JP2006191865A - Bacteriostatic method for processing equipment and method for producing sterilized fluid substance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bacteriostatic method for processing equipment effectively controlling increase of thermophile bacteria or the like when fluid substance such as food is kept in a high-temperature area in processing equipment without affecting flavor so as to result in preventing alteration of physicality such as viscosity of the fluid substance. <P>SOLUTION: The bacteriostatic method for processing equipment comprises treating the fluid substance containing lysozyme having concentration enough to control increase of the thermophile bacteria in the processing equipment so as to control the increase of the thermophile bacteria in the processing equipment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a bacteriostatic method for processing equipment such as fluid food, beverages and pharmaceuticals, and a method for producing the fluid substance.

In general, when producing retort food such as soup and stew, first, the food is cooked in a cooking kettle, and the cooked food is sent from the cooking kettle to a filling machine through a pipe with a pressure pump or the like. Then, the container is filled and sealed, and the sealed food in the container is subjected to retort heat sterilization treatment. Separately, in the aseptic filling technique (aseptic treatment), cooked food is sent from a cooking kettle to a sterilizer through a pipe with a pressure feed pump and subjected to heat sterilization treatment. After cooling, the container is filled and sealed in a sterile state.
In the manufacturing technique as described above, food is normally cooked at a temperature of about 100 ° C., and after the processing, the food is sent from the cooking pot through a pipe to a filling machine or a heat sterilizer. During such processing, in a specific part of the processing equipment, the food may be kept at a product temperature of about 50 ° C. to 80 ° C. (hereinafter, the temperature range is referred to as a high temperature range). That is, the food is kept in the cooking pot, or the flow of the food is stopped and stays at a pipe connection part, a valve, a pump or the like in the processing equipment.

As mentioned above, there are no reports that have been studied in detail about bacteriological and quality problems when food is kept in high temperature areas in processing facilities.
As for the above-mentioned point, the present inventor has made a detailed study. When food or the like is kept in a high temperature region for 4 hours or more in a processing facility, a thermophilic bacterium (mainly Bacillus stea) is used.
It has been found that growth of R. thermophilus, Bacillus coagulans, etc. can be problematic.
Furthermore, if the food contains starch (eg, white sauce), as described above, when thermophilic bacteria grow in the food during processing, the grown thermophilic bacteria decompose using starch as a nutrient source. , Food viscosity tends to decrease. In addition, thermophilic bacteria tend to produce organic acids and lower the pH of food. Due to the above, it has been found that the growth of thermophilic bacteria during processing has a problem of significantly reducing the quality of food.
On the other hand, various germicides for processing equipment are known. For example, lysozyme, which is a natural enzyme, is known as an enzyme having a lytic action. In Non-Patent Document 1, lysozyme is an enzyme that acts to cleave the β-1,4-glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine in the peptidoglycan layer of the bacterial cell wall, thereby It is described to lyse bacterial cells. Moreover, although the above effect is reported in many gram-positive bacteria in Reference 1, the surface of gram-negative bacteria is covered with a lipoprotein-lipopolysaccharide layer, which prevents contact with lysozyme. It is described that it does not lead to lysis.
Patent Document 2 describes that lysozyme generally has a narrow antibacterial spectrum, and therefore, when added as a shelf life improver to foods, it is mixed with other antibacterial agents and used as a composite preparation. . Furthermore, Non-Patent Document 3 includes disinfection of hands as an alcohol preparation, machinery,
It is described that it is used for sterilization of kitchen knives, cutting boards, work tables and the like.
Furthermore, sucrose fatty acid esters are widely used in beverages such as coffee as a means of suppressing the growth of thermophilic bacteria. However, sucrose fatty acid esters have a high effective concentration because of many inhibiting factors such as starch in processed foods, and a unique bitter taste can be felt.
Toshio Matsuda, “Chemistry of Food Microbial Control”, Kobo Shobo Publishing, 1998.2.25 first edition, P270 JP-A-6-225740 Osumi Yukio, Clinical Nutrition, Vol.74, No.4, 1989.4, P345-P347

