JP2001231525A - Method for sterilization of food - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a food sterilization technique free from the deterioration of the quality such as degradation or denaturation in the sterilization of a food. SOLUTION: A food such as hen's egg is brought into contact with an aqueous solution containing hydroxyl radical to sterilize soil-originated spore-forming bacteria such as Bacillus cereus. The hydroxyl radical is produced by mixing and reacting ozone to an aqueous solution of hydrogen peroxide and/or peracetic acid. The mixing ratio of ozone to hydrogen peroxide and/or peracetic acid is 1:10 to 10:1. The contact of the food with the aqueous solution containing hydroxyl radical comprises one or plural kinds of physical treatments selected from brushing, showering and vibration energy application on the food immersed in the aqueous solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sterilizing food. More specifically, the present invention relates to a method for sterilizing food, which comprises contacting an aqueous solution containing a hydroxyl radical with food.

[0002]

2. Description of the Related Art Food poisoning prevention has been carried out for many years, but it is still inadequate, so that many food poisonings occur every year. Prevention of food poisoning can be achieved by a combination of many technologies such as food sterilization technology, storage and transport technology, but in modern dietary habits, the consumption of processed foods is increasing. is important. In recent years, among poisoning of food, attention has been paid to food poisoning derived from eggs, and studies on countermeasures have been promoted. as a result,
Various sterilization techniques for Salmonella have been developed, and the number of commercially available eggs that are contaminated with Salmonella is decreasing. On the other hand, since many spores such as Bacillus cereus are derived from soil, many eggs of Bacillus cereus contaminated are still in circulation, and countermeasures are required. The most general sterilization method is sterilization by heating. However, foods are generally denatured or degraded by heating, and sterilization by heating often reduces the commercial value of foods. Since spores have high heat resistance, the use of the heat sterilization method significantly deteriorates the quality of food, and is often not applicable.

[0003] In particular, foods having heat coagulability, such as chicken eggs, are difficult to sterilize by heat. Therefore, as an alternative method, a method in which meat is treated with a hypochlorite solution in Japanese Patent Application Laid-Open No. H11-89509. Is disclosed. Attempts have been made to disinfect chicken eggs by dissolving acid, alkali, detergent, EDTA, disinfectant, etc. in water during washing, but they cannot be disinfected effectively, or the quality of edible parts of eggs deteriorates. There was a problem. Further, as a method of using other chemicals, for example, eggshells are treated with ozone gas in JP-A-10-27224, JP-A-10-119919, and JP-A-9-84482, and JP-A-3-285.
635, an ozone-adsorbing microorganism suppressing material using silica gel, JP-A-7-16033, JP-A-8-28977
Dioxide and chlorine dioxide decomposition products in Table 2
Molecular or peroxide oxygen or ozone / carbon monoxide in 501209, acid water obtained by electrolysis of water in JP-A-7-255369, JP-A-10-276
605, a technique such as a combination of a strong alkaline functional water and a strong acidic functional water.

However, bacteria develop enzymes such as catalase, glutathione, alkaline hydroperoxide reductase, and superoxide dismutase in response to oxygen stress during the course of evolution. When growth ceases, some produce special heat shock proteins or form spores to increase oxygen stress tolerance. Since these are resistant to hydrogen peroxide, hypochlorous acid, ozone, etc., which can be effectively sterilized when bacteria are actively growing, these techniques are not effective for specific bacteria. Some were not effective against spores.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for sterilizing food without deteriorating the quality of the food.

