetables. Since there is a risk of intrusion, the effect of the present invention was verified by verifying the change over time in the number of viable bacteria in the processed vegetables. The pickles were prepared by the following method.
[Manufacturing and processing method of light pickles]
Treatment 1-1 Salting process Place the washed Chinese cabbage, half the weight of the Chinese cabbage, and 2.5 parts by weight of salt with respect to a total weight of 100 parts by weight of the Chinese cabbage and water. After sealing, leave it overnight in a general refrigerator (internal temperature of about 3-8 ° C.).
Process 1-2 Seasoning Process After draining the Chinese cabbage after the salting process, a heavy stone was placed on the Chinese cabbage and pressed. The pressing was performed so that the weight of Chinese cabbage was 50-60% of the weight before pressing. Thereafter, a seasoning liquid having a weight of 1/5 to 1/4 of the weight of cabbage after pressing was added to the Chinese cabbage. As the seasoning liquid, a composition mainly composed of water, brewed vinegar, reduced starch saccharified product, salt and amino acid was used.
Process 1-3 shelf life improver addition process "A shelf life improver" corresponding to 0.3% of the total weight of the cabbage after pressing and the added seasoning liquid is added to the cabbage in the container, and a test sample Asahi pickles were made. The shelf life enhancer contains sodium acetate, sodium citrate, and glacial acetic acid.
Process 1-4 Packaging Process Step As for pickles, the bag was sealed and used as a vegetable package 1 after enclosing it in a transparent thin bag made of PE.
Process 1-5 Heat sterilization process The water tank which stored the heated water which was 49 to 51 degreeC was prepared, and the said vegetable package 1 was immersed in heated water.
After the center temperature of the vegetable package 1 reached the temperature of the heated water, the immersion state was continued for another 5 minutes, and then the vegetable package 1 was taken out from the heated water. The vegetable package 1 taken out from the heated water was immediately immersed in another cooling water tank in which tap water was continuously flowed, and cooled for a sufficient time. For the center temperature of the vegetable package 1, insert a thermometer into the center of the vegetable package 1 created under the same conditions as the test sample, and visually check the temperature displayed on the display of the thermometer It was measured (hereinafter the same in this example).

[Test sample]
Table 1 shows the test samples made of lightly pickled Chinese cabbage used in this verification and the processing contents applied to each test sample in correspondence with ○ marks.

〔Inspection method〕
The general viable count (hereinafter also referred to as viable count) for the obtained test sample was measured according to the plate method in accordance with the food hygiene inspection guidelines. The test was conducted on the 5th and 7th days, based on the time when the number of viable bacteria in the test sample stored at 10 ° C. was measured on the 0th day, immediately after the test sample was prepared. Measurements were made on the 10th, 11th, 12th, 14th, and 15th days.

  Regarding the results obtained, the determination of the bactericidal effect is carried out during the period in which the number of general viable bacteria detected from the test sample is maintained at 100,000 / g or less, which is set as a raw food standard in Japan. The shelf life of the sample was used, and the length of the shelf life was compared.

〔Inspection results〕
About the number of viable bacteria for the light pickled Chinese cabbage sterilized by the sterilization method according to the present invention obtained in the section of “Inspection method” (Examples 1 and 2), the result of measurement along the elapsed time after sterilization It shows in Table 2. For comparison, the viable cell counts for Comparative Examples 1 and 2 that have not been heat sterilized by the sterilization method according to the present invention are also shown in Table 2 after measuring the elapsed time after the packaging step together with the examples.

  The numerical value representing the number of viable bacteria in the table represents the logarithmic value of the number of bacteria. For example, “5.0” represents the fifth power of 10, that is, 100,000 / g (hereinafter the same). Moreover, the notation of “over 5.0” in the table indicates that the number of viable bacteria detected from the test sample is a value exceeding 100,000 / g.

  From the results of Table 2, in Comparative Example 1 in which neither the shelf-life improver addition step (treatment 1-3) nor the heat sterilization step (treatment 1-5) was performed, the viable cell count was 100,000 until the seventh day. The number of viable bacteria exceeded 100,000 / g after the 10th day. On the other hand, in Example 1 to which the heat sterilization step (treatment 1-5) was added, the viable cell count was maintained at 100,000 / g or less until the 12th day.