The present invention effectively suppresses the growth of thermophilic bacteria and the like in a processing facility when a fluid substance such as food is retained in a high temperature range without affecting the flavor, and the viscosity of the fluid substance based on this It is an object of the present invention to provide a bacteriostatic method for processing equipment that can prevent deterioration in taste quality such as physical properties and pH.
Furthermore, in the processing equipment, when the fluid substance is retained in a high temperature range, the growth of thermophilic bacteria is effectively suppressed, and the physical properties such as the viscosity of the fluid substance and the taste quality such as pH are prevented from deteriorating based on this. Then, it aims at providing the manufacturing method of a fluid substance which can obtain a high quality fluid substance.

The present inventor has focused on lysozyme in order to effectively suppress the growth of thermophilic bacteria and the like in the fluid substance in the processing facility, and as a result of conducting detailed experimental verification of its effectiveness, the fluid state containing lysozyme. It has been found that the growth of thermophilic bacteria can be effectively suppressed at a low concentration by treating the substance with a processing facility.
The present invention has been completed on the basis of the above knowledge, and by treating a fluid substance containing lysozyme at a concentration sufficient to suppress the growth of thermophilic bacteria in the processing equipment, It is characterized by a bacteriostatic method for processing equipment characterized by suppressing proliferation.
The present invention suppresses the growth of thermophilic bacteria in the processing facility by treating a fluid substance containing lysozyme at a concentration sufficient to suppress the growth of thermophilic bacteria in the processing facility, and during the treatment, Another method is a method for producing a sterilized fluid substance, which comprises subjecting the fluid substance to heat sterilization.

With the above-described configuration of the present invention, in a processing facility, when a fluid substance such as food is kept in a high temperature range, the proliferation of thermophilic bacteria and the like is effectively suppressed without affecting the flavor, and the fluid substance based on this It is possible to obtain a high-quality fluid substance by preventing the physical properties such as viscosity and the quality of taste such as pH from being altered.

Hereinafter, the present invention will be described in detail.
In the present invention, the “fluid substance” is a substance having fluidity that is eaten by a person such as a food, beverage or pharmaceutical. The target substances include all substances that may cause the growth of thermophilic bacteria when kept in a high temperature range. For example, thermophilic bacteria are likely to grow with substances having a pH of 5.0 or higher, and the present invention is effective against them. Examples of the types of target substances include foods such as curry, stew, cream stew, gratin, soups, pasta sauce, cooking sauces, beverages such as coffee, milk drinks, soft drinks, so-called drinks, pasty chemicals And the like.
In addition, for fluid substances containing starch and / or changes in pH that tend to affect quality,
The present invention is particularly effective. In other words, the inherent quality of the substance is maintained by effectively avoiding the lowering of the viscosity of food based on the decomposition of starchy substances as a nutrient source, and the decrease in pH due to organic acids produced by the thermophilic bacteria. This is because an effect that can be achieved is obtained. Examples of fluid substances that contain starch and are susceptible to changes in pH are foods such as curry, stew, cream stew, gratin, soups, pasta sauce, risotto sauce, beverages such as coffee and milk drinks, and pharmaceuticals Etc.

“Lysozyme” refers to an enzyme that hydrolyzes between β-1,4 bonds between N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) present in mucopeptides of bacterial cell walls. Regardless of reaction mechanism, it is a substrate
Anything that shows lytic activity against Micrococus luteus or other gram-positive bacteria is included. Generally, chicken type lysozyme (C type), goose type lysozyme (
G type), phage type lysozyme, plant lysozyme, bacterial lysozyme and the like.
As lysozyme, lysozyme derived from egg white, fish body surface mucus, microbial origin, bacteriophage-derived lysozyme and lysozyme prepared using genetic manipulation techniques, and these lysozymes are acid, alkali, heated, Examples thereof include improved lysozyme chemically and physically treated by pressurization.
In the case where the fluid substance is a food, beverage, medicine or the like, any substance that is permitted to be used for each may be used. Examples of commercially available lysozyme include egg white lysozyme and quail egg lysozyme. Since an effective concentration for achieving bacteriostatic can be easily set, lysozyme (including so-called preparations) purified by the various methods described above can be suitably used. Although lysozyme derived from the raw material of the fluid substance can also be used, in this case, in order to set an effective concentration for achieving bacteriostasis, the raw material is subjected to prior experimental verification. It is necessary to determine the formulation.

