CN1376034A - Antimicrobial agent made from seashells and method of using it to purify water and wash produce - Google Patents

Abstract

The present invention provides an antibacterial agent having a high antibacterial effect, which can be mass-produced at low cost using natural materials, and which does not cause any side effects when ingested into the human body. The antimicrobial agent can be prepared by calcining clam shell powder (Spisula sachalinensis) as raw material under inert gas until the final temperature reaches 700-2500 deg.C.

Description

Antimicrobial agent made from seashells and method of using it to purify water and wash produce

Background of the invention

1. Field of invention

The present invention relates to a kind of antibacterial agent, and this antibacterial agent is suitable for food processing and manufacturing industry, catering industry and family protection food from bacterial contamination, and is applicable to the disinfection, sterilization and pasteurization of medical industry and health welfare industry; The present invention It also relates to a method of desalination and purification of seawater and river water, and a method of washing or cleaning with the water purified by the antibacterial agent.

2. Introduction of existing technologies

Chlorine compounds are used as conventional antimicrobial agents. However, it sometimes produces chloroform during wastewater treatment and/or dioxins during incineration or incineration. With regard to antibacterial agents used as food additives in agriculture and fishery or seafood industry, there are, for example, synthetic antibacterial agents such as sulfamizin, carbodox, etc. used as animal medicines. However, considering food safety, its use must be strictly controlled, especially its residue must be lower than the standard value.

Therefore, especially in the field of food processing which may be ingested into the human body by mouth, there is a need for an antibacterial agent prepared with natural materials as components instead of the above-mentioned chemical antibacterial agents. For example, the research group of Professor Tadakatsu Shimamura, Faculty of Medicine, Showa University published a report on "Effect of Green Tea on O-157", which attracted the attention of many consumers. Although tea catechins are routinely used as food additives, they were not widely used until after this article was published.

Catechin, which has attracted attention as an antibacterial agent derived from natural materials, must be extracted from green tea as a raw material, so it is not suitable for mass production. Therefore, there is a need for a new antibacterial agent prepared from natural materials, which is harmless after being absorbed into the human body, can be mass-produced at low cost, and has a stronger antibacterial effect.

In particular, an antimicrobial agent derived from natural materials and harmless when absorbed by the body is considered to be important for water purification. Examples or situations at issue are listed below:

The first is seawater desalination. In Middle Eastern countries, fresh water is generally obtained from seawater by reverse osmosis membrane method, distillation method, refrigeration method (refrigeration method) or electrodialysis (electric dialysis). Bacteria thrive when substances such as salt are so removed from seawater. Therefore, chromium-based or chlorine-based antimicrobial agents are added to prevent bacterial reproduction. However, chromium-based or chlorine-based substances are extremely harmful to the human body, and the risk of carcinogenicity cannot be ruled out.

The second is the purification of river water. In the river water into which human living water (organic matter) is discharged, the BOD value is very high and produces a bad smell.

The third is the cleaning or washing of agricultural products. Post-harvest produce sometimes has pesticides attached to it. For this reason, in order to wash off the pesticides, the produce is washed with a synthetic detergent and then rinsed with ordinary water such as tap water or river water. However, because ordinary water has very little or no antimicrobial effect on its own, bacteria may multiply on the surface of agricultural products until these agricultural products reach ordinary consumers.

Summary of the invention

In order to solve the above problems, according to claim 1 of the present invention, an antibacterial agent prepared from shells is provided. The antimicrobial agent of the present invention can be obtained by heating shells under an inert gas and performing calcination at a temperature eventually reaching 700°C to 2,500°C.

Among the shells, clam (surf clam) is the best, because it is believed to have bactericidal power against general bacteria. But if calcined, it could be any of oyster, scallop, clam, turban shell and snail. Calcination creates many holes in the shell itself, so the contact area is increased, thus greatly improving the sterilization or disinfection ability.

