JPH0819387A - Sterilization of food - Google Patents

Abstract

PURPOSE:To efficiently sterilize food without affecting tastes and giving problems such as a bad smell generation by treating the food with UV rays after treating the food with an organic acid and giving high sterilizing effect with synergistic effect of the organic acid and the UV rays. CONSTITUTION:This method for sterilizing food is to treat the food such as sliced boneless ham with a 2-70mM aqueous solution of an organic acid such as acetic acid, fumaric acid, citric acid, succinic acid, malic acid, lactic acid, tartaric acid, gluconic acid, etc., by inoculation, vacuum-seal the food with a multilayer film made of polyvinylidene chloride) by a vacuum sealer and then treat the sealed food with UV rays 5-1200mW.see/cm<12> UV ray density per unit area of the food surface. The food is effectively sterilized without affecting food taste and giving problems such as bad smell generation with a lower value than that of the organic acid concentration in a single treatment or that of UV ray radiation value in the single treatment and with high sterilizing effect owing to synergistic action of the organic acid and the UV ray treatments.

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 foods, and more particularly to a method for sterilizing foods that does not adversely affect the taste and causes no offensive odor.

[0002]

2. Description of the Related Art Generally, foods are contaminated and spoiled by microorganisms, resulting in a significant decrease in food value.
May cause poisoning by pathogenic bacteria. In wide area distribution and mass sales in recent years, it is needless to say that the deterioration of foods is prevented by bacteria, and safe foods are required from the viewpoint of hygiene. Therefore, to improve the shelf life of foods,
Various bacterial methods have been proposed.

For example, Japanese Examined Patent Publication (Kokoku) No. 51-45660 discloses a sterilizing composition which uses an organic acid and an organic acid salt alone or in combination. In addition, Japanese Patent Laid-Open No. 2-60
Japanese Patent No. 543 discloses a method of sterilizing raw meat vacuum-packed with a film packaging material having ultraviolet transparency and heat shrinkability, in which the raw meat is vacuum-packaged with the film packaging material and irradiated with ultraviolet rays, and then the heat of the film packaging material is reduced. A method for sterilizing vacuum-packed raw meat is described, in which the package is treated in a high temperature atmosphere for shrinkage and sterilization.

[0004]

However, in the case of the composition for sterilization described in JP-B-51-45660,
Since a high concentration is required, there is a problem that the taste is adversely affected. Further, the sterilization method described in JP-A-2-60543 is not necessarily a sufficient method. In particular, when the ultraviolet ray dose is 2000 mW · sec / cm ² or more, the bactericidal effect reaches the ceiling, and there is a problem that the ultraviolet ray dose is too strong depending on the object to be sterilized, which causes an offensive odor. The present invention has been made in view of such circumstances, the object thereof is a method of sterilizing foods using a combination of organic acid treatment and ultraviolet treatment, such that an offensive odor is produced without adversely affecting taste. An object of the present invention is to provide an improved food sterilization method that is free from problems.

[0005]

That is, the gist of the present invention resides in a method of sterilizing a food, which comprises treating the food with an organic acid and then treating it with ultraviolet rays.

The present invention will be described in detail below. Examples of the food used in the present invention include beef, pig, bird, sheep, various meat such as fish, ham, sausage, chikuwa,
It is also possible to target processed meat such as kamaboko. In particular,
Meat and processed meat such as ham and sausage are preferably used. On the other hand, examples of the organic acid include acetic acid, fumaric acid, citric acid, succinic acid, malic acid, lactic acid, tartaric acid and gluconic acid. Of these, acetic acid or lactic acid is particularly preferably used.

First, in the sterilization method of the present invention, food is treated with an organic acid. The concentration of the organic acid is usually 1 to 50.
It is selected from the range of 0 mM. However, in the present invention, since an excellent bactericidal effect is achieved by the synergistic action with the ultraviolet treatment described below, the concentration of the organic acid is sufficient in the low concentration range in the above concentration range, and the sterilization of the present invention is performed. In the method, there is no problem that the taste is adversely affected. The concentration of the organic acid is preferably 2 to 70 m
M, particularly preferably 5 to 40 mM. The treatment with an organic acid is performed by various methods such as coating, spraying and dipping.

