Growth inhibitor for thermotolerant acidophilic bacteria and method for inhibiting the growth of thermotolerant acidophilic bacteria

Abstract

This invention provides a heat-resistant acidophilic bacteria proliferation inhibitor and a method for inhibiting heat-resistant acidophilic bacteria proliferation in drinks. This invention relates to, e.g., a heat-resistant acidophilic bacteria proliferation inhibitor containing an active ingredient constituted by a 3-hydroxybutyric acid or a salt thereof.

Description

[Technical Field]

[0001] The present invention relates to a growth inhibitor for thermotolerant acidophilic bacteria. The present invention also relates to a growth inhibitor for thermotolerant acidophilic bacteria, and a method for inhibiting the growth of thermotolerant acidophilic bacteria. [Background technology]

[0002] For commercially available beverages, it is important to prevent microbial contamination and improve shelf life. For example, thermotolerant acidophilic bacteria such as Alicyclobacillus acidoterrestris convert components in fruit juice into guaiacol, a substance that causes an unpleasant odor. If they proliferate, they can cause a deterioration in the quality of food and beverages.

[0003] 3-hydroxybutyrate (3HB) is a type of short-chain fatty acid that is produced as an energy source when glucose in the body is depleted, such as during carbohydrate restriction or strenuous exercise. It has been reported that 3-hydroxybutyrate has various physiological functions in addition to its function as an energy source. For example, Patent Document 1 describes an inhibitor of collagenase MMP1 and MMP3 production that contains R-3-hydroxybutyrate as an active ingredient. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-158897 Summary of the Invention [Problem to be solved by the invention]

[0005] Thermotolerant acidophilic bacteria are heat-resistant and can grow under acidic conditions, and therefore have antibacterial activity against thermotolerant acidophilic bacteria. Components that can be used in foods and beverages are useful in the food and beverage industry.

[0006] An object of the present invention is to provide an inhibitor of the growth of thermotolerant acidophilic bacteria and a method for inhibiting the growth of thermotolerant acidophilic bacteria in beverages. [Means for solving the problem]

[0007] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that 3-hydroxybutyric acid or a salt thereof exhibits a growth inhibitory effect on thermotolerant acidophilic bacteria. It has not been reported that 3-hydroxybutyric acid or a salt thereof has an antibacterial effect.

[0008] That is, although not limited thereto, the present invention relates to the following thermotolerant acidophilic bacteria growth inhibitor and method for inhibiting the growth of thermotolerant acidophilic bacteria in beverages. [1] A growth inhibitor of thermotolerant acidophilic bacteria, comprising 3-hydroxybutyric acid or a salt thereof as an active ingredient. [2] The thermotolerant acidophilic bacteria growth inhibitor according to [1] above, which is for use in beverages. [3] The growth inhibitor of thermotolerant acidophilic bacteria according to the above [1] or [2], wherein the thermotolerant acidophilic bacterium is Alicyclobacillus acidoterrestris. [4] A method for inhibiting the growth of thermotolerant acidophilic bacteria in a beverage, comprising adding 3-hydroxybutyric acid or a salt thereof to the beverage so that the concentration of 3-hydroxybutyric acid or a salt thereof in the beverage is 0.2% by weight or more in terms of 3-hydroxybutyric acid. [5] The method according to [4] above, wherein the pH of the beverage is adjusted to 6.5 or less. [6] The method according to [4] or [5] above, wherein the pH of the beverage is adjusted to 2.5 to 4.6. [7] The method according to any one of [4] to [6] above, wherein the thermotolerant acidophilic bacterium is Alicyclobacillus acidoterrestris. [8] The method according to any one of [4] to [7] above, wherein the beverage is a tea beverage, a coffee beverage, a non-alcoholic beer-flavored beverage, a carbonated beverage, a functional beverage, a fruit or vegetable beverage, a dairy beverage, a soy milk beverage, or a flavored water. [9] The method according to any one of [4] to [8] above, wherein the beverage is a non-alcoholic beer-flavored beverage, a functional beverage, a carbonated beverage, or a fruit / vegetable beverage.

[10] Use of 3-hydroxybutyric acid or a salt thereof to inhibit the growth of thermotolerant acidophilic bacteria.

[11] A beverage comprising the thermotolerant acidophilic bacteria growth inhibitor according to any one of [1] to [3] above.