Especially the clam shell powder obtained by calcining under inert gas shows strong and sustained antibacterial properties against bacteria or microorganisms such as Escherichia Coli O-157 even if only a little bit is added. Clam shell powder is also a natural material mainly containing calcium, so it is safe for the human body. Plus, it never contaminates air, water or soil when disposed of. It also has an effect that the seashells, which usually require a lot of disposal as waste, can be effectively utilized.

If the above-mentioned antibacterial agent is crushed until the maximum particle size is equal to or less than 100 μm, and the average particle size is 1 μm to 50 μm, it can be easily dissolved in water (especially warm water), thereby further improving its antibacterial effect.

Calcined shells manufactured from natural materials or natural components are described in No. 218 of the List of Existing Additives, in the revised editions of the Food Hygience Act and the Nutrition Improvement Act It is defined as burned calcium (mainly containing calcium compounds obtained by burning shells, etc.). Official bodies recognize it as safe for humans.

Therefore, with regard to the antibacterial agent of the present invention, it is best to use it for food industry, catering industry or family protection food from contamination by microorganisms or bacteria, and for disinfection, pasteurization in medical industry and medical welfare industry method and sterilization.

The antibacterial agent of the present invention suitable for seawater desalination can be used to contact fresh water obtained from seawater using any method in reverse osmosis membrane method, distillation method, freezing method or electrodialysis.

Because of the structure, the addition of chromium-based or chlorine-based disinfectants or bactericides to fresh water obtained from seawater can be eliminated or greatly reduced.

The above-mentioned antibacterial agent of the present invention suitable for purifying river water is filled in a net (including a shell permeable to river water), and the net is used to be placed in the river.

In addition to the antibacterial effect of the calcined shell itself, because it becomes a porous structure, bacteria that decompose organic matter can multiply on its surface, thereby promoting the purification of river water. Also, if the acidity of the river water increases, the calcined shells are dissolved into the river water to keep the pH in an optimum range.

The antibacterial agent of the present invention is suitable for cleaning agricultural products, and the agricultural products such as vegetables, fruits and the like after cleaning with synthetic detergent can be cleaned with water contacted with the antibacterial agent of the present invention.

Because this structure can inhibit the reproduction of microorganisms or bacteria on the surface of these agricultural products for a long time.

Brief description of the drawings

Fig. 1 is a schematic flow chart of a desalination method for obtaining fresh water from seawater;

Figure 2 (A) and (B) are an explanatory view of the river water purification method and a perspective view of the net used to be placed on the river bed, respectively;

3(A) and (B) illustrate the case of washing agricultural products and the case of rinsing after washing agricultural products.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, embodiments of the present invention will be explained in detail with reference to the accompanying drawings.

The clam used as the raw material of the antibacterial agent of the present invention is a kind of bivalves distributed in the sea area near the central part of the Japanese mainland and the northern part of the Sea of Japan. The clam is eaten canned, frozen or fresh; however, the shell is not used effectively. Therefore, its supply cost is low.

In order to produce the antimicrobial agent of the present invention from said clams, it is first necessary to crush the clam shells. After the clam shells are dried, they are coarsely ground by equipment such as a grinder, so that the maximum particle size is equal to or less than 5mm.

The ground clam shells are then added to an autoclave with a stirrer and calcined under an inert gas while stirring. The inert gas is preferably nitrogen. The method of increasing the temperature is not a problem; however, the final temperature needs to reach 700°C to 2,500°C, more preferably 900°C±50°C, and this temperature needs to be maintained for 3 minutes or longer.

If the final temperature is lower than 700°C, it is difficult to obtain antibacterial properties. If it exceeds 1000°C, the active part in the shell particles is destroyed, so it is also impossible to obtain antibacterial properties. In addition, if the calcination time is less than 3 minutes, it is also difficult to obtain antibacterial properties. The calcination time may be extended, but it is preferably 3 to 5 minutes from the viewpoint of cost.

Next, the calcined shell particles are cooled under an inert gas, and then further finely ground to separate powders with a maximum particle size equal to or less than 100 μm and an average particle size of 1 μm to 50 μm, more preferably 2 μm to 5 μm.

