JPS60116359A - Flash light emitting pasturizing method - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for sterilizing the inner surface of a container by flash light emission.

Conventionally, irradiation with a germicidal lamp has been used as one of the simple methods for sterilizing Class M bacteria.

Conventional germicidal lamps usually have a power consumption of about several tens of watts, and special types have a power consumption of about 200 watts. Tanushi,
When the power is about 200 watts, the length of the germicidal lamp becomes about 2 meters long, and the amount of germicidal radiation per unit arc length does not particularly increase significantly.

By the way, there are many types of fungi, and for example, in the case of fungi that absorb light well, such as black mold, only the black mold on the surface is sterilized, and the superimposed black mold located below the surface black mold is extremely sterilized. difficult to sterilize. Therefore, with conventional germicidal lamps, the sterilization time is long and the sterilization rate is low for bacteria that absorb light well, such as black mold.
There are drawbacks that make it not a very good sterilization method.

In general, the UV sterilization effect of germicidal lamps is determined by the following formula: % No. Number of bacteria before UV irradiation N: Number of bacteria after UV irradiation Q: Constant specific to bacteria L: Intensity of UV rays in the wavelength range effective for sterilization to: intensity of the ultraviolet rays irradiated to the surface layer of the bacteria t: irradiation time α: the ultraviolet absorption coefficient of the bacteria β: constant L: depth from the surface of the bacterial layer. Therefore, from these equations, it can be seen that in order to perform sterilization completely effectively, the value of 2-1 should be increased. Since α and β are constants specific to the bacteria, the final decision is whether to increase t or t. With conventional germicidal lamps, t was small, so t had to be increased, but even so, in the case of black mold, etc., only the surface layer could be sterilized, and the sterilization rate was low.

By the way, the original purpose of conventional sterilizing lamps is mainly to sterilize sheet-like objects, so most of them are fluorescent lamps in the form of straight tubes. In the case of a container with a similar structure, the irradiation amount differs near the opening and at the bottom, making it impossible to perform sterilization uniformly. In particular, when the container has a reverse tapered shape with a larger bottom area, there is a drawback that the sides cannot be treated sufficiently. For this reason, if the germicidal lamp is made into a U-shape and inserted into the container, the above-mentioned problem should be solved, but as mentioned above, the conventional germicidal lamp has a low germicidal dose due to arc penetration. Therefore, when attempting to use a large TFF, the sterilizing lamp becomes large, making it impossible to insert the lamp into a small container, and requiring a long irradiation time even in the case of a large container.

Furthermore, when sterilizing the inner surface of food containers, it is necessary to obtain a high sterilization rate in a short period of time, and in the unlikely event that a lamp or the like breaks during sterilization, its fragments may fall inside the container. Layering on the surface is not permitted.

Therefore, an object of the present invention is to provide a sterilization method that can treat the inner surfaces of food containers safely and in large quantities with a high sterilization rate. At this stage, a flash discharge lamp containing a rare gas as a luminescent component is inserted into the container through an ultraviolet-transmitting protection tube, and the flash discharge lamp emits light to sterilize the inner surface of the container.

Embodiments of the present invention will be specifically described below based on the drawings.

The box 1 may have a built-in power supply device for flash discharge such as a trigger coil as shown, and a cylindrical body 1a projects from the center of the lower surface and an opening 1b is formed.

This opening 1b has a flash discharge lamp holder 2 in its diametrical direction.
is installed, and the opening 1b is divided into two by this holder 2.

This holder 2 has an inner diameter of 8 mm and an arc length of 2 mm.
A U-shaped bulb flash discharge lamp 6 made of quartz glass is supported downward. Flash discharge lamps themselves are already widely used in industry, but they contain a rare gas, such as xenon gas, as a light emitting component.
Instantaneous light output is 104 to 10 times higher than conventional germicidal lamps.
'It is twice as strong. Furthermore, the cylindrical body 1a
An opening of a glass cup 4 made of quartz glass, which is an ultraviolet-ray transmitting protective tube, is fitted into the opening, and a flash discharge lamp 3 emits light inside the cup. Since this glass cup 4 is made of quartz glass,
The dose of ultraviolet light does not decrease as it passes through.

A ventilation duct 7 and a ventilation duct 8 connected to a fan 6 are provided on both sides of the box 10, and a wind barrel 9 is further connected to the ventilation duct 7, so that the cooling air blown is divided into two parts. It is forcibly introduced into one of the openings 1b to cool the flash discharge lamp 6.