In the sterilization method of the present invention, the food treated with an organic acid is treated with ultraviolet rays. The ultraviolet treatment is preferably carried out after the organic acid treatment and before packaging the food with a film. This is because there is a risk that the bacteria will adhere to the food treated with the organic acid again in the line before being treated with ultraviolet rays, and the effect of ultraviolet ray treatment will be reduced.

The film may be any of those generally used for food packaging. For example, polyvinyl chloride,
Polyvinylidene chloride, polyvinyl alcohol, ethylene / vinyl alcohol copolymer, ethylene / vinyl acetate copolymer, nylon, polyethylene, ionomer, polypropylene, polyester, etc., uniaxially or biaxially stretched film alone or at least one of these The composite film was used.

As the packaging method, a general method for food packaging is used. For example, inert gas sealed packaging, skin pack packaging, deep drawing vacuum packaging, in-line system adhesive packaging, offline system adhesive packaging, vacuum packaging, vacuum shrink packaging, etc. may be mentioned. When a shrinkable film is used, it may be heat-treated to shrink the film. The heat treatment can be performed using a hot water tank, hot water shower, jet steam, or the like.

The present invention is characterized in that food is treated with an organic acid and then treated with ultraviolet rays. By such a specific order of treatment, the sterilizing action of ultraviolet rays is synergized with the sterilizing action of the organic acid to obtain an excellent sterilizing effect. On the other hand, no synergistic effect is observed when the food is treated with ultraviolet rays and then treated with the organic acid.

The ultraviolet rays can be obtained by a commercially available ultraviolet sterilizer, and ultraviolet rays in the UV-C (100 to 280 nm) category are preferably used. And the dose of ultraviolet rays (illuminance x time) is 5 to 120 per unit surface area of food surface.
0 mW · sec / cm ² , preferably 8-800 mW ·
The range is sec / cm ² . UV dose is 5mW
If it is less than sec / cm ² , the bactericidal effect is not sufficient and 120
If it is 0 mW · sec / cm ² or more, a remarkable increase in bactericidal effect cannot be expected.

In particular, the method of wrapping a food treated with an organic acid in a film and then treating it with ultraviolet rays has the effect of preventing the influence of bacterial contamination before the ultraviolet ray treatment while maintaining the effects of the organic acids and ultraviolet rays. is there.

[0014]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

Example 1 E. coli (IAM12) was added to a lactic acid aqueous solution having a concentration of 0 to 100 mM.
53) was added to obtain a suspension containing 1.5 × 10 ⁴ cells / ml. A sliced Bonless ham having a surface area of 10 cm × 10 cm was inoculated with 0.3 ml of the above suspension, and a polyvinylidene chloride multi-layer film was used.
It was vacuum-packed with a 00 type vacuum packaging machine under the conditions of dial 4 for 40 seconds.

The structure of the polyvinylidene chloride multilayer film is such that the outermost layer is linear ultra-low density polyethylene, the outer layer is ethylene / methacrylic acid copolymer, the core layer is polyvinylidene chloride, and the inner layer is ethylene / methyl acrylate copolymer. The innermost layer is a linear ultra-low density polyethylene, the adhesive layer is an ethylene / vinyl acetate copolymer (composition mass ratio 85:15), the total thickness is 55 μm, and the ultraviolet ray (253.7 nm) transmittance is 80. %Met.

Transmission dose 0 to 800 mW · sec / cm ²
Of the above-mentioned packaged samples were treated with different ultraviolet rays (253.7 nm) of E. coli, and the number of E. coli was measured for each treated sample. For the measurement of the number of E. coli, a gauze containing 1 ml of sterile physiological saline was used, and the treated surface area was 10 cm × 10.
Wipe away E. coli from sliced Bonresham, which is cm.
Next, this gauze was washed out with 9 ml of sterile physiological saline, and the method was carried out by a method of measuring the number of Escherichia coli in these solutions by a conventional method. The results are shown in Table 1.