[12] The beverage according to

[11] above, wherein the concentration of 3-hydroxybutyric acid or a salt thereof is 0.2% by weight or more in terms of 3-hydroxybutyric acid. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an inhibitor of the growth of thermotolerant acidophilic bacteria. Also, according to the present invention, it is possible to provide a method for inhibiting the growth of thermotolerant acidophilic bacteria in a beverage. DETAILED DESCRIPTION OF THE INVENTION

[0010] The growth inhibitor of thermotolerant acidophilic bacteria of the present invention contains 3-hydroxybutyric acid or a salt thereof. The growth inhibitor of thermotolerant acidophilic bacteria of the present invention contains 3-hydroxybutyric acid or a salt thereof as an active ingredient. 3-hydroxybutyric acid or a salt thereof has an antibacterial effect against thermotolerant acidophilic bacteria, and therefore can be used to inhibit the growth of thermotolerant acidophilic bacteria.

[0011] 3-hydroxybutyric acid is a type of short-chain fatty acid and is also called β-hydroxybutyric acid. In the present invention, 3-hydroxybutyric acid may be any of the R-form (R-3 hydroxybutyric acid), the S-form (S-3 hydroxybutyric acid), and a mixture of the R- and S-forms. In one embodiment, 3-hydroxybutyric acid is preferably a mixture of R-3 hydroxybutyric acid and S-3 hydroxybutyric acid.

[0012] The salt of 3-hydroxybutyric acid is not particularly limited as long as it is a pharmacologically acceptable salt or a salt acceptable for use in foods and beverages, and examples thereof include metal salts such as sodium salt, potassium salt, magnesium salt, and calcium salt; basic amino acid salts such as arginine salt; and the like.

[0013] The origin and production method of 3-hydroxybutyric acid or a salt thereof are not particularly limited, and they may be chemically synthesized products or products produced by fermentation or enzymatic methods. 3-hydroxybutyric acid and salts thereof are commercially available, and commercially available products can also be used.

[0014] The content of 3-hydroxybutyric acid or a salt thereof in the thermotolerant acidophilic bacterial growth inhibitor of the present invention can be appropriately set. The content of 3-hydroxybutyric acid or a salt thereof in the thermotolerant acidophilic bacterial growth inhibitor of the present invention is, for example, preferably 0.2% by weight or more, more preferably 0.5% by weight or more, calculated as 3-hydroxybutyric acid. Furthermore, the content of 3-hydroxybutyric acid or a salt thereof in the thermotolerant acidophilic bacterial growth inhibitor may be, for example, 40% by weight or less, or 20% by weight or less, calculated as 3-hydroxybutyric acid. The thermotolerant acidophilic bacterial growth inhibitor of the present invention may contain a solvent, an excipient, etc.

[0015] Examples of thermotolerant acidophilic bacteria include bacteria of the genus Alicyclobacillus, such as Alicyclobacillus acidoterrestris and Alicyclobacillus acidifilus. Among these, Alicyclobacillus acidoterrestris is more preferred as the thermotolerant acidophilic bacterium. 3-hydroxybutyric acid and its salts exhibit antibacterial activity against the above-mentioned thermotolerant acidophilic bacteria. Alicyclobacillus acidoterrestris is a Gram-positive, spore-forming bacterium belonging to the genus Alicyclobacillus. In one embodiment, the growth inhibitor of thermotolerant acidophilic bacteria of the present invention can be suitably used to inhibit the growth of Alicyclobacillus acidoterrestris.

[0016] The thermotolerant acidophilic bacteria growth inhibitor of the present invention is used to inhibit the growth of thermotolerant acidophilic bacteria in foods and beverages. For example, by adding the thermotolerant acidophilic bacteria growth inhibitor of the present invention to foods and beverages, the growth of thermotolerant acidophilic bacteria in the foods and beverages can be inhibited. The objects for which the thermotolerant acidophilic bacteria growth inhibitor of the present invention is used are not limited to foods and beverages. The thermotolerant acidophilic bacteria growth inhibitor of the present invention can also be added to pharmaceuticals, quasi-drugs, etc., for example, to inhibit the growth of thermotolerant acidophilic bacteria in pharmaceuticals, quasi-drugs, etc. By using 3-hydroxybutyric acid or a salt thereof, for example, foods and beverages, pharmaceuticals, quasi-drugs, etc. in which the growth of thermotolerant acidophilic bacteria is inhibited can be obtained. The above objects are preferably liquids. The foods and beverages are preferably beverages (liquid beverages).