[0006]

In view of these circumstances, the present inventors have conducted intensive studies in order to solve the problems, and as a result, hydroxy radicals are strongly killed against bacteria that are resistant to oxygen stress. Have an effect,
The present invention has been reached. That is, the present invention is a method for sterilizing food, comprising contacting an aqueous solution containing a hydroxyl radical with the food. Hereinafter, the present invention will be described in detail.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the gist of the present invention is to provide a method for sterilizing food by bringing an aqueous solution containing a hydroxyl radical into contact with the food. The food in the present invention is not particularly limited, such as fresh foods such as vegetables, meat, eggs, seafood and fruits, cut vegetables, pickles, hams, sausages, prepared dishes, and processed foods such as dried foods and frozen foods. It is particularly effective for fresh foods such as vegetables, eggs and fruits that cannot be sterilized by heating. Above all,
Eggs are particularly effective because of their high risk of food poisoning. Also,
Bacillus bacteria such as Bacillus cereus, which is a kind of food poisoning bacteria, are spores that form spores and become resistant to heat and chemicals when the environment deteriorates. The technique of the invention is effective.

[0008] The aqueous solution containing a hydroxy radical in the present invention is water or an aqueous solution containing the above-mentioned hydroxy radical. The production method is not particularly limited, and any known method may be used. Here, the hydroxyl radical refers to a molecule HO · which is irradiated with water to water or is derived from hydrogen peroxide in the presence of an iron catalyst (Fenton reaction).
It is. Hydroxy radicals are extremely reactive and have a very short life because the rate at which two molecules of hydroxy radicals combine to form hydrogen peroxide is as fast as 5,000,000 / Ms.

For example, the ozone water is irradiated with ultraviolet light (UV-A), the ozone water is brought into contact with titanium oxide irradiated with ultraviolet light (UV-C), or hydrogen peroxide and / or peracetic acid are used. Hydroxy radicals can be generated by mixing ozone with a kind of aqueous solution. However, in practice, in the method using ultraviolet light, it is difficult to transmit light due to food-borne dirt and water-soluble substances, and since the hydroxyl radical is localized in a part of the aqueous solution, a sufficient sterilizing effect is obtained. Since an excessive amount of energy and time are required to obtain the above, a method of mixing ozone with an aqueous solution of both or any one of hydrogen peroxide and peracetic acid is preferable. That is, the second of the gist of the present invention is to sterilize food by contacting the food with an aqueous solution containing hydroxy radicals obtained by mixing ozone with both or any one aqueous solution of hydrogen peroxide and peracetic acid. Is to provide a way.

[0010] Ozone in the present invention is a component in which three oxygen atoms are bonded, and is, for example, contained in a trace amount in seawater irradiated with sunlight. The method for producing ozone may be any known method, such as irradiating a composition containing oxygen with ultraviolet rays, generating an electric spark in an atmosphere of the composition containing oxygen, or generating plasma by generating plasma. Can be done. Since it is effective to increase the ozone concentration in order to enhance the sterilizing effect, it is preferable to increase the oxygen concentration in the composition containing oxygen. For example, using oxygen gas, using gas whose oxygen concentration is increased using a membrane separation device, adsorption separation device, compression separation device, or the like, or using water with high oxygen concentration by electrolyzing water, It is good to generate ozone. In particular, since the apparatus is simple, it is preferable to generate ozone using oxygen gas or water having a high oxygen concentration obtained by electrolyzing water.

In the present invention, the method of mixing both ozone and one or both of hydrogen peroxide and peracetic acid with an aqueous solution is characterized by adding a commercially available aqueous solution of hydrogen peroxide or an aqueous solution of peracetic acid or a mixture thereof to water and diluting it. This is achieved by mixing and dissolving ozone into the obtained aqueous solution using a known gas-liquid mixing device. Although the gas-liquid mixing device is not particularly limited, it is preferable to forcibly mix ozone rather than simply bubbling due to its low solubility in water, and a porous structure or a nozzle installed in the liquid is preferable. Examples of the method include injecting ozone more, drawing ozone into a liquid in a fluid state by a venturi, and mixing using a mechanical stirring device or a dispersion device. Here, the higher the ozone concentration, the better, but usually 1 to 100
If the concentration is ppm, hydroxy radicals effective for sterilization can be generated. Preferably 1 to 40 pp
m, a more preferred concentration is 5 to 20 ppm.