If the maximum particle size is larger than 100 μm or the average particle size is outside the range of 1 μm to 50 μm, they are insoluble in drinking water and precipitate out, making it impossible to exert their effect. If the average particle size is less than 1 μm, they absorb water vapor so that they become solid. This will be difficult to handle.

However, depending on the application, unground calcined shells can also be used. If they are ground into tiny particles, they are soluble in water. The effect is thus more pronounced; however, this effect disappears within a short time. In order to maintain the effect for a long time, it is preferable to use unground calcined shells, or to mix ground shell powder with a binder and then calcined, thereby forming a predetermined antibacterial agent.

The antibacterial agent produced by the above method is effective against Escherichia coli (Esherichia Coli) such as O-157 etc., food poisoning bacteria such as Staphylococcus aureus (Staphylococcus aureus), Pseudomonas aeruginosa (Pseudomonas aeruginosa), fungi (Eumycetes), Salmonella (salmonella) , enteritis vibrio (enteritis vibrio) and viruses are effective.

As for the specific application of the antibacterial agent of the present invention, it can be used as an additive to foods such as boiled fish sauce (called kamaboko in Japan), drinking water, water for hand washing, and dental materials such as artificial dentures. Alternatively, it can be canned for home use in antimicrobial powder packs, or used to sanitize drinking water in disaster and emergency situations. It can be added as an antimicrobial functional additive to cleaning wipe sheets, diapers, wallpaper or building materials. Regarding other usage methods of the antibacterial agent of the present invention, it itself can be made into ceramic products, or utilize its antibacterial effect to produce sterilizing devices or instruments.

The antibacterial agent of the present invention has stronger antibacterial ability than tea catechin or oyster shell. Therefore, it is characterized in that an antibacterial effect can be obtained even with a small amount, and this effect can last for a long time. For example, for drinking water or other substances to be disinfected, it is sufficient to add 0.025% by weight thereof. More amounts can be added according to usage. The antibacterial effect can be maintained for a long time, and it has been confirmed that the effect can be maintained for more than 48 hours. (embodiment) the production of antibacterial agent:

After the clam shells are dried, they are pre-ground to a size of 2mm-3mm. Wherein get 500g and add in the autoclave with stirrer, the volume of autoclave is 2 liters, wherein has been full of nitrogen. Run the mixer slowly while starting to heat up. This process was continued until the temperature reached 900°C. After calcining clam shells at 900° C. for 5 minutes, the heating was stopped. Then, the clam shells were cooled in a nitrogen stream until the temperature in the autoclave returned to room temperature.

After cooling, the calcined shell powder was removed from the autoclave and further crushed with a mortar. Particles equal to or smaller than 50 μm are selected by a classifier, thereby producing the antibacterial agent of the present invention.

The component concentrations of this antibacterial agent are shown in Table 1 below (analyzed according to the soil nutrient analysis method formulated by the Yamagata-ken Rikagaku-Bunseki (Physical and Chemical Analysis) Center: Yama-Bun-Se No. 778).

Table 1 Detection components Concentration (% wet weight) minimum detection value magnesium 0.04 Phosphor bronze 0.02 Potassium 0.07 calcium 25. manganese 0.01 iron 0.07 copper not detected 0.01 zinc not detected 0.01 molybdenum not detected 0.01

In addition, bamboo charcoal (charcoal of bamboo) crushed in the same manner as above and adjusted to be equal to or less than 50 μm particles is mixed with the above-mentioned antibacterial agent made from clams at a weight ratio of 1:1 to make another embodiment of antibacterial agent.

Oyster shells were further used instead of clams, which were calcined and crushed in the same manner as above, thereby making oyster shell powder. Test bacteria:

Three kinds of bacteria, namely Escherichia coli ATCC 8739, Staphylococcus aureus ATCC 6538 and Pseudomonas aeruginosa ATCC 9027, were used for 18 hours at 37°C on a medium such as a blood agar plate DD detection medium suitable for the growth of general bacteria. experiment method:

Each prepared antibacterial agent was dissolved in distilled water to a predetermined concentration. Then, each of the above-mentioned test bacteria was added to the distilled water in which the antibacterial agent was dissolved so as to reach a concentration of about 106 cells/ml.