“Processing equipment” refers to equipment that has a situation in which fluid substances are retained in a high temperature range in the equipment. For example, there is a facility in which a cooking pot for fluid substances, a pressure pump for feeding cooked substances from the cooking kettle to a filling machine, and a filling machine for filling and sealing substances in a container are connected via a pipe. This includes the addition of a retort heat sterilizer for subjecting the food in a sealed container to a retort heat sterilization treatment. Moreover, the aseptic filling equipment which connected the cooking pot, the pressure feed pump, the sterilizer, the cooler, the filling machine, etc. via piping is mentioned. Of course, when a single facility, for example, a fluid substance is kept in a cooking kettle after cooking, the cooking kettle alone is also included. The equipment
What equipped various parts, such as a measuring instrument, a valve, and various tanks, may be used. It may be a chemical plant for producing pharmaceuticals and the like.

The target bacteria to be bacteriostatic in the present invention are all thermophilic bacteria that can grow in a high temperature range, for example,
Bacillus stearothermophilus, Bacillus coa
gulans and the like. For example, it is a high-temperature bacterium that becomes a problem when mixed in foods, and can grow at a growth temperature range of 40 to 70 ° C., an optimum temperature of 50 to 60 ° C., and a pH of 5.0 or more. The present invention is not limited to the above microorganisms as long as the growth can be suppressed with lysozyme.
The term “bacteriostatic” refers to inhibiting the growth of thermophilic bacteria in processing equipment to 10 times or less. If the number of bacteria is suppressed to about 1.0 × 10 ^{5 to} 1.0 × 10 ⁶ cells / g or less, preferably about 1.0 × 10 ^{4 to} 1.0 × 10 ⁵ cells / g or less, In the case of a fluid substance that can be maintained in a favorable state from the standpoint of quality, and at the same time contains starchy substances and / or changes in pH are liable to affect quality, it is possible to prevent physical properties such as viscosity and taste quality such as pH from being altered. it can.
When the growth of thermophilic bacteria exceeds about 1.0 × 10 ^{5 to} 1.0 × 10 ⁶ cells / g, the viscosity of the fluid substance tends to decrease and the pH tends to decrease. It is important in terms of product quality to suppress within the range. Furthermore, in consideration of practical operating conditions and product quality of processing equipment such as food, beverages, and pharmaceuticals, it is desirable that the above bacteriostasis is achieved for 8 hours or more, preferably 12 hours or more. . As a result, the processing equipment can be operated for a long time, and high-quality products can be manufactured in large quantities at low cost without maintenance of the equipment. In addition, when processing foodstuffs, such as a white sauce, with the processing equipment etc. which are shown in FIG. 1 mentioned below, bacteriostasis can usually be achieved only for about 4 hours.

In order to achieve the above bacteriostasis, the concentration of lysozyme contained in the fluid substance is 50 ppm or more, preferably 100 to 1000 ppm. If the concentration is below the above range, the target bacteriostatic may not be achieved. If the concentration exceeds the above range, the cost increases. However, the concentration is not limited to the above.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing an embodiment of a retort food sterilizing apparatus to which the present invention is applied. The retort food sterilizer A includes a cooking kettle 1 such as a roasting kettle with stirring blades for cooking the fluid food B (fluid substance) at about 100 ° C., and the cooked food B A pressure feed pump 2 such as a rotary pump for feeding to the filling machine 3 and a filling machine 3 for filling and sealing the food B in the container C are connected via a pipe 4. A pipe 4 extending from the cooking pot 1 to the filling machine 3 has vertical and horizontal pipe connecting portions 7. The sterilizer A further includes a retort heat sterilizer 5 for subjecting the sealed food in a container to a retort heat sterilization process.