It is sufficient that the mixing ratio of ozone to both or one or both of hydrogen peroxide and peracetic acid is 1 mol to 10 mol or more. However, if the amount is excessive, the food may be discolored due to hydrogen peroxide or peracetic acid, or the flavor may change, and the value of the product may decrease. Therefore, a preferable mixing ratio of ozone to both or one or both of hydrogen peroxide and peracetic acid is 1 mole to 1 mole.
The range is from 0 mole to 10 moles to 1 mole. That is, the third aspect of the present invention is obtained by mixing ozone with a food in an aqueous solution containing both hydrogen peroxide and peracetic acid or any one of them in a mixing ratio of 1 mol to 10 mol to 10 mol to 1 mol. To provide a method for sterilizing food by contacting an aqueous solution containing a hydroxy radical. Also, as the temperature of the aqueous solution increases, the solubility of ozone decreases,
70 ° C. or lower is preferable, and 62 ° C. or lower is more preferable.
~ 20 ° C is most preferred. In addition, since the lifetime of the hydroxy radical is very short, it is not reasonable to prepare an aqueous solution containing the hydroxy radical and then contact the food with food. Therefore, a method of mixing ozone with the aqueous solution and the food in contact with each other is preferred.

A fourth aspect of the present invention is to provide a food, which is subjected to a physical treatment selected from brushing, showering, and vibration energy, in a step of contacting the food with an aqueous solution containing a hydroxyl radical in a step of contacting the food with the aqueous solution. It is to provide a method of sterilization. That is, the aqueous solution containing hydroxyl radicals cannot reach the bacteria effectively in a state where the bacteria to be sterilized are covered with organic matter,
The sterilization effect can be improved by using a brush and a shower together or by applying vibration energy. In addition, when air bubbles are generated on the surface due to food or pores having a water-repellent surface, an effective aqueous solution containing hydroxyl radicals cannot reach the target as it is, so that effective sterilization cannot be performed. Effective sterilization can be carried out by using together or applying vibration energy.

The brush in the present invention is a pipe, a flat plate,
A rod-shaped structure in which a large number of fibers are arranged.The brush is rotated or vibrated, the food is moved, or both the brush and the food are moved. It rubs the surface. Here, it is also effective to cut out the tip of the brush so that it always keeps a right angle to the target, depending on the shape of the target, and to give the brush a certain angle in consideration of the moving speed of the target. It may be inclined, and it is also effective to arrange a plurality of brushes in a series. Further, the shower in the present invention is a method for more efficiently disinfecting by colliding an aqueous solution containing a hydroxyl radical with food at a high speed. The shower may be performed not only in the air but also in the liquid.

[0015] In the present invention, the method of imparting vibration energy means that an aqueous solution containing a hydroxyl radical has a frequency of several Hz to
This is achieved by immersing a vibration plate to which vibration having a frequency of several hundred kHz is applied. Alternatively, a fluid may be blown at a high speed to generate cavitation, thereby generating vibration secondary. The vibration frequency is preferably 10 Hz to 200 Hz or 10 kHz to 100 kHz, and is preferably 10 Hz.
To 60 Hz or 20 kHz to 50 kHz is more preferable, and 20 Hz to 60 Hz is most preferable. Also,
The diaphragm can be made of a material such as metal, synthetic resin, or rubber. Titanium, titanium alloy, nickel,
Nickel alloy, aluminum, copper, copper alloy, iron and stainless steel can be exemplified. The thickness of the diaphragm is preferably small in order to efficiently transmit vibrations to the aqueous solution, but rigidity is required.
mm is preferred. If necessary, a plurality of diaphragms or a plurality of vibration generators may be provided.