  Further, in Comparative Example 2 in which the shelf life improving agent addition process (Processing 1-3) was performed but the heat sterilization process (Processing 1-5) was not performed, the number of viable bacteria was 100,000 cells / g or less until the 12th day. And the viable count exceeded 100,000 cells / g after the 15th day, while both the shelf life improver addition step (treatment 1-3) and the heat sterilization step (treatment 1-5) In Example 2 performed, the viable cell count was maintained at 100,000 cells / g or less until the 15th day.

  Moreover, when the test sample of Examples 1 and 2 was compared with the color tone and texture immediately after the heat sterilization step as compared with those before the heat sterilization step, no change was observed. In addition, about the change of a color tone, since the food changed by heating changes to the whited color visually, it was judged by whether such whitening was able to be confirmed visually. In addition, the food texture was judged by whether or not a change in the texture was caused by actually tasting the test sample before and after the heat sterilization process.

  From the results in Table 2, it was found that if the heat sterilization method according to the present invention was used, the effect of extending the best-tasting period of Chinese cabbage for 3 to 5 days was obtained. This effect was equivalent to the effect obtained when the shelf life improver was added. Furthermore, since the effect of the heat sterilization method is exhibited regardless of the presence or absence of the shelf life improving agent, the combined use with the shelf life improving agent can extend the shelf life for 8 days.

<Effect verification of the sterilization method according to the present invention using Chinese cabbage kimchi>
In this example, kimchi produced using Chinese cabbage was used for verification of the effect of the sterilization method. Kimchi was produced by the following method.
[Manufacturing and processing kimchi]
Treatment 2-1 Salting process Place the washed Chinese cabbage, half the weight of the Chinese cabbage, and 2.5 parts by weight of salt with respect to the total weight of the Chinese cabbage and water of 100 parts by weight. After sealing, leave it overnight in a general refrigerator (internal temperature of about 3-8 ° C.).
Process 2-2 Seasoning process After the Chinese cabbage after the salting process was drained, a heavy stone was placed on the Chinese cabbage and pressed. The pressing was performed so that the weight of Chinese cabbage was 50-60% of the weight before pressing. Thereafter, a seasoning liquid having a weight of 1/5 to 1/4 of the weight of cabbage after pressing was added to the Chinese cabbage. As the seasoning liquid, water, isomerized liquid sugar, chili, garlic, salt, brewed vinegar, soy sauce, ginger, amino acid, thickening polysaccharide, and acidulant were mainly used.
Treatment 2-3 shelf life improver addition process “weight shelf life improver” having the same composition as used in treatment 1-3 in “Manufacturing and treatment method of shallow pickles” An amount of 0.3% by weight based on the total weight was added to the Chinese cabbage in the container to prepare a soaked pickle as a test sample.
Process 2-4 Packaging process step After pickling was enclosed in a transparent thin bag made of PE, the bag was sealed and used as a vegetable package 2.
Process 2-5 Heat sterilization process The water tank which stored the heated water which was 49 to 51 degreeC was prepared, and the said vegetable package 2 was immersed in heated water.
After the center temperature of the vegetable package 2 reached the temperature of the heated water, the immersion state was further continued for 5 minutes, and then the vegetable package 2 was taken out from the heated water. The vegetable package 2 taken out from the heated water was immediately immersed in another cooling water tank in which tap water was continuously flowed, and cooled for a sufficient time.

[Test sample]
Table 3 shows the test samples made of Chinese cabbage kimchi used in this verification and the processing contents applied to each test sample in correspondence with circles.

〔Inspection method〕
The general viable cell count (hereinafter also referred to as the viable cell count) for the obtained test sample was measured according to the “inspection method” in the above “verification of the effect of the sterilization method according to the present invention using the cabbage pickled in Chinese cabbage”. The test was conducted on the 5th and 7th days, based on the time when the number of viable bacteria in the test sample stored at 10 ° C. was measured on the 0th day, immediately after the test sample was prepared. Measurements were made on the 10th, 11th, 12th, 13th, 14th, and 15th days.

