JPS583667B2 - Hydrothermal food sterilization method and equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot water sterilization method for heating and sterilizing plastic bagged foods to produce so-called retort foods, generally speaking, sterilization of foods using pressurized hot water. Concerning sterilization methods and devices.

Heat sterilization used to be carried out at temperatures below 100℃ for 0.5 to 2 hours, but in recent years heat sterilization has been carried out exclusively at temperatures above 100℃ for 0.5 to 2 hours, but as this harms the flavor and structure of the food and reduces the value of the food. High-speed sterilization using pressurized hot water at 120 to 135°C is mainstream.

In this case, the problem is that the sterilization process is for a short period of time, for example, several minutes, so that even a slight delay in the process time can have a significant impact on the quality of the product.

For example, if there is a time lag in the center temperature of food during processing, there will be unevenness between those that have received sufficient heat and those that have not, resulting in overcooking for one and half-cooked for the other. become.

In such cases, some food must be sacrificed to ensure safety.

However, in conventional hot water treatment, food is placed in a pressure vessel and then hot water is injected with a pump, so it takes a considerable amount of time to fill the pressure vessel with hot water, and the food in the upper and lower parts of the vessel is heated. As mentioned above, there is a drawback that there is a difference in the time of contact with hot water between the two types.

In order to eliminate such problems caused by the time difference in hot water injection, it is better to abandon the time-consuming injection method and adopt a method in which food is directly immersed in hot water.

However, if hot water is not kept under constant pressure, it will boil and become dangerous, so when immersing food in hot water, a preliminary chamber is set up in front of the pressure vessel containing the hot water, and the food is first brought into this chamber, then Close the lid of the pre-chamber and pressurize it so that the pressure in the pre-chamber is equal to that of the pressure vessel containing hot water, then open the connection between the pre-chamber and the pressure vessel and place the food in the hot water. Steps must be taken to introduce

When taking out sterilized food, the process must be reversed.

In practice, and depending on the amount of food to be processed, such operations have to be repeated many times.

As mentioned above, even if food is introduced directly into hot water,
Because this preliminary process is necessary, and usually involves rapid cooling of the hydrothermally treated food, equipment capable of carrying out these processes together becomes complex and bulky. .

Apart from well-mechanized mass production, it is difficult to realize a compact high-speed sterilizer suitable for relatively small-volume production that can directly immerse food products in hot water.

However, small hot water type high-speed sterilizers are advantageous for cooking and sterilizing wild vegetables, seafood, meat, etc. that have high added value and are suitable for relatively small-scale production, and are useful for cooking and sterilizing small- and medium-sized food products that are not suitable for mass production. Recently, there has been a strong demand for this in processing.

The present invention meets these demands.

According to the present invention, a lower can for heating articles containing pressurized hot water is provided to an upper can that serves as both a cooling chamber and a preliminary chamber, and both are vertically connected to each other, so that one pressure is maintained as a whole. Along with making it into a can,
The partition that seals the communication between the upper and lower cans is configured as a lifting platform that can be raised and lowered within the lower can, and the articles to be processed are loaded on this elevator, so that the inside of the lower can is always under pressure. In this way, the elevator is quickly lowered, and the articles are then immersed in hot water to be sterilized.

Although the structure of the present invention is as described in the claims, embodiments thereof will be described below.

What is shown in the attached drawings is an embodiment of the device according to the present invention, and according to this, the sterilizing device consists of a lower can 1 and an upper can 2, both of which are connected vertically, and are integrated into one whole. Constructed in a pressure can.

When the communication between the upper and lower cans is closed, each can becomes an independent pressure canister.

An elevating board 3 is provided which also serves for this purpose and is movable up and down within the lower can 1.

The lifting of the lift plate 3 is restricted by an inward locking flange 4 provided at the connecting position of both the upper and lower cans, where the direction flange 4 and the edge of the lift plate 3 are airtightly engaged.

In order to improve airtightness, a packing ring 5 is interposed between the lower surface of the inward flange 4 and the upper surface of the edge of the elevator plate 3.

Now, pressurized hot water is introduced into the lower can 1.

Hot water is supplied from a pipe 6 through a pump 7, and high-pressure steam is blown into the water in a pipe 8 through a pipe 9, and this is introduced into the lower can 1.

The hot water in the lower can 1 also flows through the external pipe 10, pump 7 and pipe 8.
At the same time, steam is blown in little by little through the tube 9 in order to maintain constant temperature conditions.

Compressed air is fed through the pipe 11 to keep the lower can 1 under pressure.

At the head of the upper can 2 is a lid 1 for charging articles to be processed.
2, and when the lid 12 is closed, both the upper and lower cans become one pressure canner.

Compressed air of the same pressure is introduced into the upper can 2 through the pipe 13 as in the case of the lower can 1.

The upper can 2 serves as a preliminary chamber for lowering articles into the pressurized hot water in the lower can 1, and at the same time serves as a cooling chamber for cooling the treated articles.

A cooling water supply pipe 14 and a discharge pipe 15 are connected to the upper can 2 for cooling, respectively.

