JP2002369672A - Method for sterilizing food by using lactic fermentation liquor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for sterilizing a food by using a lactic fermentation liquor, which makes it possible that effectiveness of the lactic fermentation liquor as a bacteriocin which is lost in a short time in the presence calcium ions and/or magnesium ions is retained for a long time. SOLUTION: This method for sterilizing the food comprises adding a water- soluble calcium or magnesium salt and the lactic fermentation liquor containing the bacteriocin to the food. The calcium or magnesium salt and the lactic fermentation liquor may be added at the same time, the lactic fermentation liquor may be added later than the addition of the calcium or magnesium salt by a time difference of 10 min to 4 hr, or the calcium or magnesium salt may be added later than the addition of the lactic fermentation liquor by a time difference of 10 min to 4 hr.

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 with a lactic acid fermentation solution, which maintains the effect of bacteriocin in a lactic acid fermentation solution, which is lost in a short time, in the presence of calcium ions and / or magnesium ions for a long time. About.

[0002]

2. Description of the Related Art Sterilization methods for heating food under normal pressure are widely used. However, the spores formed by the spores remain without being sterilized, and germinate and proliferate when the environment improves. In general, spores are widely present in the natural environment, and are also abundant in food materials such as grains and beans. In rare cases, it has been reported that bacteria such as Clostridium botulinum (botulinum) and Bacillus cellius (cellus) grow and cause food poisoning. The problem of spores is one of the worst producers in producing tasty and good food. Techniques are being pursued to maintain the bacterial flora normally by suppressing the number of spores as much as possible, even if the spores cannot be eliminated, and to produce a slightly tasty food that is not contaminated by the spores. The sterilization process is generally performed at a temperature of 100 ° C. or lower, and the heat sterilization under pressure exceeding 100 ° C. generates a so-called retort odor and deteriorates the flavor inherent in food, such as taste, texture and color. Therefore, it cannot be adopted in a general food manufacturing process in many cases.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to foods for which high-temperature and high-pressure treatment is not preferred, under mild conditions without using high-temperature and high-pressure sterilization, and without relying on chemical synthetic germicides. He has been studying the technology to suppress the growth of and increase the shelf life of food. On the other hand, the active ingredient of the lactic acid fermentation broth is nisin belonging to bacteriocin. It is known that the activity of nisin is significantly reduced in the presence of a cation having a valency of II or III, such as a magnesium ion or a calcium ion (Koshobo, Biopreservation, pp. 69-70). The present inventors conducted tests to confirm this known fact, and surprisingly found that coexistence of calcium ions and lactic acid fermentation solution significantly improved the efficacy of lactic acid fermentation solution. By using calcium ions and magnesium ions together, a method of using a lactic acid fermentation broth more efficiently has been invented.

[0004]

The constitution of the present invention is to add water-soluble calcium or water-soluble magnesium and a lactic acid fermentation solution containing bacteriocin to a food. The lactic acid fermentation solution may be added with a time delay with a delay, or the water-soluble calcium or magnesium may be added with a time delay with a delay.

[0005] Bacteriocin is generally fast-acting and has a bactericidal effect, but its efficacy is liable to decrease and tends to decrease during long-term contact with food, allowing the growth of various bacteria thereafter. is there. Calcium, on the other hand, has no immediate effect but tends to maintain its efficacy, and the intended purpose could be achieved by using both together. That is, when a bacteriostatic agent and bacteria were added to the medium and cultured at 35 ° C. for 18 hours, the number of bacteria was reduced by one order in the case of bacteriocin alone and 3 in the case of calcium ion alone as compared with the blank. The order had dropped. On the other hand, when bacteriocin and calcium ion were added simultaneously, the order decreased by 5 orders, when bacteriocin was added 3 hours after the addition of bacteria and calcium ion, it decreased by 6 orders. Was added, a decrease of as much as 7 orders was observed.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The lactic acid fermentation liquor used in the present invention is:
Lactic acid bacteria producing bacteriocin (Lactococcus lacti
s) is obtained by fermentation propagation, and bacteriocin is contained in the culture solution. Such lactic acid bacteria include:
Lactococcus lactis subsp. La that produces nisin A
In addition to ctis, Lactococcus lactis subsp. cremoris,
Lactococcus lactis subsp. Chacetilactis and the like. For example, Lactococ producing nisin Z
cus lactis IO-1 (JCM 7638) can be seeded by culturing it in a TGC medium, and can be used as a seed bacterium as needed by storing it in a refrigerator. As a medium,
Whey, starch saccharified liquid, glucose for food, etc. can be used as a carbon source, and decomposition products of whey protein concentrate, corn peptide, soy peptide, commercial seasoning liquid raw material, shochu lees, yeast extract for food can be used as a nitrogen source. Etc. can be used. From the obtained lactic acid fermentation broth, only the medium supernatant is recovered by centrifugation, and the titer is expressed in U / g based on a standard product (Nisin, ICN Biomedical). In some cases, the lactic acid fermentation solution may be dried and used in a dry state.

