JPH03183432A - Sterilization of dried fish granule - Google Patents

Abstract

PURPOSE:To accomplish the title sterilization surely, in large quantities using a simple equipment without impairing flavor, etc., in such a way that dried fish granules are made in layers on a hot carrying plate and continuously carried under far-infrared irradiation from above. CONSTITUTION:Dried fish granules are made in layers pref. 2-10mm thick on a carrying plate heated to pref. 50-250 deg.C, and continuously carried under far- infrared irradiation from above, thus making the objective sterilization. It is preferable that the residence time on the plate be 10sec to 3min and the far- infrared irradiation made so as to be 70-200 deg.C in the temperature of the granules as the end of the plate.

Description

[Detailed description of the invention] (Industrial application field) Fish flakes grains are generally co-produced in fish flakes manufacturing and processing industries.

It is sometimes eaten in granular form as it is, with extract added to make soup stock, or mixed with other foods. It is manufactured by crushing and classifying small pieces that are by-products of the fish flakes manufacturing process. Its particle size ranges from fine powder to 7-8
There are some sizes up to about mm.

Since there are many handling steps and the surface area itself is large, there is a high possibility that various bacteria will adhere to the surface, and sterilization treatment is required in the final process.

(Prior Art) In general, heating means is most often used to sterilize foods. When sterilizing fish flakes or their grains, steam heating, hot air heating, or a combination thereof is often used. As conditions necessary for sterilization, both temperature and time are strongly related, and the necessary degree of these factors depends on the type and number of bacteria. On the other hand, if the object is kept at high temperature for a long period of time, the quality as a food, that is, the flavor will be impaired.

Generally, in order to sufficiently sterilize food without sacrificing flavor, it is best to raise the temperature to a high temperature as quickly as possible, and then lower the temperature as soon as sterilization is complete.

A method using far infrared rays has also been considered and has been put into practical use for fish flakes, but it has not been put into practical use for fish flakes due to the complexity described below.

(Problems to be Solved by the Invention) When sterilizing fish flakes using steam or hot air, it takes a certain amount of time to raise the temperature of the mat to the level required for sterilization. Since the grains have a large surface area, when steam is used, the moisture content of the object increases, and when hot air is used, the moisture content of the object decreases, resulting in a serious loss of quality.

As mentioned above, far infrared rays are used for fish flakes, and in this case, even after several minutes to 20 minutes, the water content decreases by 1.
It is about 2%. However, in the case of grains, since they have a large surface area, they tend to lose moisture, so it is necessary to heat them up in a short period of time. Moreover, it is necessary to uniformly irradiate the entire surface with far-infrared rays within this time, and the purpose of the present invention, which requires advanced handling techniques, is to produce fish pieces that do not impair flavor and suppress water content as much as possible. The purpose of this invention is to provide a method for sterilizing grains.

(Means for Solving the Problems) In order to solve the above problems, the inventors of the present invention, as a result of extensive research, have invented a method of uniformly heating fish flakes to a high temperature within an extremely short period of time. By the way.

It was discovered that sterilization can be carried out sufficiently and the flavor of fish flakes can be maintained or improved.

That is, the present invention is a method in which fish flakes are spread thinly on a transport plate, the transport plate itself is heated, and the fish flakes are continuously transported while irradiating far infrared rays from above.

The main means for sterilization is far-infrared rays, but in order to make the sterilizing effect of far-infrared rays more powerful, it is necessary to raise the temperature of the fish flakes. As an auxiliary means for this purpose,
The temperature of the transport plate on which the fish flakes are placed is raised in advance. This temperature is suitably 50 to 250°C, preferably 100 to 200°C. In addition, in order to process the fish flakes evenly, it is necessary to spread them thinly and evenly on the processing surface, and this thickness is 10+
m or less, preferably about 2 to 7 mm. By strongly irradiating far infrared rays under the above conditions, the fish grains are heated to 70-200°C within 10 seconds to 3 minutes, preferably 100-150°C within 20 seconds to 1 minute. Increase temperature. With this method, sufficient sterilization can be achieved within an extremely short period of time, and the flavor of the object will not be impaired.