As an elevating device for the lifting board 3, an air cylinder 16 is disposed outside the lower can 1, and its piston rod 17 is connected to the lower surface of the lifting board 3 through a bearing at the bottom of the lower can 1.

As compressed air is supplied to and discharged from the air cylinder 16 through the pipe 18, the elevator plate 3 moves up and down within the lower can 1.

In the above-described apparatus, first, the lifting platform 3 is raised and the lower can 1 is sealed, and then the steam valve 9a of the pipe 9 is opened, and the hot water supply valve 8a is also opened to fill the lower can 1 with approx. 1
Hot water at 35°C is introduced.

When a certain amount of hot water is introduced, the circulation valve 10a is opened and the hot water is circulated.

In order to maintain the inside of the lower can 1 under a predetermined pressure, the valve 11a is opened and compressed air at a constant pressure is introduced.

In this state, as shown in FIG.
The lid 12 of the lid 12 is opened, and food is loaded onto the lifting platform 3.

The food is sealed in aluminum or plastic bags (pouches), and the food is arranged and filled in a mesh case 19 on the lifting platform 3.

Then, close the lid 12 of the upper can 2, and close the valve 13a of the pipe 13.
Open it and introduce compressed air to pressurize it.

When pressurization is complete, the pressures in both the upper and lower cans are equal.

Next, as shown in FIG. 2, the piston rod 17 of the air cylinder 16 is lowered, and the elevator plate 3 is lowered.

In this way, the bagged food is immersed in pressurized hot water in just a few seconds.

When the food is immersed, the hot water temporarily loses heat to the food and its temperature drops, but at this time, the steam valve 9a is opened wider to introduce steam into the circulating hot water, and the temperature of the hot water is recovered. It will be done.

After the heat sterilization is completed, the food is lifted into the upper can 2 by the air cylinder 16 which raises the elevator plate 3, as shown in FIG.

At this time, the lower can 1 is disconnected from the upper can 2 by the elevator 3 and sealed.

When both cans are thus separated, the water supply valve 14a is opened and cooling water is introduced into the upper can 2 through the pipe 14.

The water used here is simultaneously discharged through pipe 15.

Heated food is thereby rapidly cooled down.

When the center temperature of the food falls sufficiently below 100° C., the injection of cooling water is stopped, and then the air pressure in the upper can 2 is released.

After all the water in the upper can 2 has been drained, the lid 12 is opened,
Case 19 containing bagged food is taken out.

A case containing the next packaged food to be sterilized is placed in the upper can 2 and placed on the lifting platform 3.

In this way, the next operation is started.

According to the present invention, since the food is directly immersed in hot water, contact between the food and the hot water can be achieved in a much shorter time than when hot water is injected.

Therefore, the time for the center temperature of the food to reach the predetermined sterilization temperature (cam amp time) becomes faster, and the sterilization effect can be enhanced.

In addition, it has a structure in which a lower can for heating and an upper can for cooling are vertically connected, and the upper can is configured as a preliminary chamber for pressurization, and the partition between the upper can and the lower can is The entire structure is simple, as it functions as an immersive elevator.

Note that, as is already clear from the above-described operating method, the sterilization method and device according to the present invention can be automated by sequence control to provide a more efficient food sterilization device.

[Brief explanation of the drawing]

1, 2 and 3 show longitudinal cross-sectional views of the apparatus according to the invention, each illustrating each stage of operation of the apparatus. 1... Lower can, 2... Upper can, 3...
... Elevating board, 4 ... Inward flange for locking, 5
... Packing ring, 7 ... Hot water circulation pump, 9a ... Steam valve, 10a ...
・Circulation valve, 11a... Pressurized air valve, 1
2... Lid, 13a... Pressurized air valve, 14... Cooling water supply pipe, 15... Cooling water discharge pipe, 16...・Air cylinder, 17・
...Piston rod, 18...Air pipe,
19... Net case.

Claims (1)

[Scope of Claims] 1. A lower can for heating articles containing pressurized hot water and an upper can for cooling articles into which cooling water is selectively introduced are vertically connected, and the entire pressure is maintained at one level. In addition to the can, an elevating board is provided in the lower can, and when this elevating board rises to a position where both cans are connected, the communication between the two cans is sealed there, and the lower can can be made into an independent pressure can, In this state, open the upper can, load the articles inside the upper can on the lifting board, then seal the upper can and pressurize it to the same pressure as the lower can, lower the elevator and load the goods into the lower can. The pressurized hot water food sterilization method involves immersing the can in pressurized hot water, and after a predetermined period of time, raising an elevator, sealing the lower can, and then introducing cooling water into the upper can. 2. A lower can for heating goods containing pressurized hot water and an upper can for cooling goods into which cooling water is selectively introduced are vertically connected to form one pressure can as a whole. A pressurized hot water food product in which an elevating plate is provided inside the can, and when the elevating plate is raised to a position where both cans are connected, the edge of the elevating plate airtightly engages with an inward locking flange. Sterilizer.