When the lactic acid fermentation solution has a high titer, or when a thin solution can be used depending on the application, it can be used as it is, but preferably it is concentrated. Although various methods for concentrating nisin Z have been proposed, a membrane concentrating method using a charged reverse osmosis membrane made of polysulfone is industrially advantageous.
Concentrate it more than twice and use it at about 10,000 U / g. Further, the lactic acid fermentation broth can be roughly purified and used. Although various purification methods have been proposed, a method using a cation exchanger is an industrially preferable method. Various cation exchangers are also on the market, but select one that completely absorbs and elutes bacteriocin.

The present inventors have found that divalent cations, particularly calcium ions and magnesium ions, are effective as substances used in combination with bacteriocin. It is effective to add both to the food at the same time, but it is more effective to add one of them with a time delay. The time difference is 10 minutes to 4 hours, and 20 minutes to 3 hours, more preferably 30 minutes to 2 hours in consideration of the convenience and effect in operation. Also, adding bacteriocin first and adding a divalent cation later provides more excellent effects than adding a divalent cation first.

[0009] The amount of calcium to be added is 0.1% as Ca.
It is from 0.01 to 2%, preferably from 0.05 to 1%. If it exceeds 2%, the flavor of the food is adversely affected, and if it is less than 0.01%, a sufficient effect cannot be expected. Generally, a water-soluble calcium salt is used, and calcium chloride is preferably used. Also, commercially available calcined calcium, particularly shell calcined calcium, is preferably used. In addition, water-soluble magnesium salts can also be used. Although the food using the present invention is not particularly limited, a particularly remarkable effect can be expected if it is used for a food that can be sterilized by boiling but cannot be sterilized up to spores.

[0010]

EXAMPLES Example 1 (1) Preparation of lactic acid fermentation broth Lactococcus lactis IO-1 (JCM 7638) was inoculated on a standard agar medium. The culture was performed under aerobic conditions or a facultative anaerobic condition by supplying 25% or less of oxygen that had been filtered and sterilized. The rotation speed was 250 rpm, and the culture temperature was about 3.
The cells were cultured at 0 ° C. for 15 hours. The resulting culture was Nisin Z
It had an activity of about 3500 U / g. The supernatant of the obtained culture is subjected to 20 to 4 at 7000 to 10000 rpm.
Centrifuge for 0 minutes, collect only the supernatant, and concentrate with concentrated hydrochloric acid.
Adjusted to 3.0 ± 0.5, left at 4 ° C. for 24 hours,
The mixture was centrifuged at 000 to 10000 rpm for 20 to 40 minutes, and concentrated using a polysulfone ultrafiltration membrane by a 100% nitrogen gas pressurization method. As a result, the lactic acid fermentation liquid was concentrated 3 to 5 times, and a concentrated liquid of about 10,000 U / g was obtained.

(2) Preparation of Bacillus subtilis solution Bacillus subtilis C1 was prepared by using TS medium at 35 ° C.
The cells were cultured with shaking at 140 rpm for 8 hours. TS medium is 1
The following components are contained in a liter. Casein digest 17.0 g Papain digest of soybean 3.0 g Dextrin 2.5 g Salt 5.0 g Dipotassium phosphate 2.5 g

(3) Antibacterial test method An antibacterial test was performed using a microtiter plate and a TS medium. For each well, the lactic acid fermentation solution was 200 U / ml as Nisin Z, and the calcium concentration was Ca
Cl ₂ was added so as to be 5%. The inoculum volume of the bacterial solution prepared in (2) was set to 10 μl, and the total volume of each well was 200 μl.
The culture was carried out at 35 ° C. for 18 hours.
For bacterial testing, take 100 μl of culture solution from each well,
The mixture was diluted with sterile physiological saline, poured and layered on a standard agar medium, cultured at 35 ° C. for 18 hours, and the number of bacteria was counted.

