JP2912876B2 - Method for producing aseptic packed cooked rice - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing aseptic packed cooked rice, and more particularly to a method for producing packed cooked rice that can be completely sterilized by substantially completely killing not only general bacteria but also heat-resistant bacteria. About the method.

[0002]

2. Description of the Related Art A so-called retort food is known as a sterile packed food. This is manufactured by filling and sealing a food such as cooked rice in a container and then sterilizing under high temperature and high pressure conditions. It can be completely killed.

However, since heat is gradually transmitted from the periphery to the center of the packed food, when the temperature of the center of the food reaches 130 ° C., the temperature of the surrounding part is considerably higher than that of the packed food. There is a problem that is greatly impaired. In the case of retort sterilization without deteriorating the taste, the temperature in the central portion does not reach the predetermined temperature, so that complete sterilization cannot be realized.

[0004] As described above, it is practically difficult to completely sterilize retort food without losing its taste, and many attempts have been made to realize this by a method other than retort.

[0005] Rice cooking methods conventionally proposed for producing aseptic-packed cooked rice include a multi-shed rice cooker method, an individual cooker rice cooker method, and an individual meal tray cooker method.

[0006] In the multi-tablet rice cooking system, rice is washed and dipped in rice for 5 minutes.
Filled into a 15kg pot, watered, continuously gas cooked and steamed, then unraveled in a clean room, served individually in a UV-sterilized container with a machine, and fitted with a UV-sterilized oxygen scavenger Further, the container is sealed with a UV-sterilized lid. The degree of cleanliness in a clean room requires a class of about 100 to 1,000.

[0007] In the individual rice cooker rice cooking method, rice is washed and immersed rice is filled into a special rice cooker one by one and water is added thereto. Gas cooking and steaming are successively performed, and then loosened in a clean room.
The container is transferred to a UV-sterilized container, a UV-sterilized oxygen scavenger is attached, and the container is sealed with a UV-sterilized lid. Also in this case, the degree of cleanliness in the clean room requires a class of about 100 to 1000.

[0008] In the individual meal tray rice cooking method, rice washed and soaked rice is directly filled in a plastic tray one serving at a time, then sterilized by pressure, then poured into a steam rice cooker, continuously cooked, and subjected to UV sterilization. After sealing with a lid, the container is turned upside down and steamed. After steaming, the container is again turned upside down and the container is discharged from the rice cooker. The process from the outlet of the rice cooker to the hermetic seal is performed in a clean booth with a cleanness of 100 to 1000 class.

[0009]

However, in the multi-tablet rice cooker system and the individual-tablet rice cooker system, many processes are required to be performed in a clean room, and equipment and management for the process are required. In addition, since cleaning or sanitizing is required every time a worker enters or leaves the office at the end of working hours and during working hours, the operation rate is reduced and the product cost is significantly increased.

On the other hand, in the case of the individual-meal tray rice cooking method, it is sufficient to simply provide a clean booth in the process from the rice cooker outlet to the hermetic seal. There are advantages in terms of cost.

However, even in the case of the individual-meal tray rice cooking method, in order to remove oxygen in the container to prevent oxidation of cooked rice and to prevent secondary contamination by aerobic bacteria and mold, an oxygen scavenger is used. (So-called ageless) must be sealed in the container. Further, the container is required to have a gas barrier property, and in order to satisfy the requirement, a relatively expensive eval resin or a polypropylene multilayer must be used, which increases the product cost.

[0012] Further, in any method, general viable bacteria are almost completely killed during rice cooking, but there is no process for treating heat-resistant viable bacteria adhering to raw materials and the like.
It has not been possible by any conventional method to produce completely aseptic packed cooked rice that kills even heat-resistant bacteria.

[0013]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a completely sterilized packed rice cooked by killing not only general bacteria but also heat-resistant bacteria while taking advantage of the conventional individual-meal tray rice cooking method. It is an object to provide a new method that can be manufactured.

That is, the method for producing aseptic packed cooked rice according to the present invention comprises:
For rice filled in individual food trays in a sealed chamber
To intermittently flush high-pressure, high-temperature saturated steam
The rice is pre- sterilized at the same time as the rice is pre-gelatinized, and then cooked water is poured into the cooked rice, and then the individual food tray is covered with a lid and hermetically sealed. For example, 5-1
One cycle of high-pressure, high-temperature saturated vapor flash treatment for 0 seconds
The sterilization process is performed by repeating this process 6 to 8 times.
U. This shortens the sterilization time for rice,
A sufficient sterilizing effect can be obtained without impairing the taste.
Wear.

