JPH0126669B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a retort sterilization method, and more particularly to a batch-type steam retort sterilization method for canned goods such as canned coffee.

(Prior art) When conventionally canned food is sterilized by steam heating in a batch-type retort, after the sterilization process at the sterilization temperature (for example, 120°C) is completed, fresh water such as tap water or ground water (usually 25°C) is poured into the retort. ℃ or below) until the water is almost full, and the temperature of the canned food is approximately 40℃.
After cooling the canned food to a temperature of 35 to 42 degrees Celsius (usually 35 to 42 degrees Celsius), the canned food is sent out from a retort.

During this cooling, the temperature of the cooling water increases, so the retort has a large capacity (for example, about 10 to 20 tons).
If there are a large number of canned goods to be stored, it is difficult to cool the canned goods to around 40℃ by supplying fresh water until the water is almost full at once. The temperature is almost at equilibrium. Therefore, after reaching this almost equilibrium state, fresh water is replenished into the retort while overflowing the cooling water to maintain the almost full water state, and the canned food is kept for about 40 minutes.
It was cooled down to ℃.

Canned food is cooled in the retort to approximately 40°C (35-42°C) because this temperature is the upper limit at which bacterial resurgence does not occur during room temperature storage. Furthermore, if canned goods are cooled to a lower temperature than this temperature range, not only will the processing time be unnecessarily prolonged, but also undesirable phenomena such as condensation forming on the surface of the canned goods may occur during high humidity in the summer. This is because it is easy.

(Problem to be solved by the invention) As described above, replenishing fresh water into the retort while overflowing for one sterilization treatment requires a large amount of fresh water, especially when the retort has a large capacity. If the new water is tap water, this will lead to an increase in water costs, and if the new water is groundwater, there is a risk of violating pumping regulations, and in both cases, there will be problems such as higher drainage fees. .

(Object of the Invention) The present invention has been made in view of the problems of the prior art described above, and an object of the present invention is to reduce the amount of fresh water used as cooling water, and to reduce the amount of fresh water used as cooling water. An object of the present invention is to provide a steam retort sterilization method suitable for type retorts.

(Structure of the Invention) In order to achieve the above object, the present invention supplies old water from the old water tank to the retort until it is almost full after the sterilization process is completed, so that the temperature of the canned food and the old water is almost in equilibrium. After first cooling the canned food until it reaches
Draining the old water from the retort, immediately supplying new water at 25°C or lower until the retort is almost full, and secondary cooling the canned food to approximately 40°C;
A steam retort sterilization method for canned goods, characterized in that the new water is then discharged from the retort, fed into the old water tank, and used as old water for primary cooling after the next sterilization step. This is what we provide.

(Example) The present invention will be described below with reference to the drawings.

In Figure 1, 1 indicates a large capacity (usually about 10 to 20
The retort 1 is a horizontal batch type retort with a capacity of 1.5 tons, and a large number of canned goods 4 loaded in a basket 3 are accommodated in the retort 1 via a partition plate 2, and cooling water 5 is supplied until it is almost full. 6 is a fresh water tank, and fresh water such as underground water or tap water is supplied from a water source 7. The temperature of the new water can be reduced to approximately 40°C (35-42°C) in a short period of time, on the order of a few minutes.
For subsequent cooling, it is desirable to be below 25°C. In this respect, it is preferable to use groundwater as the fresh water, which can stably maintain a water temperature of about 10 to 20°C throughout the year. Fresh water is supplied to the retort 1 from above via a pump 8 and a valve 9.

10 is an old water tank. In this specification, old water refers to fresh water that is sent to the old water tank 10 after being used for secondary cooling of the canned goods 4 in the retort 1. The temperature of the old water is usually below about 40°C. After the secondary cooling of the cans 4 is completed, the cooling water 5 (new water) is sent to the old water tank 10 via the pump 11 and the valve 12, and is temporarily stored as old water. For the primary cooling of the cans 4, old water is supplied into the retort 1 from above via the pump 13 and valve 14. The old water that has undergone primary cooling is led to a drainage tank 16 via a pump 11 and a valve 15, and is discharged to the outside via a valve 17. Note that 18 is a steam valve.

(Function) Figure 2 shows the internal volume of the system equipped with the above cooling system.
1 horizontal batch type retort of 20 m ³ , 4 canned coffee
This figure shows an example of a heating/cooling diagram when 5 baskets 3 containing about 5,000 baskets (each having a capacity of 250 grams) are stored and subjected to retort steam sterilization treatment. Note that the temperature indicates the temperature inside the can.

That is, after placing the basket 3 in the retort 1, sealing it and opening the steam valve 18, the canned food 4 is heated by the steam, reaching 120°C in about 13 minutes, and reaching 120°C.
Sterilize at 123°C for 20 minutes (times a-b).
Immediately close the steam valve 18 and open the valve 14,
For example, old water at about 37° C. is primarily supplied from the old water tank 10 into the retort 1 until it is almost full (time b-c). During this primary water supply and the primary cooling period (time c-d) after almost full water, the temperature of the canned food 4 decreases, while the temperature of the old water increases, in this case approximately
At 65°C, both reach an almost equilibrium state.

Immediately, the valve 15 is opened to send the heated old water to the drainage tank 16 (time de) to perform primary drainage.

Immediately after the primary drainage is completed, open the valve 9 and pour fresh water at, for example, 20°C into the retort 1 from the fresh water tank 6.
Water is supplied until the tank is almost full, and secondary water supply is performed (times e-f). During this secondary water supply and the secondary cooling period (time fg) after the water is almost full, the temperature of the canned food 4 drops to 38°C in the case shown in the figure, and the temperature of the new water also rises to about this temperature. The valve 12 is immediately opened and the heated and used new water is sent to the old water tank 10 as old water (time gh) to perform secondary drainage. The old water in the old water tank 10 is reused for primary cooling after the next sterilization. After the secondary drainage, the door (not shown) of the retort 1 is opened, and the sterilized and cooled canned goods 4 are sent out from the retort 1.

In the above example, the conventional overflow method
Although 16 tons of fresh water was required, in the method of the present invention, the amount of fresh water supplied was 12 tons. In other words, the amount of fresh water that is overflowed can be reduced. Furthermore, since the temperature difference between the new water and the old water is smaller than the sterilization temperature, the cooling time will not be prolonged due to the use of the old water.

(Effects of the Invention) According to the present invention, it is possible to reduce the amount of fresh water used for cooling the inside of the retort after the sterilization process is completed. The benefits of this savings are greater as the capacity of the retort increases.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of an apparatus used to carry out the method of the present invention, and FIG. 2 is a diagram showing the relationship between the internal temperature of a can and time when the method of the present invention is carried out. 1... Retort, 4... Canned food, 6... Fresh water tank, 1
0...Old water tank.

Claims (1)

[Claims] 1. After the sterilization process is completed, feed old water from the old water tank into the retort until it is almost full, and then store the canned goods for 1 hour until the temperature of the canned goods and the old water reach an almost equilibrium state.
After cooling, the old water is discharged from the retort,
Immediately feed new water at 25°C or below into the retort until it is almost full, cool the canned food secondary to approximately 40°C, then drain the new water from the retort and replace the old water with water. A steam retort sterilization method for canned goods, characterized in that the water is sent to a tank and used as old water for primary cooling after the next sterilization process.