Since the aqueous solution containing a hydroxy radical of the present invention is inactivated when a high concentration of dihydrogen phosphate ion or hydrogen phosphate ion is present, it is preferable that divalent metal ions such as calcium ions coexist. In addition, since high-concentration organic substances also consume hydroxyl radicals, it is preferable that the aqueous solution be appropriately replaced or an additional aqueous solution is supplied so as to overflow, so that the concentration of the organic substance in the aqueous solution does not increase.

To further enhance the bactericidal effect, acetic acid, malic acid, citric acid, gluconic acid, tartaric acid, lactic acid, phytic acid, fumaric acid, adipic acid, oxalic acid, bromic acid, chloric acid, hypochlorous acid, boric acid , Cinnamic acid, benzoic acid or its esters, chlorobenzoic acid or its esters, hydroxybenzoic acid or its esters, salicylic acid, sorbic acid, etc., and their sodium, potassium, calcium, magnesium, etc. salts , Sodium hydroxide, potassium hydroxide, ammonia, alkaline substances such as calcium hydroxide, alkyltrimethylammonium chloride, alkyltrimethylammonium bromide, cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, alkyldimethylethylamine Ammonium chloride, alkyldimethylethylammonium bromide, cetyldimethylethylammonium chloride, octadecenyldimethylethylammonium bromide, octadecyldimethylethylammonium bromide, methyldodecylbenzyltrimethylammonium chloride, alkyldimethylbenzylammonium chloride, lauryldimethylbenzylammonium chloride, cetyl Dimethylbenzylammonium chloride, octadecyldimethylbenzylammonium chloride, alkyldimethyl-3,4-dichlorobenzylammonium chloride,
Dimethylphenylbenzylammonium chloride, myristo-amino-propyl-dimethylbenzylammonium chloride, diisobutyl-phenoxy-ethoxyethyldimethylbenzylammonium chloride, diisobutyl-cresoxy-ethoxy-ethyldimethylbenzylammonium chloride, laurylpyridinium chloride, cetylpyridinium chloride, polyalkyl 4th such as naphthalene methyl pyridinium chloride
Grade ammonium salt, dodecyl diaminoethyl glycine hydrochloride, dodecyl glycine, dodecyl amino ethyl glycine, dodecyl dimethyl benzyl ammonium chloride and other amphoteric surfactants, sodium laurate, potassium laurate, ammonium laurate, alkylolamine laurate, stearin Sodium salt, potassium stearate, ammonium stearate, alkylolamine stearate, sodium myristate,
Potassium myristate, ammonium myristate, alkylolamine amine myristate, sodium palmitate, potassium palmitate, ammonium palmitate, alkylolamine amine palmitate, sodium oleate, potassium oleate, ammonium oleate, alkylol oleate Soaps such as amine salts, sodium sulfates of branched alkylbenzenes, sodium sulfates of linear alkylbenzenes, sodium sulfates of higher alcohols, sodium sulfates of α-olefins, sodium sulfates of alkanes, sodium sulfates of polyoxyethylene adducts Salts, anionic surfactants such as fatty acid amide alkyl sulfated sodium salts, glycerin fatty acid esters, polyglycerin fatty acid esters, sorbitan fatty acid esters, Sugar fatty acid ester, propylene glycol fatty acid ester, fatty acid polyoxyethylene ether, higher alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, sorbitan fatty acid ester polyoxyethylene ether, castor oil polyoxyethylene ether, polyoxypropylene polyoxyethylene ether, etc. Nonionic surfactants such as enjusaponin, soybean saponin, enzyme-treated soybean saponin, tea seed saponin, beet saponin, yucca saponin, quillaja saponin and other saponins, imazalil, orthophenylphenol, sodium orthophenylphenol, diphenyl, thiabendazole and the like A fungicide may be added.