Next, the food container 5, which is the object to be processed, is made of polystyrene plastic and has an opening of 10 crn x 14 cm.
It is box-shaped with a depth of about 12 crn, and is carried in the 11th stage by a conveyor (not shown) and stopped under the above-mentioned sterilizer, which is a sterilization station.

Then, the sterilizer is lowered or the container 5 is raised, the flash discharge lamp 3 is inserted into the container 5, and the flash discharge lamp 3 is flashed a predetermined number of times to sterilize the fungi attached to the inner surface of the container 5. When the sterilization process is completed, the container 5 and the flash discharge lamp 6 are separated, the treated container 5 is carried out (the untreated container 5 is carried in, and this cycle is repeated).

Foods such as yokels and puddings are then filled and packaged in this container 5 in a subsequent process, but the lid of this container 5 is separately sterilized. However, there are cases where the container 5 is a bag and the end of the bag is heated and crimped without using a lid. In addition to plastics, the material of the container 5 may also be metal, paper, or a material coated with plastic. Furthermore, although the glass cup 4 was fixed to the box in the sterilizer described above, it is also possible to have a structure in which the flash discharge lamp 5 and the glass cup 4 are separated and movable independently. It is sufficient if an ultraviolet-transmitting protection tube is interposed between the flash discharge lamp 6 and the flash discharge lamp 6.

Here, an example of flash sterilization is shown. When a capacitor with a capacitance of 600 .mu.F and a voltage of 2250 V is flashed inside a container 5 having the above dimensions, the irradiation intensity on the inner surface is about 2.degree. A predetermined amount of black mold is sprayed and adhered to the inner surface of the container 5 evenly over the entire area in advance, and a light emitting cycle is executed once per second at the above-mentioned irradiation intensity on this inner surface, and a predetermined number of times is applied to the inner surface of the container 5. After emitting light, 1
The entire inner surface was washed with 0117 sterile water using gauze, etc., and the number of remaining bacteria was determined. This inspection method is known as the inner surface wiping inspection method.
As a result, we were able to obtain a very high sterilization rate of 99.999% with one light emission and 99.99999% with 6 light emissions. By the way, if you sterilize by using a recently developed low-pressure mercury lamp with an inner diameter of approximately 1.5 times and an arc length of 960 +W and emit light at 5A and 110cm AC power, it will irradiate for 60 seconds. However, only 99 black molds could be sterilized, which shows how superior the sterilization method of the present invention is. Furthermore, since this low-pressure mercury lamp is large, it has a major disadvantage in that it cannot be inserted into a normal-sized food container. The half-width of the flash light emission (the time width of the height of the peak value) is 1000 μSec.
600 to 900 μSec, which is lower than this.
It is preferable to set it as approximately.

As explained above, the present invention utilizes a small flash discharge lamp with a large luminous output, so it can be inserted into a small food container, and it emits flash light while inserted. The inner surfaces of the containers can be efficiently sterilized in a short time, and together with the fact that they are moved one by one and sterilized when they reach the sterilization station 7, a large amount of food containers can be processed quickly. Next, a flash of light is emitted through an ultraviolet transmission protection tube, which acts as a protective wall.
Even if the flash discharge lamp or the like is damaged, its fragments will not adhere to the inner surface of the food container, making it safe. In addition, this protective tube allows the flash discharge lamp to operate in a closed space, so
If cooling is required, the flash discharge lamp can be effectively cooled by blowing cooling air into this closed space, and as a result, the flash discharge lamp operates efficiently and no flash errors occur. Since this cooling air does not come into direct contact with the container, there is no need to make this cooling air sterile.

Furthermore, since the ultraviolet-transmitting protective tube is present, the container does not come into direct contact with the heated flash discharge lamp, which has the advantage of preventing the container from being deformed or damaged by the heat. Therefore, according to the present invention, it is possible to provide a method for sterilizing food containers that can safely and in large quantities treat the inner surfaces of food containers with a high sterilization rate.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of an apparatus used in an embodiment of the present invention, and FIG. 2 is a side sectional view thereof. 1...Box 6...Flash discharge lamp 4...Glass cup (UV transmission image - tube) 5...Container Applicant: Meiji Dairies Co., Ltd. Ushio Inc. Agent Patent attorney Toranosuke Tahara

Claims (1)

[Claims] When the food containers are sequentially moved and reach the sterilization station, a flash discharge lamp containing a rare gas as a luminescent component is inserted into the container through an ultraviolet-transmitting storage tube, and the flash discharge lamp is caused to emit flash light. A flash sterilization method characterized by sterilizing the inner surface of a container.