[0018]

[Table 1]

From the above results, it is possible to obtain 8 when the ultraviolet ray is alone treated.
It was found that it is effective at a transmitted dose of ˜800 mW · sec / cm ² , and is effective at a concentration of 10 to 100 mM when treated with lactic acid alone. Further, the combined use of the lactic acid treatment and the ultraviolet treatment showed the effect at a lower transmitted dose than the case of the ultraviolet treatment alone. Also, the bactericidal effect was significantly enhanced.

That is, in the case of a single treatment with ultraviolet rays, 8 mW
-At a permeation dose of sec / cm ² , the effect of changing the number of digits of E. coli was not recognized, and 96 mW · sec / c
It was confirmed that increasing the permeation dose up to m ² reduced the number of digits of E. coli by one digit. In the case of treatment with lactic acid alone, at the concentration of 10 mM, the effect of changing the number of digits of E. coli was not recognized.

On the other hand, when the lactic acid having a concentration of 10 mM is treated and then the ultraviolet rays having a transmission dose of 8 mW · sec / cm ² are used, the effect of reducing the number of digits of E. coli by one digit is recognized. When treated with ultraviolet light having a transmitted dose of 320 mW · sec / cm ² after treatment with lactic acid
The effect of lowering the number of digits of E. coli by two digits was recognized. In each case, no offensive odor was observed and the taste was unchanged.

Example 2 In Example 1, acetic acid and the number of bacteria were 1.1 × 10 ⁴ / m 2.
The bactericidal effect against Escherichia coli was examined by the same method as in Example 1 except that the suspension of 1 was used. Table 2 shows the results.

[0023]

[Table 2]

From the above results, it is possible to obtain 8 by the treatment with ultraviolet rays alone.
It was found that it is effective at a transmitted dose of ˜800 mW · sec / cm ² and is effective at a concentration of 6 to 100 mM when treated with acetic acid alone. Furthermore, by using the acetic acid treatment and the ultraviolet treatment together, the effect was observed at a lower transmitted dose than in the case of the ultraviolet treatment alone. Also, the bactericidal effect was significantly enhanced.

That is, in the case of a single treatment with ultraviolet rays, 8 mW
・ At a permeation dose of sec / cm ² , the effect of changing the number of digits of Escherichia coli was not recognized, and 40 mW · sec / c
It was confirmed that increasing the dose up to m ² reduced the number of digits of E. coli by one digit. Further, in the case of treatment with acetic acid alone, at the concentration of 6 mM, the effect of changing the number of digits of the number of E. coli was not recognized.

On the other hand, it was treated with acetic acid having a concentration of 6 mM.
Later transmission dose 8 mW · sec / cm ²Treated with UV light
If the number of E. coli bacteria is reduced by one digit, the effect is confirmed.
And a transmission dose of 96 after treatment with acetic acid at a concentration of 6 mM.
mW · sec / cm²E. coli when treated with
The effect of lowering the number of digits of the bacterium by 2 digits was recognized. Well
In each case, no offensive odor was observed and the taste was the same.
There wasn't.

Example 3 In Example 1, chilled beef was used, and the transmitted dose was 0 to
Using 640 mW · sec / cm ² ultraviolet light,
The bactericidal effect on Escherichia coli was examined by the same method as in Example 1 except that a lactic acid aqueous solution having a concentration of 0 to 10 mM was used. The results are shown in Table 3.

From the above results, it was found that 8
It was found to be effective at a transmitted dose of ˜640 mW · sec / cm ² . It was found that the treatment with lactic acid alone was effective at a concentration of 10 mM. Further, the combined use of the lactic acid treatment and the ultraviolet treatment showed the effect at a lower transmitted dose than the case of the ultraviolet treatment alone. Also, the bactericidal effect was significantly enhanced.