[0018]

EXAMPLES Example 1 Escherichia coli (ATCC-867)
7) and (ATCC-43895), Salmonel
la enteritidis (ATCC-1307)
6), Bacillus cereus (ATCC-1)
1778), Bacillus stearother
mophilus (ATCC-7953), Bacil
rus subtilis (ATCC-6051) was isolated from the Heart Infusion Broth (D
(ifco), at 37 ° C. for 24 hours, and then centrifugally washed twice (6000 rpm, 30 minutes) with sterile distilled water by a cooling centrifuge to obtain a washed bacterial solution.

[0019]

[Table 1]

Example 2 1 part of the washed bacterial solution obtained in Example 1 was added to 9 parts of the aqueous solution having the composition shown in Table 1, and treated at the temperature shown in Table 2 for 0, 1, 3, 5 minutes. Each bacterial count was measured, and the results are shown in Tables 2 and 3 as logarithms.

[0021]

[Table 2]

[0022]

[Table 3]

Comparative Example 1 Using the aqueous solution having the composition shown in Table 1, a test was carried out in the same manner as in Example 2, and the results are shown in Tables 4 and 5 as logarithms.

[0024]

[Table 4]

[0025]

[Table 5]

Example 3 A commercial cabbage was cut into shreds and 10 g of the cabbage was used in Example 1.
1 in 1000 g of tap water containing 10 g of the washed bacterial solution obtained in
After immersion for 0 minutes, water is sufficiently removed. Furthermore, after treatment with an aqueous solution having the composition shown in Table 1 for 0, 1, 3, and 5 minutes, each was homogenized, and the number of bacteria was measured by a conventional method using these as samples. Tables 6 and 7 show the results as logarithms.

[0027]

[Table 6]

[0028]

[Table 7]

Comparative Example 2 A test was conducted in the same manner as in Example 3 except that an aqueous solution having the composition shown in Table 1 was used. The results are shown in Tables 6 and 7 as logarithms.

Example 4 A commercially available egg with a shell was treated with an aqueous solution having the composition shown in Table 1 at the temperature shown in Table 1 for 0, 1, 3, and 5 minutes, and then the eggshell surface was wiped and inspected. Then, the number of bacteria was measured and the results are shown in Tables 8 and 9 as logarithms.

[0031]

[Table 8]

[0032]

[Table 9]

Comparative Example 3 A test was conducted in the same manner as in Example 3 except that the aqueous solution having the composition shown in Table 1 was used. The results are shown in Tables 8 and 9 as logarithms. Embodiments and objects of the present invention are as follows.

(1) A method for sterilizing food, which comprises contacting the food with an aqueous solution containing a hydroxyl radical. (2) Hydroxy radicals generate ultraviolet rays (UV
The sterilization method according to the above (1), wherein the hydroxyl radical is a reaction radical produced by irradiation with -A). (3) Hydroxyl radical is converted to ozone water and ultraviolet (UV)
The sterilization method according to the above (1), wherein the hydroxyl radical is a reaction radical generated by contacting the titanium oxide irradiated with -C). (4) The sterilization method according to the above (1), wherein the hydroxy radical is a hydroxy radical generated by mixing ozone with an aqueous solution of hydrogen peroxide. (5) Hydroxy radical is added to an aqueous solution of hydrogen peroxide
The sterilization method according to the above (1), wherein the hydroxyl radical is a reaction generated by mixing ozone at a ratio of 10 moles to 10 moles to 1 mole per mole.

(6) The sterilization method according to the above (1), wherein the hydroxy radical is a hydroxy radical produced by mixing ozone with an aqueous solution of peracetic acid. (7) The sterilization method according to the above (1), wherein the hydroxy radical is a hydroxy radical produced by mixing ozone with an aqueous solution of peracetic acid at a ratio of 1 mol: 10 mol to 10 mol: 1 mol. (8) The sterilization method according to the above (1), wherein the hydroxy radical is a hydroxy radical produced by mixing ozone with an aqueous solution of both hydrogen peroxide and peracetic acid. (9) The above-mentioned (1), wherein the hydroxy radical is produced by mixing ozone with an aqueous solution of both hydrogen peroxide and peracetic acid at a ratio of 1 mol: 10 mol to 10 mol: 1 mol. The sterilization method described. (10) The sterilization method according to any one of (2) to (6), wherein the ozone is ozone generated using oxygen gas.