[0017] In one embodiment, the thermotolerant acidophilic bacteria growth inhibitor of the present invention is suitable for use in inhibiting the growth of thermotolerant acidophilic bacteria in beverages. In one embodiment, the thermotolerant acidophilic bacteria growth inhibitor of the present invention is preferably a thermotolerant acidophilic bacteria growth inhibitor for beverages. The beverage preferably has a pH of 6.5 or less. This is because thermotolerant acidophilic bacteria generally prefer acidic conditions. Adding 3-hydroxybutyric acid or a salt thereof to a beverage with a pH of 6.5 or less can effectively inhibit the growth of thermotolerant acidophilic bacteria in the beverage. The pH of the beverage is more preferably 6.4 or less, even more preferably 2.0 to 4.6, and particularly preferably 2.5 to 4.0. Use of the thermotolerant acidophilic bacteria growth inhibitor of the present invention can effectively inhibit the growth of thermotolerant acidophilic bacteria in beverages with a pH in the above range. Use of the thermotolerant acidophilic bacteria growth inhibitor of the present invention can inhibit the growth of thermotolerant acidophilic bacteria, for example, in beverages with a pH in the above range, more effectively than when 3-hydroxybutyric acid or a salt thereof is not used. In this specification, pH is the pH at 25° C. The pH can be measured using a commercially available pH measuring device.

[0018] The amount of the thermotolerant acidophilic bacteria growth inhibitor of the present invention used is not particularly limited, as long as it is an amount that can achieve the effect of inhibiting the growth of thermotolerant acidophilic bacteria in foods, beverages, etc. For example, when the thermotolerant acidophilic bacteria growth inhibitor of the present invention is used in a beverage, the amount is preferably such that the concentration of 3-hydroxybutyric acid or a salt thereof in the beverage is, in terms of 3-hydroxybutyric acid equivalent, is preferably 0.2 wt % or more, more preferably 0.3 wt % or more, and even more preferably 0.4 wt % or more. It is expected that the greater the amount of 3-hydroxybutyric acid or a salt thereof, the greater the effect of inhibiting the growth of thermotolerant acidophilic bacteria. On the other hand, from the viewpoint of the flavor and taste of the beverage, the amount of the thermotolerant acidophilic bacteria growth inhibitor used is preferably such that the concentration of 3-hydroxybutyric acid or a salt thereof in the beverage is, in terms of 3-hydroxybutyric acid equivalent, is preferably 5 wt % or less, more preferably 4 wt % or less, and even more preferably 3 wt % or less. In one aspect, the amount of the thermotolerant acidophilic bacteria growth inhibitor of the present invention used in a beverage is preferably an amount such that the concentration of 3-hydroxybutyric acid or a salt thereof in the beverage is, in terms of 3-hydroxybutyric acid, preferably 0.2 to 5 wt %, more preferably 0.3 to 4 wt %, and even more preferably 0.4 to 3 wt %. In one aspect, when inhibiting the growth of thermotolerant acidophilic bacteria in a liquid such as a beverage, the thermotolerant acidophilic bacteria growth inhibitor is preferably used so that the concentration of 3-hydroxybutyric acid or a salt thereof in the liquid is within the above range. With respect to 3-hydroxybutyric acid or a salt thereof, the amount (or concentration) converted to 3-hydroxybutyric acid means, in the case of 3-hydroxybutyric acid, the amount (or concentration) of 3-hydroxybutyric acid. In the case of a salt of 3-hydroxybutyric acid, it means the amount (or concentration) of 3-hydroxybutyric acid with the same number of moles as the salt.