In the present invention, the transport plate may be a vibrating conveyor as shown in the embodiment, a type in which plate-like bodies are tilted, combined in multiple stages, and vibration is applied as necessary to make it easier to fall, or a belt conveyor, etc. However, in this case, it is preferable to construct the belt conveyor in multiple stages with different stages so that the grains can be turned over. With these methods, the fish particles are transported continuously, so they can be processed extremely efficiently.

(Effect) Temperature and time are important factors in killing bacteria attached to food, but generally the effect is greater if the temperature is raised even for a short period of time.

On the other hand, the quality of food itself changes as time passes at high temperatures, but for a very short period of time, quality changes can be avoided even if the food is at a fairly high temperature. Based on this principle, the two objects of the present invention were achieved by sterilizing fish flakes by the means described in the previous section.

Next, the present invention will be specifically explained with reference to the drawings.

FIG. 1 is an example of an apparatus for continuously sterilizing fish flakes using the means of the present invention.

In the figure, 1 is a raw material supply chute, 2 is a vibrating conveyor, 3 is a heater and its insulation material, 4 is a collection hopper, 5 is a far-infrared heater and its reflector, 6 is fish flakes, and 7
is the enclosure of the entire heated county.

The vibrating conveyor 2 vibrates in the horizontal direction, but by changing the forward and backward speeds (in the figure, slowing down from left to right and speeding up the opposite), the conveyed objects move forward. Although it is necessary to change the transport speed depending on the type and size of the particles, this can be done quantitatively by changing the vibration frequency. In order to process all the fish particles uniformly, it is desirable to turn the layer upside down, and for this purpose, steps were provided at several locations on the transportation surface.

3 is a heater and heat insulating material attached to the back side of 2 to heat 2.

There are various heating control methods that can be considered, but by attaching temperature needles and controllers to several locations on the transportation surface and on the surface of the far-infrared heater, and adjusting these temperatures with the output of the transportation vehicle heating heater and the far-infrared heater. , capable of reliable heat sterilization with stable quality.

[Example] Using the above equipment, a far infrared heater (15 mmφ rod shape, 150 mm interval) was set at 420°C, and the temperature of the transport plate was set at 20°C.
In a state heated to 0℃, dried bonito flakes (particle size on average 3 to 4 m)
m) was supplied for continuous sterilization.

The raw material is made by cultivating approximately 105 E. coli bacteria/g.

The frequency of the vibrating conveyor was adjusted so that the layer thickness was 5 mm and the transport time was approximately 50 seconds. At this time, the temperature of the fish particles at the exit of the conveyor was 130 to 140°C. In this state, a sample was taken during steady-state ffi transition, and bacteria measurements and sensitivity tests were performed.

The number of E. coli bacteria was 300 or less/g, and the sensitivity test was good.

(Effects of the Invention) According to the method of the present invention, fish flakes can be sterilized reliably and in large quantities using extremely simple equipment without impairing flavor or the like.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of an apparatus used for carrying out the present invention. 1... Fish flakes supply chute 2... Vibration conveyor 3... Heater and its heat insulating material 4... Recovery hopper 5... Far infrared heater 6... Fish flakes

Claims (2)

[Claims] (1) A method for sterilizing fish flakes, which comprises layering the fish flakes on a heated transport plate and transporting them continuously while irradiating far infrared rays from the top surface. (2) The temperature of the transport plate surface is maintained at 50 to 250°C, the layer thickness of the fish flakes is 2 to 10 mm, and the residence time on the transport plate is 1.
2. The sterilization method according to claim 1, wherein the far infrared rays are irradiated for 0 seconds to 3 minutes and at a temperature of 70 to 200° C. at the end of the transport plate.