[0015]

In this case, in order to prevent the rice filled in the tray from being scattered by intermittent flashing of high-pressure, high-temperature saturated steam, the opening of the tray is formed in a closed chamber with a plate having a substantially honeycomb shape. It is preferable to cover with a member.

In the present invention, rice is preferably cooked by a steam rice cooker. This makes it possible to improve the efficiency of the rice cooking process as a rice cooker having a three-dimensional configuration in which a multi-row multi-stage gondola is driven to circulate in a steam chamber.

Further, it is preferable to perform a process from completion of rice cooking to completion of hermetic sealing in a clean booth. The clean booth has a cleanness of about 100 to 000.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A process for producing sterile packed cooked rice according to the present invention is shown in the chart of FIG. 1 and will be described below based on the chart.

Rice (milled rice) milled by a milling machine is stored in a rice storage. The rice is washed and immersed in a conventional manner using degassed water, pre-treated so as to have a water content of about 10 to 30%, and then filled into individual meal trays (containers).

The tray filled with rice in a fixed amount is sent to a closed chamber after being leveled as necessary,
The container and rice are sterilized under high pressure and high temperature conditions. Thereby, not only general living bacteria but also heat-resistant living bacteria can be killed.

Sterilization in a closed chamber is 100
By using pressurized steam at a high temperature of 130 ° C. or higher, preferably 130 ° C. to 140 ° C., it is possible to perform batch processing on a large number of trays housed in a closed chamber within a short time of several tens of seconds. Steam pressure is 2.7-3.0kgf / cm
The pressure is preferably set to about 2 and is press-fitted from a steam generator into a closed chamber.

By performing the sterilization treatment under such high pressure and high temperature conditions, the rice in each tray is pregelatinized, so that subsequent rice cooking can be performed smoothly in a short time.

The sterilization is performed by intermittently flushing the rice filled in the individual food tray with saturated steam of high pressure and high temperature . For example, the high-pressure high-temperature saturated vapor flash treatment for 5 to 10 seconds is repeated about 6 to 8 times as one cycle.

Such an intermittent or intermittent autoclaving treatment enables effective sterilization without impairing the taste of rice, and also during non-treatment intervals without steam flashing. In addition, since the individual food tray can be advanced from the rice filling section to the steam rice cooker, the operation of the production line can be made more efficient and faster.

After the sterilization treatment in the closed chamber, each tray is filled with cooking water in a fixed amount, and then put into a steam rice cooker for steam rice cooking in a conventional manner. In order to improve the texture and the yield, it is preferable to use degassed water for cooking water. Also,
The water or hot water for cooking water may be sterilized in advance, and may be adjusted to a predetermined pH value. In the case of manufacturing packed rice and red rice packs, in addition to filling the cooking water, the necessary seasoning liquid, coloring liquid, ingredients and the like are filled into the tray.

In order to save space, it is preferable to use a circulating multi-row, multi-stage gondola for the steam rice cooker. That is, a plurality (for example, 8) of multi-stage gondolas in which a plurality of (for example, 8) shelves capable of accommodating a plurality of (for example, 8) trays are vertically stacked in parallel at equal intervals. A transport device is installed in which these multi-stage gondola are connected at equal intervals to a chain conveyor that is driven to rotate on a vertical plane. As a tray plate for storing a tray, for example, openings for fitting the main body of the tray are formed in parallel with the number of trays to be stored, and the upper edge of the tray is placed around the opening. Can be used to accommodate the tray.

When such a multi-row multi-stage gondola is used, a tray filled with sterilized rice and cooking water is moved by a transfer device above a steam rice cooker (steam chamber) and returned. It is sent to each stage of the coming empty multi-stage gondola.
Then, the gondola containing the trays in all stages enters the steam chamber and moves for a predetermined time (for example, about 3
0 minutes), steam rice cooking is performed.

The steam chamber can be divided into a plurality of zones, and the temperature can be controlled independently for each zone. Thereby, the optimum steam temperature is set according to the rice cooking process.