[0019] The concentration of 3-hydroxybutyric acid or a salt thereof can be measured by a high performance liquid chromatograph (HPLC) (for example, the LC-10 series manufactured by Shimadzu Corporation). The measurement conditions can be as follows. Column: SHIM-PACK SCR-102H (8 mm ID x 300 mm L) (Shimadzu Corporation) Mobile phase: A mixture of water, p-toluenesulfonic acid, EDTA, and Bis-Tris Flow rate: 0.8ml / min Column temperature: 40℃ Detection: Electrical conductivity (Polarity set to +) Analysis time: 30 minutes

[0020] The present invention also encompasses a method for inhibiting the growth of thermotolerant acidophilic bacteria in a beverage. The method for inhibiting the growth of thermotolerant acidophilic bacteria in a beverage of the present invention comprises adding 3-hydroxybutyric acid or a salt thereof to the beverage so that the concentration of 3-hydroxybutyric acid or a salt thereof in the beverage is 0.2% by weight or more in terms of 3-hydroxybutyric acid. The preferred embodiment of 3-hydroxybutyric acid or a salt thereof is the same as that of the thermotolerant acidophilic bacteria growth inhibitor of the present invention described above.

[0021] In the method of the present invention, 3-hydroxybutyric acid or a salt thereof is added to a beverage so that the concentration, calculated as 3-hydroxybutyric acid, is 0.2% by weight or more. When the concentration of 3-hydroxybutyric acid or a salt thereof in the beverage is 0.2% by weight or more, calculated as 3-hydroxybutyric acid, the growth of thermotolerant acidophilic bacteria in the beverage can be inhibited. In the method of the present invention, it is preferable to add 3-hydroxybutyric acid or a salt thereof to a beverage in an amount such that the concentration of 3-hydroxybutyric acid or a salt thereof in the beverage is preferably 0.3 wt % or more, more preferably 0.4 wt % or more, calculated as 3-hydroxybutyric acid. Adding 3-hydroxybutyric acid or a salt thereof to a beverage in the amounts described above can more effectively inhibit the growth of thermotolerant acidophilic bacteria in the beverage. Furthermore, from the viewpoint of the flavor and taste of the beverage, it is preferable to add 3-hydroxybutyric acid or a salt thereof to a beverage in an amount such that the concentration of 3-hydroxybutyric acid or a salt thereof in the beverage is preferably 5 wt % or less, more preferably 4 wt % or less, and even more preferably 3 wt % or less, calculated as 3-hydroxybutyric acid. In one aspect, in the method of the present invention, it is preferable to add 3-hydroxybutyric acid or a salt thereof to a beverage so that the concentration of 3-hydroxybutyric acid or a salt thereof in the beverage is preferably 0.2 to 5 wt %, more preferably 0.3 to 4 wt %, and even more preferably 0.4 to 2 wt %, calculated as 3-hydroxybutyric acid. In the method of the present invention, it is sufficient that the final concentration of 3-hydroxybutyric acid or a salt thereof in the beverage is the above-mentioned concentration. 3-hydroxybutyric acid or a salt thereof may be added during the production of the beverage.

[0022] The method for inhibiting the growth of thermotolerant acidophilic bacteria of the present invention is suitable for use as a method for inhibiting the growth of thermotolerant acidophilic bacteria in beverages with a pH of 6.5 or less. The use of 3-hydroxybutyric acid or a salt thereof can effectively inhibit the growth of thermotolerant acidophilic bacteria in beverages with a pH of 6.5 or less. The pH of the beverage is preferably 6.4 or less, more preferably 2.0 to 4.6, and particularly preferably 2.5 to 4.0. According to the manufacturing standards set forth in the Food Sanitation Act, beverages with a pH of less than 4.0 must be heat-sterilized at 65°C for 10 minutes or equivalent conditions, and beverages with a pH of 4.0 or more but less than 4.6 must be heat-sterilized at 85°C for 30 minutes or equivalent conditions. However, such heat-sterilization treatments may still pose a risk of microbial contamination by thermotolerant acidophilic bacteria. The method for inhibiting the growth of thermotolerant acidophilic bacteria of the present invention can effectively inhibit the growth of thermotolerant acidophilic bacteria in beverages with a pH of preferably 6.5 or less, more preferably 6.4 or less, even more preferably a pH of 2.0 to 4.6, and particularly preferably a pH of 2.5 to 4.0, compared to when 3-hydroxybutyric acid or a salt thereof is not used.