(11) The sterilization method according to any one of (2) to (6) above, wherein the ozone is ozone generated using air having an increased oxygen concentration using a membrane separation device. (12) The ozone is ozone generated by using air having an increased oxygen concentration using an adsorption separation device.
(6) The sterilization method according to any of the above. (13) The sterilization method according to any one of (2) to (6), wherein the ozone is ozone generated using water having an increased oxygen concentration obtained by electromechanical decomposition. (14) The sterilization method according to any one of (2) to (10), wherein the ozone concentration is 1 to 100 ppm. (15) The above (2), wherein the ozone concentration is 1 to 40 ppm.
To (10).

(16) The sterilization method according to any one of (2) to (10), wherein the ozone concentration is 2 to 20 ppm. (17) The above (1) to (10), wherein the temperature of the aqueous solution is 70 ° C. or lower.
(16) The sterilization method according to any of the above. (18) The above (1) to (6), wherein the temperature of the aqueous solution is 62 ° C. or lower.
(16) The sterilization method according to any of the above. (19) The sterilization method according to any one of (1) to (16), wherein the temperature of the aqueous solution is 5 to 20 ° C or lower. (20) The sterilization method according to any one of (1) to (20), wherein in the step of contacting the food with an aqueous solution containing a hydroxyl radical, the food immersed in the aqueous solution is subjected to a brushing treatment.

(21) The step (1), wherein the step of contacting the food with an aqueous solution containing a hydroxyl radical comprises subjecting the food immersed in the aqueous solution to a showering treatment.
To (20). (22) The sterilization method according to any one of (1) to (20) above, wherein in the step of contacting the food with an aqueous solution containing a hydroxyl radical, the food immersed in the aqueous solution is subjected to vibration energy treatment. (23) The method according to (2), wherein the vibration frequency is 10 to 200 Hz.
The sterilization method according to 2). (24) The method according to (2), wherein the vibration frequency is 10 to 60 Hz.
The sterilization method according to 2). (25) The method according to (2), wherein the vibration frequency is 20 to 60 Hz.
The sterilization method according to 2). (26) The sterilization method according to (22), wherein the vibration frequency is 10 to 100 kHz. (27) The method according to (2), wherein the vibration frequency is 20 to 50 kHz.
The sterilization method according to 2).

[0039]

As described above, according to the constitution of the present invention, the hydroxyl radical is strongly killed not only for normal bacteria such as Salmonella and Escherichia coli but also for bacteria which are resistant to oxygen stress such as Bacillus. It became clear that it had an effect. Therefore, the food sterilization method according to the present invention, which involves contacting an aqueous solution containing a hydroxyl radical with the food, enables the food to be sterilized without deteriorating the quality of the food.

Claims (6)

[Claims] 1. A method for sterilizing food, comprising bringing an aqueous solution containing a hydroxyl radical into contact with the food. 2. The sterilization method according to claim 1, wherein the hydroxy radical is a hydroxy radical produced by mixing ozone with an aqueous solution of hydrogen peroxide and / or at least one of peracetic acid. 3. The sterilization method according to claim 2, wherein the mixing ratio of ozone and / or one or both of hydrogen peroxide and peracetic acid is from 1 mol to 10 mol to 10 mol to 1 mol. 4. A step of contacting the food with an aqueous solution containing a hydroxyl radical, wherein the food immersed in the aqueous solution is subjected to one or more physical treatments selected from brushing, showering, and vibrational energy. The sterilization method according to claim 1. 5. The sterilization method according to claim 1, wherein the food is a chicken egg. 6. The sterilization method according to any one of 1 to 5, wherein the target of sterilization is a spore bacterium.