The gondola that has finished cooking rice is pulled up by the chain conveyor, and the trays are sent out one by one onto the conveyor. The emptied gondola returns to the entrance of the steam rice cooker and is recycled to the next tray.

Each tray is checked for metal detection while being conveyed by the conveyor after the completion of rice cooking, and defective products in which metal is detected are excluded from the line.

The tray that has passed the metal detection is then transferred to a hermetic sealing machine, where a suitable UV-sterilized lid is applied to the tray to hermetically seal, and cut off unnecessary portions of the sealed lid. Trimming is performed. The trays between the steam rice cooker and the airtight sealing machine are conveyed by the conveyor, but during this time, the seal is sealed from the outlet of the steam rice cooker to prevent secondary contamination due to exposure to the outside air for a short time. The area extending to the machine is installed in a clean booth having a degree of cleanness of about 100 to 1,000.

For example, a tunnel-shaped booth is provided between the outlet of the steam rice cooker and the sealing and sealing machine, and a clean air generator is attached to the upper center of the booth to continuously generate clean air. The booth is maintained at a positive pressure (for example, 0.5 to 2 mmAq higher than the outside pressure), clean air flows from the top to the bottom of the booth, and from the center to the outer periphery. Bacteria can be discharged to the outside by flowing the steam to a steam rice cooker.

The tray may be hermetically sealed after flushing with an inert gas. If necessary, a deoxidizer can be enclosed.

After the tray is hermetically sealed, steaming is carried out for a predetermined time by a conventional method to make the difference in water absorption rate between the upper layer and the lower layer after rice cooking uniform and to promote the pregelatinization. Inverting the hermetically sealed tray prior to the steaming process promotes equalization of the upper and lower moisture levels. After steaming, the tray is passed through a cold water bath and cooled to room temperature. It is preferable to improve the processing efficiency by adopting a multi-stage multi-row gondola similar to the steam rice cooker described above for the steamer and the cooling tank.

After cooling, return the inverted tray to its original
After drying the surface, and printing, pinhole inspection, weight inspection and other post-processing processes such as date of manufacture and expiration date,
It is packed in a predetermined case and shipped.

An analysis test was carried out on the aseptic packed cooked rice produced by the above method by a standard agar plate culture method. As a result, both the number of general bacteria (the number of viable bacteria) and the number of heat-resistant spores were 300 or less, and It was confirmed that it was substantially completely sterilized.

[0038]

According to the present invention, rice washing in a tray is sterilized under high pressure and high temperature conditions in a low moisture state before cooking water is added, so that not only general viable bacteria, Since the heat-resistant viable bacteria that may have adhered to the rice can be completely killed, it is possible to provide a completely sterile packed rice cooked in a true sense.

In the present invention, the encapsulation of an oxygen scavenger and the adjustment of pH, which have been required for the conventional complete sterilization, are basically unnecessary, and the cost can be reduced.

Further, according to the present invention, unlike the case of the conventional retort treatment, it is possible to produce completely sterile packed cooked rice without deteriorating the taste.

[Brief description of the drawings]

FIG. 1 is a chart showing a process for producing aseptic packed cooked rice according to the present invention.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-155121 (JP, A) JP-A-7-111866 (JP, A) JP-A-3-155761 (JP, A) JP-A 9-155 19277 (JP, A) JP-A-3-201954 (JP, A) JP-A-7-194353 (JP, A) JP-A-5-316969 (JP, A) JP-A-2-291237 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) A23L 1/10 B65B 55/06

Claims (3)

(57) [Claims] Claims: 1. A fixed quantity of rice washed and immersed in a single food tray, and the rice filled in a single food tray in a sealed chamber.
Flash high-pressure, high-temperature saturated steam
A method for producing aseptic packed cooked rice, characterized in that the rice is pregelatinized at the same time as the above, and then the rice is pregelatinized, then cooked water is poured into the cooked rice, and the individual food tray is covered with a lid and hermetically sealed. 2. A high-pressure, high-temperature saturated steam flash for 5 to 10 seconds.
The process is repeated six to eight times in one cycle
The method for producing aseptic packed cooked rice according to claim 1, characterized in that: 3. Opening of an individual food tray in a sealed chamber.
Cover the mouth with a plate with holes in a substantially honeycomb shape,
The rice filled in the tray is intermittently
Shattered to prevent scattering
The method for producing aseptic packed cooked rice according to claim 1 or 2.