[0023] In the method for inhibiting the growth of thermotolerant acidophilic bacteria in a beverage of the present invention, the pH of the beverage may be adjusted as necessary. In the method of the present invention, the pH of the beverage may be adjusted to 6.5 or less. In one aspect, the method for inhibiting the growth of thermotolerant acidophilic bacteria in a beverage of the present invention may include a step of adjusting the pH of the beverage to 6.5 or less. The method for inhibiting the growth of thermotolerant acidophilic bacteria in a beverage of the present invention may include a step of adjusting the pH of the beverage to 6.4 or less, 2.0 to 4.6, or 2.5 to 4.0. In one aspect, the pH of the beverage may be adjusted to less than 4.6, or less than 4.0. The final pH of the beverage may be any of the above. The pH may be adjusted before or after the addition of 3-hydroxybutyric acid or a salt thereof. In one embodiment of the method of the present invention, 3-hydroxybutyric acid or a salt thereof may be added to a beverage having a pH of 6.5 or less. In the method of the present invention, the pH of the beverage to which 3-hydroxybutyric acid or a salt thereof has been added may be adjusted to 6.5 or less, if necessary. The pH can be adjusted by a known method, for example, by adding a pH adjuster as necessary.

[0024] The method of inhibiting the growth of thermotolerant acidophilic bacteria in a beverage of the present invention may include a step of heating the beverage. The beverage may be heated before or after the addition of 3-hydroxybutyric acid or a salt thereof, but is preferably heated after the addition. The heating conditions are not particularly limited, but may be, for example, 65 to 130°C, preferably 85 to 120°C, for 10 to 40 minutes. However, as long as a bactericidal value equivalent to that obtained under the above conditions is obtained, heating at an appropriate temperature for a few seconds, for example, 5 to 30 seconds, is also acceptable.

[0025] In the method for inhibiting the growth of thermotolerant acidophilic bacteria in a beverage, the thermotolerant acidophilic bacteria and preferred embodiments thereof are the same as those described above. The thermotolerant acidophilic bacteria are preferably Alicyclobacillus acidoterrestris. The method of the present invention can be suitably used to inhibit the growth of the above microorganisms in a beverage.

[0026] The thermotolerant acidophilic bacteria growth inhibitor and thermotolerant acidophilic bacteria growth inhibitor method of the present invention can be used in beverages such as non-alcoholic beverages and alcoholic beverages, with non-alcoholic beverages being preferred. In this specification, the term "non-alcoholic beverage" refers to a beverage with an ethanol concentration of 1.2 v / v% or less, preferably 1.0 v / v% or less, and more preferably 0.5 v / v% or less. Preferred examples of non-alcoholic beverages include tea beverages, coffee beverages, non-alcoholic beer-flavored beverages, carbonated beverages, functional beverages, fruit and vegetable beverages, dairy beverages, soy milk beverages, and flavored water. The thermotolerant acidophilic bacteria growth inhibitor and thermotolerant acidophilic bacteria growth inhibitor method of the present invention are preferably used in non-alcoholic beer-flavored beverages, functional beverages, carbonated beverages, or fruit and vegetable beverages. This is because these beverages typically have a pH of 6.5 or less, which increases the possibility of thermotolerant acidophilic bacteria growing. Among these, functional beverages and fruit and vegetable beverages are more preferred.

[0027] As tea-based beverages, black tea beverages and unsweetened tea beverages are preferred. Examples of unsweetened tea beverages include green tea beverages, oolong tea beverages, barley tea beverages, brown rice tea beverages, Job's tears tea beverages, and unsweetened black tea beverages. As the coffee beverage, packaged coffee and liquid coffee are preferred.

[0028] In this specification, the term "non-alcoholic beer-flavored beverage" refers to a carbonated beverage with a beer-like flavor, which is a non-fermented, non-alcoholic beverage that contains substantially no alcohol. The term "non-alcoholic beer-flavored beverage" does not exclude beverages that contain trace amounts of alcohol that are undetectable.

[0029] As carbonated drinks, cola-flavored drinks, clear carbonated drinks, ginger ale, fruit juice carbonated drinks, dairy carbonated drinks, and sugar-free carbonated drinks are preferred. Examples of functional drinks include sports drinks, energy drinks, health support drinks, and pouch jelly drinks, with sports drinks, energy drinks, and health support drinks being preferred. As the fruit and vegetable beverage, 100% fruit beverage, beverage containing fruit, soft drink with low fruit juice content, fruit beverage containing fruit particles, and pulp beverage are preferred.

