JPH02203739A - Cleaning and sterilizing apparatus for food - Google Patents

Abstract

PURPOSE:To effect the sure separation and removal of bacteria from foods, especially perishable foods in a short time in high efficiency by washing the food with aseptic water under stirring while ozonizing and circulating the washing water. CONSTITUTION:Foods such as vegetables are washed in a top-opened washing tank 1 with water stirred by a stirring blade 2 and a stirring nozzle 2'. The washing water 1a is circulated with a pump 4 through an ejector 6, a gas-liquid mixer 7, an accumulation tank 8 and a gas-liquid separation tank 10 to the washing tank 1. In the course of the above circulation, the bacteria in the water are sterilized with ozone generated by an ozonizer 5. The ozone separated by the gas-liquid separation tank 10 is passed through a combustion heater 11 and a decomposition catalyst 12, converted to an ozone-free gas and discharged to the atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus suitably used for washing and sterilizing foods, particularly vegetables and fruits.

[Conventional technology] Conventionally, methods for sterilizing foods such as fruits and vegetables include: ■ Method using sodium hypochlorite ■ Method of irradiating with ultraviolet rays ■ Method of directly aerating ozone into the cleaning water in the cleaning tank. Are known.

[Problem to be solved by the invention]

However, in the method using sodium hypochlorite of the prior art (1) above, it is difficult to maintain a chlorine concentration effective for sterilization. That is, the sterilization rate decreases due to the reaction between organic matter and sodium hypochlorite, so a large amount of sodium hypochlorite is required to maintain the sterilization power. Also, when using sodium hypochlorite,
It causes a characteristic odor to fruits and vegetables, which is undesirable as a food product, and requires a large amount of water and time to remove this odor.

In the method of irradiating ultraviolet rays in (2), if the washing water is cloudy, the sterilizing effect will be reduced, and the energy of the ultraviolet rays will easily deteriorate the irradiated objects, impairing their freshness and damaging vegetables. is not desirable. Furthermore, since the lifespan of ultraviolet lamps is not very long, there is a problem that they are uneconomical.

The method (2) of directly diffusing ozone into the cleaning water in the cleaning tank has the following problems.

In other words, for example, if the gas phase ozone concentration is 20 mg/l (9340 ppm) at a water temperature of 25°C, according to Henry's law, the dissolved ozone concentration is 5.12
■/1 (5.12 ppm). In addition, the dissolved ozone concentration changes depending on the water quality and PAL, and the concentration of dissolved ozone changes depending on the water quality and PAL.
In alkaline water with H exceeding 8, the value decreases significantly.

As described above, since ozone is extremely poorly soluble in water, the concentration of dissolved ozone is low even under optimal conditions such as the gas-liquid contact area and contact time in the disperser that blows ozonated air and the reaction tank.
Most of it is released into the atmosphere.

Therefore, since the conventional sterilizer employs a method of directly diffusing ozone into the cleaning tank, it has the disadvantage of releasing a large amount of ozone into the atmosphere.

By the way, the ACGIH (American Council of Industrial Hygienists) basic ozone concentration is 0 in TWA (time load limit average value).
．． 1 ppm, so it is difficult to ensure safety with conventional devices in this respect as well.

Further, since the conventional sterilizer does not have a stirring mechanism in the tank, it is difficult to remove bacteria attached to the target object, and the sterilization effect cannot be said to be sufficient.

The present invention uses ozone to wash and remove adhering germs from foods, especially fresh foods, by stirring them with sterile water without impairing their properties, and sterilizes the washing water with ozone outside the tank. To provide a device that can clean and sterilize safely and efficiently in a short period of time by circulating the sterile water for continuous cleaning, separating the ozone used for sterilization and suppressing its release into the atmosphere. The purpose is to

[Means to solve the problem]

That is, the present invention includes a cleaning tank equipped with a stirring mechanism;
A means for sterilizing bacteria in the washing water by mixing and contacting the washing water led out from the washing tank with ozone generated by an ozone generator, and separating ozone contained from the sterilized washing water and circulating it again to the washing tank. The present invention is an apparatus for washing and sterilizing foods, which is equipped with a processing means for decomposing and discharging ozone separated from washing water, and solving the above-mentioned problems.