The number of bacteria when only bacteria are added is 1.20E
+08, the number of bacteria when the lactic acid fermentation solution was added was 7.80.
The number of bacteria when only E + 07 and calcium ions were added was 7.40E + 05, and the number of bacteria when lactic acid fermentation broth and calcium ions were simultaneously added was 2.5E + 04.
Here, when calcium ions and a lactic acid fermentation solution were used in combination, the effect of adding either one with a time difference was measured. 0 minutes, 20 minutes, 40 minutes, 60
After 120 minutes, 120 minutes and 180 minutes, the measurement was performed for the case where the lactic acid fermentation solution was pre-added and the case where calcium ion was pre-added. In each case, after adding both the lactic acid fermentation broth and calcium ions, the number of bacteria after culturing at 35 ° C. for 18 hours was measured, and the results are shown in Table 1. From Table 1, it was found that the method of adding the calcium ions with a delay is more effective than the method of adding the lactic acid fermentation solution with a delay. Even if the addition of calcium ions was delayed for 20 minutes, the number of bacteria could be reduced by two orders of magnitude.

[0014]

[Table 1]

Example 2 A fixed amount of commercially available soymilk was added to a 200 ml Erlenmeyer flask.
1 ml of the bacterial solution and a required sample were added, and if necessary, distilled water was added to make a total volume of 100 ml. Lactic acid fermentation solution is Nisin Z
The CaCl ₂ solution was added so as to be 5% so as to be 200 U / ml. After adding the bacterial solution and the lactic acid fermentation solution to the soymilk, 1 hour later, a CaCl ₂ solution was added to a concentration of 5% to make the total volume 100 ml. The number of bacteria was measured at regular time intervals. At the same time, the number of bacteria was measured for a sample to which only a lactic acid fermentation solution was added, a sample to which only a CaCl ₂ solution was added, and a blank (a sample to which neither a lactic acid fermentation solution nor a CaCl ₂ solution was added). The number of bacteria was measured at 0.
Sample 1 ml at a time, and add 10
And cultured on a standard agar medium at 35 ° C. for 24 hours, and the number of bacteria was confirmed.

[0016]

[Table 2]

Example 3 A bacterial solution and a CaCl ₂ solution were added to soymilk and cultured for 1 hour.
The test was carried out in the same manner as in Example 2 except that the lactic acid fermentation solution was added, and the results are shown in Table 3. At the same time, the number of bacteria was measured for a sample to which only the lactic acid fermentation solution was added, a sample to which only the CaCl ₂ solution was added, and a blank (a sample to which neither the lactic acid fermentation solution nor the CaCl ₂ solution was added).

[0018]

[Table 3]

From the above examples, the lactic acid fermentation liquor has a quick effect, but loses its effect in a short time. However, by using a calcium ion together with a time difference, the effectiveness of the lactic acid fermentation broth was successfully maintained for a long time. In particular,
A significant effect can be obtained by adding calcium ions 30 minutes to 1 hour after the addition of the lactic acid fermentation broth.

[0020]

According to the present invention, it is possible to maintain the lactic acid fermentation broth as a bacteriocin for a long period of time, and the food can be stored for a long period of time simply by adding and mixing. This fermentation is particularly useful for spores that cannot be sterilized by boiling.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Kenjiro Ogura 5-27-5 Matsushima, Higashi-ku, Fukuoka City Fukuoka Prefecture (72) Sayaka Soma Inventor 5-27-5 Matsushima, Higashi-ku Fukuoka City, Fukuoka Prefecture (72) Inventor Harumi Nomiyama 5-27-5 Matsushima, Higashi-ku, Fukuoka City, Fukuoka Prefecture Incorporated Company (72) Inventor Yasuhide Tanimoto 1-38-1 Shin-Katsutachi-cho, Omuta City, Fukuoka Prefecture (72) Inventor Kenji Sonomoto 6-10-1 Hakozaki, Higashi-ku, Fukuoka City F-term in Kyushu University (reference) 4B021 MC01 MK02 MK06 MK08 MK23 MP01

Claims (5)

[Claims] 1. A method for sterilizing foods with a lactic acid fermentation solution, comprising adding water-soluble calcium or water-soluble magnesium and a lactic acid fermentation solution. 2. A method for sterilizing foods with a lactic acid fermentation solution, comprising adding water-soluble calcium or water-soluble magnesium with a time lag after adding the lactic acid fermentation solution. 3. A method for sterilizing foods with a lactic acid fermentation solution, comprising adding a water-soluble calcium or water-soluble magnesium and then adding a lactic acid fermentation solution with a time lag. 4. A method for sterilizing food by a lactic acid fermentation solution, comprising simultaneously adding a lactic acid fermentation solution and water-soluble calcium or water-soluble magnesium. 5. The method for sterilizing food with a lactic acid fermentation solution according to claim 1, wherein the lactic acid fermentation solution contains bacteriocin.