JPS59132852A - Washing and disinfection of living oysters - Google Patents

Abstract

PURPOSE:The sea water in the tank in which living oysters-containing cages are hung is filtered in the second and third tanks and sterilized by irradiation with ultraviolet lamps, then circulated to effect the disinfection of living oysters without the use of a disinfectant. CONSTITUTION:The living oysters are contained in cages 4 hung in the first tank 1 filled with sea water. During the circulation of the sea water, microorganisms and dirts such as filth are removed from the oysters and settle down to the bottom the tank. These microorganisms and dirts are carried together with the sea water through the pipe P1 to the second tank 2 and filtered off with the mesh cage filter 5, then sent through the pump 7 to the bottom of the third tank 3 where the remaining dirts and microorganisms are adsorbed on the crushed stones 6, finally the resultant clear sea water is irradiated with ultraviolet lamps 9 to effect disinfection and circulated to the first tank 1. Thus, living oysters are disinfected to a level below the microorganism number regulated by the food sanitation law with no use of a disinfectant.

Description

Detailed Description of the Invention The present invention is a novel method for washing and sterilizing raw oysters, which maintains freshness for a long time by washing and sterilizing raw oysters as ecologically as possible without using disinfectants. This is related to the method.

According to the Food Sanitation Act, the bacterial count for raw edible oysters must be less than 50,000E per gram of sample.

The optimum number of CoLi (E. coli) is 20 per 100g of specimen.
It is defined as 0 or less, and if it is higher than this, it is defined that it cannot be eaten raw.

However, the method of manufacturing raw oysters commonly used today, as shown in FIG. After washing the raw oysters, insert the raw oyster container 4' into the tank 9 filled with tap water W containing sodium hypochlorite (also known as chlorine) as shown in the same figure. At present, they are washed with shaking water, taken out, washed with ordinary tap water, and then vacuum packaged.

However, with this method, the surface of the raw oysters can be washed and sterilized, but the disinfectant causes the oysters to die prematurely or become dead or dead, and as a result, the stored filth and fungi cannot be effectively expelled, which accelerates the deterioration of freshness and shortens the shelf life of the oysters. In short, this is the main cause of food poisoning.

As a result of necessary research to eliminate the various disadvantages of the above-mentioned conventional methods, the present inventor has processed raw oysters for raw consumption as effectively as possible without using disinfectants, so that they can be kept for a long time with less fungi and good freshness. We proposed the following method for sterilizing and cleaning raw oysters.

The second tank is connected by a pipe P2 interposed between the bottom and the inside of the second tank, and a pipe P3 extending from the upper part of the crushed stone of the third tank is connected to the top of the first tank through an ultraviolet ray tube 9. The seawater in each tank was introduced into the mouth, and about 3
After the period of circulation, the storage basket 4 is taken out from the first tank 1 and the raw oysters X in the box are filled with actively purified fresh water'.
The process is completed by thoroughly washing the waste with water and vacuum packaging it, and the figure shows the filtered waste 2.
m indicates fungi.

As described above, the raw oysters X in the storage basket 4 in the first tank are constantly circulated (e.g., they respire ecologically in the purified seawater S), so that bacteria and filth on the surface of the oysters are gradually removed. At the same time as exfoliation, the built-in fungi are also discharged and fall to the bottom of the first tank 1 through the rough edges of the storage basket 4, whereupon they flow into the upper part of the second tank 2 through the pipe P0 facing the bottom, and then into the second tank 2. In the second tank, the seawater S that is roughly captured by the fine filter basket 5 inside the second tank and has passed through the filter end is pumped into the bottom of the third tank 3 via the pipe P2 by the pump 7, and the seawater S is collected inside the third tank 3. The microscopic dirt and bacteria in the seawater are all absorbed by the porous crushed stones 6# accumulated in the upper part of the tank, and the seawater becomes almost purified and is passed through the pipe P3 from the upper layer of the tank. The raw oysters X in the storage basket 4 are sterilized by the ultraviolet rays 9 installed in the pipe, and then returned to the first tank 1, so that the raw oysters X in the storage basket 4 are sterilized while retaining their ecology.

In this way, the adult oysters are finally activated and purified t) Fresh water W
Raw oysters with good freshness for raw consumption were obtained by washing the oysters in a vacuum cleaner and vacuum packaging them.

The raw oysters obtained by this method were analyzed and tested at the Japan Food Center, and the results are shown in the table below.

Analysis test results In the leftmost compartment in the table above, IH is 1 hour, 2H is 2 hours,
3H indicates treatment for 3 hours.

As described above, the present invention has an excellent effect in that the number of bacteria is far below the number of bacteria stipulated in the Food Sanitation Act, and is an extremely useful invention in terms of pollution prevention.

[Brief explanation of the drawing]

The figures show an example, in which FIG. 1 is a theoretical schematic diagram of an apparatus for carrying out the present method, and FIGS. 2(A) and 2(B) are schematic diagrams of a conventional processing method. 1 is the first tank, 2 is the second tank, 3 is the third tank, 4
is the storage end, 5 is the filter basket, 6 is the crushed stone, 7 is the pump, 8 is the shelf port 4.9 is the ultraviolet ray solution, D is the filth, bacteria, Pl, P2. P
3 is pipe, S is seawater, W is fresh water, and X is raw oyster.

Claims (1)

[Claims] A pipe connects the bottom of the first tank, in which a live oyster storage box is suspended in the seawater, and the upper part of the filter cage of the second tank, in which a filtration box is suspended in the seawater. Second
A pipe with a pump interposed between the bottom of the tank and the bottom of a third tank containing seawater in which crushed porous rocks were accumulated on a shelf network stretched over the middle part of the inside of the tank. The discharged pipe is introduced into the upper opening of the first tank f with or without ultraviolet rays, and the pump is operated to circulate the seawater in each tank for several hours. A method for washing and sterilizing raw oysters, which method comprises removing raw oysters from a storage basket.