In the present invention, in order to achieve bacteriostasis by suppressing the growth of thermophilic bacteria in the sterilizer A, the fluidized food B contains lysozyme at a concentration sufficient to bacterize the thermophilic bacteria. That is, the fluid food B to which lysozyme is added is cooked in the cooking pot 1, and is sent from the cooking pot 1 to the filling machine 3 by the pressure pump 2, and the food B is filled and sealed in the container C by the filling machine 3. The sealed food in the container is subjected to retort heat sterilization treatment by the retort heat sterilizer 5.

As described above, the sterilizer A is operated, and for example, the food B is continuously sent from the cooking pot 1 to the filling machine 3 and the retort heat sterilizer 5 for 8 hours or more to produce the retort food in a container. In this case, the food B flowing to the sterilizer A contains lysozyme at a concentration sufficient to bacterize the thermophilic bacteria, so that the food B
Even if the flow of water stops and stays, it is possible to reliably suppress the growth of thermophilic bacteria in the staying portion. Accordingly, even if the food B contains starch, the viscosity of the food does not decrease due to decomposition of the starch by thermophilic bacteria.
Can also be prevented. The above action is achieved continuously after adding lysozyme to food B, until the lysozyme is deactivated by subjecting the food in a container to retort heat sterilization, and continues throughout the operation of apparatus A. Achieved. From this, it becomes possible to manufacture an extremely high-quality containerized retort food with high production efficiency.

EXAMPLES Next, although an Example demonstrates this invention in more detail, this invention is not limited to an Example.

Example 1
(Relation between lysozyme content and growth of thermophilic bacteria)
B. coagulans (NBRC12583), B.I. stearothermophilus
(ATCC12980) was streaked on a normal agar medium and cultured at 55 ° C. for 3 days. Furthermore, in order to refresh the bacteria, it was newly streaked on a normal agar medium and cultured for 24 hours. Thereafter, the bacterial solution is adjusted with a phosphate buffer solution, inoculated so as to be about 10 ³ cells / g, and egg white lysozyme is added to each 0
White sauce containing ppm (no additive), 50ppm, 100ppm, 200ppm (p
H6.0 and a viscosity of 700 mPa · s) were sealed in a pouch at a rate of 30 g, and cultured at 55 ° C. in a stationary state in a thermostatic bath. 10g after 4, 8, 10, 12, 16 hours for each
And the number of bacteria was measured. Table 1 and FIGS. 2 and 3 show the number of thermophilic bacteria and their changes after each predetermined time.

As shown in Table 1 and FIG. 2 and FIG. 3, the white sauce containing egg white lysozyme has the growth of thermophilic bacteria suppressed to 10 times or less after 4 to 16 hours regardless of the concentration of lysozyme. A bacteriostatic effect was clearly observed. On the other hand, white sauce not containing egg white lysozyme, thermophilic bacterium grown to 5.1 × 10 ⁶ cells /G,5.2×10 ⁶ cells / g after 4 hours have passed, 8
After the elapse of time, thermophilic bacteria grew to 3.5 × 10 ⁸ cells / g and 1.7 × 10 ⁷ cells / g. In addition, in FIG. coagula
No proliferation of ns was observed.

(Relationship between growth of thermophilic bacteria and product quality)
White sauce has a tendency to decrease in viscosity and pH and change in physical properties and taste when the number of thermophilic bacteria exceeds about 1.0 × 10 ^{5 to} 1.0 × 10 ⁶ cells / g. . In this respect, the viscosity and pH of the product containing egg white lysozyme were not recognized at all, and the original thickness and flavor of the white sauce were achieved.
On the other hand, the white sauce containing no egg white lysozyme was remarkably reduced in viscosity and pH, changed in physical properties and felt sour in taste. That is, B.I. coagula
It became pH4.9 with the white sauce 8 hours after inoculating ns, and the viscosity could not be measured. B. The same results were obtained with the white sauce after 8 hours after inoculation of stearothermophilus, and the viscosity of the white sauce dropped and the acidity was felt.