After adding each test bacteria, stir well and let stand at room temperature. After reaching the predetermined time, samples were taken to measure the number of cultured bacteria (cells/ml). (Example 1)

Use the distilled aqueous solution (1% (weight), 0.5% (weight), 0.1% (weight) and 0.05% (weight)) of the antibacterial agent that is made by clam by the above-mentioned method, detect its to escherichia coli, Staphylococcus aureus and the bactericidal effect of Pseudomonas aeruginosa. The results are shown in Table 2. (Example 2)

By the same method of above-mentioned embodiment 1, exception is to use the mixed antibacterial agent made by clam and bamboo charcoal (weight ratio: 1: 1) to replace the antibacterial agent made by clam, detect the sterilizing action of this mixed antibacterial agent. The results are also shown in Table 2. (Example 3)

By the same method as above-mentioned Example 1, except that the antibacterial agent made from oyster shells was used instead of the antibacterial agent made from clams, the sterilizing effect of the antibacterial agent was tested. The results are also shown in Table 2.

Table 2 Examples and comparisons Concentration of antimicrobial agent (% by weight) Escherichia coli Staphylococcus aureus Pseudomonas aeruginosa 15 minutes later 24 hours later 15 minutes later 48 hours later 15 minutes later 24 hours later Example 1 1% 0.5% 0.1% 0.05% <20<20<20<20 <20<20<20<20 <2-1.9×10 ² - <2-60- <2-<2- <2-<2- Example 2 1% 0.5% 0.1% 0.05% ＜20＜20＜204.0×10 ³ <20<20<20<20 2.0×10 ² -2.0×10 ⁴ - 80-2.0×10 ² - <2-<2- <2-<2- Control 1 1% 0.5% 0.1% 0.05% <206.4×10 ² 2.5×10 ³ 2.5×10 ⁵ ＜20＜202.5×10 ⁶ 1.2×10 ⁵ 40-4.0×10 ⁵ - 2-5.2×10 ⁵ - <20-2.2×10 ² - 2-<1- Blank control: distilled water 6.0×10 ⁵ 4.0×10 ⁵ 4.0×10 ⁵ 3.6×10 ⁵ 8.0×10 ⁵ 4.0×10 ⁶

Obviously, the test results in Table 2 show that the antibacterial agent made from clams can still achieve sufficient sterilization effect at a low concentration of 0.05%. This effect was maintained not only after 24 hours, but also after 48 hours. As far as the oyster antibacterial agent is concerned, this effect can be achieved at a concentration of 1%. Therefore, it can be said that clam antimicrobials are the most effective. (Example 4)

The concentration of the antibacterial agent made by clams in the distilled water solution is reduced to lower than the concentration of embodiment 1 (i.e. 0.025% (weight) and 0.005% (weight)), and it is detected to the sterilization of Escherichia coli and Staphylococcus aureus effect. The results are shown in Table 3. (Example 5)

By the same method as in the above-mentioned Example 4, except that the antibacterial agent made from oysters was used instead of the antibacterial agent made from clams, the sterilizing effect of the antibacterial agent was tested. The results are also shown in Table 3.

table 3 Examples and comparisons Antibacterial agent concentration (% by weight) Escherichia coli (2.0×10 ⁵ ) Staphylococcus aureus (2.0×10 ⁵ ) 1 hour later 24 hours later 1 hour later 48 hours later Example 3 0.025% 0.005% 4 -1.6×10 ⁵ - <2 -4.0×10 ⁴ - 20 -2.4×10 ⁴ - <2 -2.0×10 ² - Comparative example 0.05% -0.01% - - - - - - - 4.0×10 ² -4.8×10 ⁴ - <2 -6.0×10 ² -

As is evident from the test results in Table 3, the antibacterial agent made of clams can achieve a sufficient sterilizing effect even at its lower concentration of 0.025%.