〔Inspection results〕
Table 4 shows the results obtained by measuring the number of viable bacteria for Examples 3 and 4 sterilized by the sterilization method according to the present invention obtained in the section “Testing Method” along the elapsed time after sterilization. For comparison, the number of viable bacteria for Comparative Examples 3 and 4 that were not heat-sterilized by the sterilization method according to the present invention was also measured by measuring the elapsed time after the packaging step together with the examples, and is shown in Table 4.

  From the results shown in Table 4, in Comparative Example 3 in which neither the shelf-life improving agent addition step (treatment 2-3) nor the heat sterilization step (treatment 2-5) was performed, the number of viable bacteria was 100,000 until the seventh day. The number of viable bacteria exceeded 100,000 / g after the 10th day. On the other hand, in Example 3 which performed the heat sterilization process (process 2-5), the viable cell count maintained 100,000 pieces / g or less until the 12th day.

  Further, in Comparative Example 4 in which the shelf life improving agent addition process (Processing 2-3) was performed but the heat sterilization process (Processing 2-5) was not performed, the number of viable bacteria was 100,000 / g or less until the 12th day. The viable count exceeded 100,000 cells / g after the 15th day, and both the shelf life improving agent addition process (Process 2-3) and the heat sterilization process (Process 2-5) In Example 4 performed, the viable cell count was maintained at 100,000 cells / g or less until the 15th day.

  Moreover, when the test sample of Examples 3 and 4 was compared with the color tone and texture immediately after the heat sterilization step as compared with those before the heat sterilization step, no change was observed.

  From the results of Table 4, it was found that the use of the heat sterilization method according to the present invention provides an effect of extending the shelf life of the Chinese cabbage kimchi for 3 to 5 days. This effect was equivalent to the effect obtained when the shelf life improver was added. Furthermore, since the effect of the heat sterilization method is exhibited regardless of the presence or absence of the shelf life improving agent, the combined use with the shelf life improving agent can extend the shelf life for 8 days.

  From the results of the above studies on the cabbage of Chinese cabbage and kimchi of Chinese cabbage, it was found that the use of the sterilization method according to the present invention provided an effect of extending the shelf life for 3 to 5 days regardless of the processing conditions of the vegetables.

  Furthermore, in the past, it has been difficult to achieve a vegetable shelf life of 2 weeks without using an expensive sterilization treatment method. However, while using the sterilization method according to the present invention for vegetables, By adding it, a shelf life of 2 weeks or more could be achieved. From such an effect, if a shelf life improving agent is used in addition to the sterilization method of the present invention, it is possible to obtain an effect that vegetables can be supplied to consumers at low cost over a long period of time that is not conventional in the market.

<Verification of color and texture changes for other vegetables>
Next, for vegetables other than Chinese cabbage, shallow pickles were prepared by the above-described treatments 1, 2, 4, and 5, and the sensory change immediately after the heat treatment was verified. For vegetables other than Chinese cabbage, pepper, kaidai radish, cabbage, and radish were used. The results obtained are shown in Table 5. The verification items were the presence or absence of changes in color tone and texture.

  In addition, about the change of a color tone, since the food changed by heating changes to the whited color visually, it was judged by whether such whitening was able to be confirmed visually. In addition, the food texture was judged by whether or not a change in the texture was caused by actually tasting the test sample before and after the heat sterilization process.

  From the results of Table 5, not only Chinese cabbage but also other vegetables, there was no change in color tone and texture before and after the heat sterilization treatment.

<Verification of effect of sterilization method according to the present invention using raw vegetables>
In this example, sliced pepper and radish were used for verification of the effect of the sterilization method. Raw vegetables were processed by the method shown below.
[Method of processing raw vegetables]
Process 3-1 Packaging Process After the raw vegetables were sealed in a bag made of PE, the bag was sealed to obtain a vegetable package 3.
Treatment 3-2 Heat Sterilization Step A water tank storing heated water at 49 ° C. to 51 ° C. was prepared, and the vegetable package 3 was immersed in the heated water.
After the center temperature of the vegetable package 3 reached the temperature of the heated water, the immersion state was continued for another 5 minutes, and then the vegetable package 3 was taken out from the heated water. The vegetable package 3 taken out from the heated water was immediately immersed in another cooling water tank in which tap water was continuously flowed, and cooled for a sufficient time.