[0030] The present invention also encompasses the use of 3-hydroxybutyric acid or a salt thereof for inhibiting the growth of thermotolerant acidophilic bacteria. The present invention also encompasses the use of 3-hydroxybutyric acid or a salt thereof for producing a thermotolerant acidophilic bacteria growth inhibitor. 3-hydroxybutyric acid or a salt thereof can be used as an active ingredient for inhibiting the growth of thermotolerant acidophilic bacteria. In the above use, 3-hydroxybutyric acid or a salt thereof and their preferred aspects are the same as those described above. The subject matter for which 3-hydroxybutyric acid or a salt thereof is used and its preferred aspects are the same as those for which the thermotolerant acidophilic bacteria growth inhibitor is used and its preferred aspects. 3-hydroxybutyric acid or a salt thereof is preferably used to inhibit the growth of thermotolerant acidophilic bacteria, preferably in a liquid, more preferably in a beverage. The beverage and its preferred aspects are the same as those described above. In one embodiment, the concentration of 3-hydroxybutyric acid or a salt thereof in a target substance such as a beverage is preferably 0.2 wt % or more, more preferably 0.2 to 5 wt %, even more preferably 0.3 to 4 wt %, and particularly preferably 0.4 to 3 wt %, calculated as a 3-hydroxybutyric acid concentration. In one embodiment, it is preferable to add 3-hydroxybutyric acid or a salt thereof to the target substance so that the concentration of 3-hydroxybutyric acid or a salt thereof is within the above range. By incorporating the thermotolerant acidophilic bacteria growth inhibitor of the present invention into a beverage, a beverage in which the growth of thermotolerant acidophilic bacteria is inhibited can be obtained. Beverages containing the thermotolerant acidophilic bacteria growth inhibitor are also encompassed by the present invention. The beverage and its preferred embodiments are the same as those described above. The concentration of 3-hydroxybutyric acid or a salt thereof in the beverage is preferably 0.2 wt % or more, more preferably 0.2 to 5 wt %, even more preferably 0.3 to 4 wt %, and particularly preferably 0.4 to 3 wt %, calculated as 3-hydroxybutyric acid.

[0031] In this specification, a numerical range expressed by a lower limit and an upper limit, i.e., "lower limit to upper limit," includes the lower limit and the upper limit. For example, a range expressed by "1 to 2" means 1 or more and 2 or less, including 1 and 2. In this specification, the upper limit and the lower limit may be any combination of ranges. [Example]

[0032] EXAMPLES The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0033] In the following examples, sodium 3-hydroxybutyrate was used as DL-sodium 3-hydroxybutyrate (Sigma-Aldrich) (a mixture of sodium R-hydroxybutyrate and sodium S-hydroxybutyrate (R-:S-isomer molar ratio 50:50), hereinafter referred to as 3HB-Na). The test bacteria used was the thermotolerant acidophilic bacterium Alicyclobacillus acidoterrestris NBRC 108913.

[0034] Example 1 The minimum inhibitory concentration (MIC) of 3HB-Na against test bacteria was measured. (Test Method) The broth dilution method was used. (1) Preparation of test samples 3HB-Na and 6N HCl were mixed to prepare a 3HB-Na solution (3HB-Na concentration: 20% by weight). This 3HB-Na solution was diluted with YSG liquid medium to prepare a sample with a 3HB-Na concentration of 2% by weight. This was then diluted with YSG liquid medium to prepare a 2-fold dilution series of 10 levels, which were used as test samples (Nos. 1 to 10). The 3HB-Na concentrations in the test samples (10 levels, 0.004 to 2% by weight) are listed below. The concentration in parentheses is shown as 3-hydroxybutyric acid equivalent (3HB equivalent). No.1: 2% by weight (3HB conversion: 1.6% by weight), No.2: 1% by weight (3HB conversion: 0.8% by weight), No.3: 0.5% by weight (3HB conversion: 0.4 Weight %), No. 4: 0.25 weight % (3HB conversion: 0.2 weight %), No. 5: 0.125 weight % (3HB conversion: 0.1 weight %), No. 6: 0.063 Weight% (3HB conversion: 0.05 weight%), No.7: 0.031 weight% (3HB conversion: 0.025 weight%), No.8: 0.0l6 weight% (3HB conversion: 0.013 weight%), No.9: 0.008 weight% (3HB conversion: 0.007 weight%), No.10: 0.004 weight% (3HB conversion: 0.003 weight%) YSG liquid medium without 3HB-Na was used as a control.