Next, a further sterilizing action test was carried out at the Yamagata-ken Rikagaku-Bunseki (Physical and Chemical Analysis) Center for the following antibacterial agent, which is clam antibacterial agent (clam calcium powder) of the present invention, calcium bicarbonate , scallop shells, clam shells, conch shells, snail shells or oyster shells. The results are shown in Tables 4 to 16 below.

Table 4

(sample: clam calcium powder (the present invention)) General bacteria count (/ml), standard agar medium method Escherichia coli colony count, deoxycholate medium method Test solution (mixed drainage hot spring containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 120. 0. Control solution (mixed drainage hot spring) 11,000. 410.

table 5

(Sample: Calcium bicarbonate (calcined at 1,000°C)) General bacteria count (/ml), standard agar medium method Escherichia coli colony count, deoxycholate medium method Test solution (river water containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 56. 0. Control solution (river water) 17.000. 57.

Table 6

(Sample: heavy calcium carbonate (uncalcined)) General bacteria count (/ml), standard agar medium method Escherichia coli colony count, deoxycholate medium method Test solution (river water containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 18.000. 26. Control solution (river water) 17.000. 57.

Table 7

(Sample: dried scallop) General bacteria count (/ml), standard agar medium method Escherichia coli colony count, deoxycholate medium method Test solution (river water containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 720. 0. Control solution (river water) 3,100. 56.

Table 8

(Sample: unbaked scallop) General bacteria count (/ml), standard agar medium method Escherichia coli colony count, deoxycholate medium method Test solution (river water containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 4,100. 62. Control solution (river water) 3,100. 56.

Table 9

(sample: dried clam) General bacteria count (/ml), standard agar medium method Colony count of Escherichia coli, deoxycholate medium method Test solution (river water containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 630. 0. Control solution (river water) 3,100. 56.

Table 10

(Sample: uncalcined clams) General bacteria count (/ml), standard agar medium method Colony count of Escherichia coli, deoxycholate medium method Test solution (river water containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 3,700. 48. Control solution (river water) 3,100. 56.

Table 11

(Sample: dried salamander shellfish) General bacteria count (/ml), standard agar medium method Colony count of Escherichia coli, deoxycholate medium method Test solution (river water containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 720. 0. Control solution (river water) 3,100. 56.

Table 12

(Sample: uncalcined salamander) General bacteria count (/ml), standard agar medium method Colony count of Escherichia coli, deoxycholate medium method Test solution (river water containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 3,700. 54. Control solution (river water) 3,100. 56.

Table 13

(Sample: dried snail shell) General bacteria count (/ml), standard agar medium method Colony count of Escherichia coli, deoxycholate medium method Test solution (river water containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 650. 0. Control solution (river water) 3,100. 56.

Table 14

(Sample: uncalcined snail shell) General bacteria count (/ml), standard agar medium method Colony count of Escherichia coli, deoxycholate medium method Test solution (river water containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 3,600. 47. Control solution (river water) 3,100. 56.

Table 15

(Sample: dried oyster shell) General bacteria count (/ml), standard agar medium method Colony count of Escherichia coli, deoxycholate medium method Test solution (river water containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 620. 0. Control solution (river water) 3,100. 56.

Table 16

(Sample: uncalcined oyster shell) General bacteria count (/ml), standard agar medium method Colony count of Escherichia coli, deoxycholate medium method Test solution (river water containing 0.1% (weight/volume) sample, sampled 10 minutes after adding sample) 3,700. 62. Control solution (river water) 3,100. 56.

From the above Table 4 to Table 16, it can be clearly seen that clam shell powder is inferior to calcium bicarbonate in sterilization ability or effect; but better than other shell powders. Also, including the other shells, all calcined and uncalcined samples had significant differences in sterilizing ability or efficacy.

Hereinafter, specific embodiments of obtaining fresh water from seawater, purifying river water, and cleaning agricultural products will be explained with reference to FIGS. 1 to 3 .