Examples of the mechanism for stirring water in the washing tank include stirring blades or nozzles, which effectively remove bacteria attached to fruits and vegetables and lead them out of the tank together with the washing water.

Ozone from an ozone generator is usually sucked into the unsterilized washing water through an ejector, and then the water is passed through a gas-liquid mixer using, for example, a static mixer, wire cloth, perforated plate, glass beads, etc. Reliable sterilization is achieved by sufficiently mixing the ozone and then bringing the cleaning water and ozone into sufficient contact in a device such as an accumulation tank (buffer tank). Ozone accumulation in the cleaning water at this time (injected ozone concentration A - wandering ozone concentration B after gas-liquid separation) x 100/
(calculated as the injected ozone concentration A) can be secured up to about 70%.

The wash water sterilized in this way is sent to the gas-liquid separation tank, and the ozone in the wash water separated here is removed via a discharge valve to an ozone decomposition device such as a heater installed at the top of the separation tank. It is decomposed by combustion and adsorption using a catalyst, etc., and released into the atmosphere as a safe non-ozone gas.

On the other hand, the sterile and sterile washing water from which the ossin has been separated returns to the washing tank again and is used for washing. Note that the ozone concentration on the water surface in the cleaning tank is approximately 0. Since it is less than lppm and safety is sufficiently ensured, an open cleaning tank can be used. The present invention will be further clarified by the following examples.

〔Example〕

FIG. 1 shows an embodiment of the device of the present invention, and its structure and operation will also be explained.

Reference numeral 1 denotes a washing tank with an open top, in which vegetables, etc., for example, are washed with washing water 1a. , 2 is a cleaning water stirring blade, and 2' is a stirring nozzle in which a part of the cleaning liquid drawn out from the cleaning water outlet pipe 3''a is blown into the cleaning tank 1 via the conduit 3d by the pump 14, and the cleaning water is Stirring is carried out.The stirring device may include only a stirring blade, but this is preferable because the stirring action is enhanced and the bacterial detachment effect is enhanced.

4 is the cleaning water 1 that passes through the sterilizer and the gas-liquid separation tank to the cleaning tank 1.
This is a line pump that circulates a. The cleaning water that has passed through the outlet pipe 3a, conduit pipes 3b and 3c by the pump 4 is sucked and mixed with ozone from the ozone generator 5 at the ejector 6. 7 is a gas-liquid mixer. For example, static mixer,
Alternatively, it is a tank filled with wire cloth, perforated plates, or glass beads, and when the cleaning liquid into which ozone is injected passes through, the ozone and the cleaning liquid come into sufficient contact, ensuring that bacteria in the cleaning water are sterilized. Furthermore, storage tank 8 (buffer tank)
More reliable sterilization is carried out during the period of residence there. 10 is a gas-liquid separation tank, where the sterilized cleaning liquid is then transferred and ozone is separated from the cleaning water. 0 The separated ozone passes from the top through a combustion heater 11 and a decomposition catalyst 12 and becomes a non-ozone gas and enters the atmosphere. is dissipated into.

On the other hand, the sterilized cleaning water from which ozone has been separated and removed in the gas-liquid separation tank 10 is returned to the cleaning tank 1 through the conduit 13 for cleaning, and such circulation is performed continuously.

In addition, in sterilization, it is preferable that the amount of ozone accumulated is in the range of 20 to 70%.

Next, a case in which cut cucumbers were washed using the device of the present invention and sterilized with sodium hypochlorite (comparative example)
The test results are as follows.

Comparison Team Sample: The cucumber (5mm cut) is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the present invention. 1... Washing tank, 2... Stirring blade, 2'... Washing water injection nozzle, 3a... Washing water outlet pipe, 4... Pump, [Effects of the invention]

Claims (1)

[Claims] 1. A cleaning tank equipped with a stirring mechanism, a means for sterilizing bacteria in the cleaning water by mixing and contacting the cleaning water drawn out from the cleaning tank with ozone generated by an ozone generator, and containing from the cleaning water after sterilization. 1. A food cleaning and sterilizing device comprising a processing means for separating ozone and circulating it again to the cleaning tank, and decomposing and discharging the ozone separated from the cleaning water.