[0035] (2)pH measurement The pH (25°C) of the test sample was measured using a pH meter (AS600, manufactured by AS ONE Corporation).

[0036] (3) Preparation of test bacterial solution The test bacteria were inoculated onto YSG agar medium and cultured at 45°C for 24 hours. After the culture, the number of bacteria was reduced to 10 using physiological saline. 7 The test bacterial solution was prepared so that the concentration was CFU / mL.

[0037] (4) Inoculation and cultivation of test bacterial solution The test samples (Nos. 1 to 10) prepared above were used as test media. Each test medium was inoculated with a test bacterial solution and cultured at 45°C for 24 hours. Each test sample was tested in triplicate. (5) MIC determination After the incubation, the growth of the test bacteria was observed with the naked eye, and the MIC was determined.

[0038] (result) Table 1 shows the pH measurement results of the test samples. Table 2 shows the MIC measurement results of 3HB-Na against Alicyclobacillus acidoterrestris. In Table 1, a pH 4.0 buffer solution (Nacalai Tesque, Inc.) was used as the control. In the MIC test control, good growth of the test bacteria was observed.

[0039] [Table 1]

[0040] [Table 2]

[0041] The evaluations in Table 2 are based on the results of three tests (n=3) per specimen (test sample). (Judgment criteria) "+": Growth is observed "-": No growth observed

[0042] 3HB-Na inhibited the growth of test bacteria. The MIC of 3HB-Na against the test bacteria was 0.25% by weight (0.2% by weight in terms of 3-hydroxybutyric acid).

[0043] It has been found that 3-hydroxybutyric acid or a salt thereof has an antibacterial effect against thermotolerant acidophilic bacteria, that is, an effect of inhibiting the growth of thermotolerant acidophilic bacteria. [Industrial Applicability]

[0044] The present invention is useful, for example, in the field of food and beverages.

Claims

1. Contains 3-hydroxybutyric acid or a salt thereof as an active ingredient, The thermotolerant acidophilic bacteria growth inhibitor, wherein the salt is at least one selected from the group consisting of sodium salts, potassium salts, magnesium salts, calcium salts and arginine salts.

2. The growth inhibitor of thermotolerant acidophilic bacteria according to claim 1, which is for use in beverages.

3. 3. The growth inhibitor of thermotolerant acidophilic bacteria according to claim 1, wherein the thermotolerant acidophilic bacterium is Alicyclobacillus acidoterrestris.

4. A method for inhibiting the growth of thermotolerant acidophilic bacteria in a beverage, comprising: The method includes a step of adding 3-hydroxybutyric acid or a salt thereof to a beverage so that the concentration of 3-hydroxybutyric acid or a salt thereof in the beverage is 0.2% by weight or more in terms of 3-hydroxybutyric acid, The method for inhibiting the growth of thermotolerant acidophilic bacteria in a beverage, wherein the salt is at least one selected from the group consisting of sodium salts, potassium salts, magnesium salts, calcium salts and arginine salts.

5. 5. The method of claim 4, wherein the pH of the beverage is adjusted to 6.5 or less.

6. The method according to claim 4 or 5, wherein the pH of the beverage is adjusted to 2.5 to 4.

6.

7. 6. The method according to claim 4 or 5, wherein the thermotolerant acidophilic bacterium is Alicyclobacillus acidoterrestris.

8. The method according to claim 4 or 5, wherein the beverage is a tea beverage, a coffee beverage, a non-alcoholic beer-flavored beverage, a carbonated beverage, a functional beverage, a fruit / vegetable beverage, a dairy beverage, a soy milk beverage, or a flavored water.

9. The method according to claim 4 or 5, wherein the beverage is a non-alcoholic beer-flavored beverage, a functional beverage, a carbonated beverage, or a fruit / vegetable beverage.

10. Use of 3-hydroxybutyric acid or a salt thereof for inhibiting the growth of thermotolerant acidophilic bacteria, The use, wherein the salt is at least one selected from the group consisting of sodium salts, potassium salts, magnesium salts, calcium salts and arginine salts.

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