Figure 1 is a flow chart of obtaining fresh water from seawater. First, seawater is pumped into a reservoir using a pump.

Next, there is a separation tank at the lower part of the reservoir, where the reverse osmosis membrane divides the tank into a first chamber and a second chamber, and the seawater in the reservoir enters the first chamber of the pool through a pipe.

The water level pressure difference acts on the seawater in the first chamber, and the fresh water flows into the second chamber through the reverse osmosis membrane, from which NaCl and the like are removed.

The fresh water in the second chamber is sterilized by passing through a column filled with an antimicrobial agent made by roasting shells such as clams. Finally, the fresh water is supplied to the desired location or location.

Figure 2(A) shows a method of purifying river water, while Figure 2(B) shows a perspective view of a net provided or placed on a river bed. In this embodiment, the net is filled with calcined shells such as clams and the net can be placed in a river bed.

If this embodiment is considered from the viewpoint of maintaining the purification effect for a long time, it is preferable not to grind the calcined shell. Since the calcined shell becomes a porous shell with a large specific surface area, bacteria that decompose organic matter tend to multiply thereon. When the acidity of the river water becomes high, the shell contents dissolve into the river water, thereby maintaining the constant pH value of the river water.

Fig. 3(A) shows the condition of washing agricultural products, and Fig. 3(B) shows the condition of rinsing after washing. In this embodiment, a produce basket is submerged in a container containing a synthetic cleaning agent. Then, the basket is taken out therefrom, and the water contacted with the above-mentioned calcined shell is sprayed on the agricultural product through a sprayer, thereby removing the synthetic cleaning agent adhering to the surface of the agricultural product.

Just as the above comprehensive introduction, the antibacterial agent of the present invention is prepared by calcining the shell powder of clams etc. under inert gas, and it has strong sterilizing effect or ability.

More specifically, the antibacterial agent of the present invention has sterilizing effect on Escherichia coli such as O-157, food poisoning bacteria such as Staphylococcus aureus, Pseudomonas aeruginosa, fungi, Salmonella, Vibrio enteritidis, etc., and even viruses at low concentrations. effect, and its sterilizing effect can be maintained for a long time.

In addition, shell powder of clams etc. is a natural material mainly containing calcium, which is also used as a food additive, so it is possible to provide an antibacterial agent that is safe for the human body and does not pollute the air even when it must be processed , wastewater and soil.

And when using the antibacterial agent of the present invention, the shells of clams and the like can be effectively used for desalination of seawater, purification of river water or cleaning of agricultural products, etc., and it is a very troublesome thing to deal with them conventionally.

Claims (9)

CLAIMS 1. An antibacterial agent produced by heating shells under an inert gas and calcining the shells at a temperature eventually reaching 700°C to 2,500°C. 2. The antimicrobial agent as defined in claim 1, wherein the shell is a clam shell. 3. The antibacterial agent as defined in claim 1, wherein the shell is any one of oyster, scallop, clam, salamander and snail. 4. The antimicrobial agent as defined in claim 1, wherein the shells are crushed before or after calcination. 5. The antibacterial agent as defined in claim 4, wherein the crushed shells have a maximum particle size equal to or less than 100 μm and an average particle size of 1 μm to 50 μm. 6. the antibacterial agent defined in claim 1, this antibacterial agent comprises the powder obtained after bamboo charcoal is ground. 7. A method for desalinating seawater, the method comprising the following steps: obtaining fresh water from seawater by any of the methods of reverse osmosis membranes, distillation, freezing or electrodialysis; and Contacting said fresh water with an antimicrobial agent as defined in any one of claims 1 to 6. 8. A method for purifying river water, the method comprising the steps of: Filling a net with the antimicrobial agent defined in any one of claims 1 to 6; and The net was placed in the river. 9. A method of cleaning agricultural products, the method comprising the following steps: washing produce, including vegetables and fruit, with synthetic detergents; and The washed produce is then rinsed with water contacted with an antimicrobial agent as defined in any one of claims 1 to 6.

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