That is, in the case of the ultraviolet ray alone treatment, 8 mW
・ At a transmitted dose of sec / cm ² , the effect of changing the number of digits of E. coli was not recognized, and 80 mW · sec / c
By increasing the transmitted dose up to m ^2, the effect of reducing the number of colonic bacteria by one digit was recognized. In the case of treatment with lactic acid alone, at the concentration of 10 mM, the effect of changing the number of digits of E. coli was not recognized.

On the other hand, when the lactic acid having a concentration of 10 mM is treated and then the ultraviolet rays having a transmission dose of 8 mW · sec / cm ² are used, the effect of reducing the number of digits of Escherichia coli by one digit is recognized. When treated with ultraviolet light having a transmitted dose of 80 mW · sec / cm ² after the treatment with lactic acid of No. ² , the effect of lowering the number of digits of Escherichia coli by two digits was recognized.
In each case, no offensive odor was observed and the taste was unchanged.

[0031]

[Table 3]

Comparative Example 1 Escherichia coli (IAM1253) was added to physiological saline to obtain a suspension having a bacterium number of 9.3 × 10 ³ / ml. Surface area 10 cm
X 10 cm chilled beef was inoculated with 0.3 ml of the suspension, and the dose was 0 to 400 mW · sec / cm ² of ultraviolet rays.
(253.7 nm). Then, concentration 0-10
0.3 ml of a mM lactic acid aqueous solution was applied, and the number of E. coli was measured for each treated sample in the same manner as in Example 1. The results are shown in Table 4.

From the above results, in the case of treatment with ultraviolet rays alone,
At a dose of 400 mW · sec / cm ² , the effect of lowering the number of digits of Escherichia coli by one digit was recognized. In the case of treatment with lactic acid alone, at the concentration of 10 mM, the effect of changing the number of digits of E. coli was not recognized.

On the other hand, when it was treated with ultraviolet rays having a dose of 400 mW · sec / cm ² and then with lactic acid having a concentration of 10 mM, the effect of lowering the digit number of Escherichia coli by one digit was recognized. The effect is a dose of 400 mW · sec / cm ²
It was the same as the case of the single treatment with ultraviolet rays. That is, the synergistic effect of the ultraviolet treatment and the lactic acid treatment was not recognized.

[0035]

[Table 4]

On the other hand, a chilled beef having a surface area of 10 cm × 10 cm was inoculated with the suspension used in Comparative Example 1, and then 0.3 ml of a 10 mM lactic acid aqueous solution was applied.
Ultraviolet rays with a dose of 400 mW · sec / cm ² (253.7
nm). The number of E. coli cells was measured in the same manner as in Example 1. With this treatment method, the number of Escherichia coli was 3.4 × 10 ¹ , and it was confirmed that the number of digits of E. coli was reduced by two digits. That is, a synergistic effect of lactic acid treatment and ultraviolet treatment was recognized.

[0037]

According to the present invention described above, the synergistic action of the organic acid treatment and the ultraviolet treatment provides a high bactericidal effect at a value lower than the organic acid concentration of the single treatment or the ultraviolet irradiation dose of the single treatment. To be Therefore, according to the present invention, there is provided an improved food sterilization method that does not adversely affect the taste and does not cause a problem such as an offensive odor.

Claims (7)

[Claims] 1. A method of sterilizing a food, which comprises treating the food with an organic acid and then treating it with ultraviolet rays. 2. A method for sterilizing a food, which comprises treating the food with an organic acid, packaging it with a film, and then treating it with ultraviolet rays. 3. The organic acid is acetic acid, fumaric acid, citric acid,
The method for sterilizing food according to claim 1 or 2, which is one or more selected from the group consisting of succinic acid, malic acid, lactic acid, tartaric acid and gluconic acid. 4. The sterilization method for food according to claim 1, wherein acetic acid is used as the organic acid. 5. The method for sterilizing food according to claim 1, wherein lactic acid is used as the organic acid. 6. The method for sterilizing food according to claim 1, wherein the concentration of the organic acid is 2 to 70 mM. 7. The dose of ultraviolet rays per unit area of the food surface is 5 to 1200 mW · sec / cm ^2.
7. The method for sterilizing food according to any one of 6 to 6.