[Test sample]
Table 6 shows the treatment contents applied to each test sample with ○ marks for the test sample sliced from the raw vegetable pepper used in this verification and the test sample sliced from the radish of the raw vegetable. It shows what was done.

〔Inspection method〕
The general viable cell count (hereinafter also referred to as the viable cell count) for the obtained test sample was measured according to the “inspection method” in the above “verification of the effect of the sterilization method according to the present invention using the cabbage pickled in Chinese cabbage”. The inspection was performed immediately after the treatment was applied to the test sample.

〔Inspection results〕
Table 7 shows the results of the viable cell counts for Examples 5 and 6 sterilized by the sterilization method according to the present invention obtained in the section of “Inspection Method”. For comparison, the number of viable bacteria for Comparative Examples 5 and 6 that have not been heat sterilized by the sterilization method according to the present invention was also measured together with the above Examples and shown in Table 7.

  From the result of Table 7 (1), compared to Comparative Example 5 in which the heat sterilization step (Process 3-2) was not performed on the pepper slice, from Example 5 in which the heat sterilization step (Process 3-2) was performed. It was found that the number of viable bacteria detected was reduced to about 1/10.

  Moreover, compared with the comparative example 6 which did not perform the heat sterilization process (process 3-2) also about the radish slice from the result of Table 7 (2), implementation which performed the heat sterilization process (process 3-2) It was found that the number of viable bacteria detected from Example 6 decreased to 1/10 or less.

  From these results, it was found that the sterilization method according to the present invention has a sterilizing effect on raw vegetables. Moreover, when the test sample of Examples 5 and 6 was compared with the color tone and texture immediately after the heat sterilization step as compared with those before the heat sterilization step, no change was observed.

<Verification of color and texture changes for foods other than vegetables>
Next, about the comparative foods other than vegetables, the packaging process shown below and heat processing were performed, and the sensory change before and behind heat processing was verified. As comparative foods, chicken breast, pork belly, squid somen and Hachimachi sashimi were used. Table 8 shows the obtained results. The verification item was the presence or absence of a change in color tone.
[Method of processing comparative food]
Process 4-1 Packaging Process Step After the comparative food was sealed in a bag made of PE, the bag was sealed to obtain a comparative food package.
Process 4-2 Heat Sterilization Step A water tank storing heated water at 46 ° C. was prepared, and the packaged comparative food package was immersed in heated water.
After the center temperature of the comparative food package reached the temperature of the heated water, the immersion state was continued for another 5 minutes, and then the comparative food package was removed from the heated water. The comparative food package taken out from the heated water was immediately immersed in another cooling water tank in which tap water was continuously flowed, and cooled for a sufficient time.

  From the result of Table 8, about comparative foods other than vegetables, a change appeared in the color tone before and after the heat sterilization process, and all the foods turned white.

  From the above, it has been found that according to the sterilization method of the present invention, sterilization can be performed without causing quality deterioration of vegetables.

Furthermore, even without using a shelf-life improver, it was possible to obtain the same shelf life extension effect as a shelf-life improver. Can be provided. Moreover, by using together with a shelf life improving agent, the preservative and the effect of extending the shelf life by the sterilization method according to the present invention can be added to the vegetable in a superimposed manner, and a vegetable that requires a longer shelf life is provided. It is also possible.

Claims (2)

The vegetable package formed by sealing the vegetable in a resin container is immersed in heated water at 45 ° C to 59 ° C,
After the vegetable package is taken out from the heated water when 4 to 6 minutes have elapsed since the center temperature of the vegetable package has reached the same temperature as the heated water,
A vegetable sterilization method comprising cooling the vegetable package by immersing it in running water. The temperature of the said heating water is 49 to 51 degreeC, The sterilization method of the vegetable of Claim 1 characterized by the above-mentioned.