Example 2
(Effect of lysozyme in high temperature zone at high temperature)
In the production process of retort foods and the like, it is considered that the temperature of the fluidized food becomes high. In the case of stearothermophilus, it is necessary to achieve the bacteriostatic effect by lysozyme even at the growth limit temperature of 70 ° C. Therefore, the bacteriostatic effect of lysozyme in the high temperature zone was confirmed. B.
Since coagulans can only grow up to 60 ° C, the experiment was stearothe
Performed on rmophilus.
The experiment was conducted as described in Example 1 except that static culture was performed at 70 ° C. in a thermostatic bath. stearo
The experiment was carried out in the same manner as in the experimental group inoculated with thermophilus. B. After each predetermined time has elapsed. Table 2 shows the numbers of stearothermophilus bacteria and their changes.
And shown in FIG.

As shown in Table 2 and FIG. 4, B.B.
It was possible to inhibit the growth of stearothermophilus. At the same time, the performance of the white sauce was equivalent to that in the experimental section containing lysozyme in Example 1.

Example 3
(Effect of lysozyme under aerobic conditions)
In the production process of retort foods, etc., it is considered that fluid foods are placed under aerobic conditions at various processing facilities, and the bacteriostatic effect of lysozyme needs to be achieved even under such conditions. There is. Therefore, the bacteriostatic effect of lysozyme under aerobic conditions was confirmed.
Each experiment in Example 1 was conducted except that static culture was replaced with shaking culture in a high-temperature bath equipped with a shaker at 55 ° C. under conditions of 80 times / minute (the liquid level slightly fluctuates). It carried out similarly about the white sauce similar to the thing of an experimental section. Table 3 and FIGS. 5 and 6 show the number of thermophilic bacteria and their changes after the passage of each predetermined time.

As shown in Table 3 and FIGS. 5 and 6, even under aerobic conditions, the white sauce containing egg white lysozyme is free of thermophilic bacteria after 4 to 16 hours regardless of the lysozyme concentration. Growth was suppressed and a bacteriostatic effect was clearly observed (in FIG. 5, no growth of B. coagulans was observed in any of those added with egg white lysozyme).
At the same time, the performance of the white sauce was equivalent to that in the experimental section containing lysozyme in Example 1.

In the above experiment, the number of primary bacteria when inoculating food was excessive compared to the number of bacteria considered to be mixed in processing equipment such as normal food. Furthermore, it is considered that an environment in which thermophilic bacteria are likely to proliferate is selected and processing of ordinary foods or the like is a more disadvantageous condition for the growth of thermophilic bacteria. Therefore, under the conditions in each of the experiments described above, the induction period of the growth of thermophilic bacteria was usually 4 hours, but could be extended to 16 hours. Therefore, even in normal processing, at least 16 hours. To the extent, it can be said that the growth of thermophilic bacteria can be sufficiently suppressed. According to this, when foods, beverages, pharmaceuticals, etc. to which lysozyme is added at 50 ppm or more, for example, are processed, continuous production of about 16 hours or more can be performed without deterioration in quality.

FIG. 1 is a schematic view showing an embodiment of a retort food sterilizing apparatus to which the present invention is applied. FIG. 2 shows B. cultivars after incubation at 55 ° C. for a predetermined time. The number of bacteria of coagulans and its change are shown. FIG. 3 shows B. cultivars after incubation at 55 ° C. for a predetermined time. The number of stearothermophilus and its change are shown. FIG. 4 shows B.B. after culture at 70 ° C. for a predetermined time. The number of stearothermophilus and its change are shown. FIG. 5 shows B.B. The number of bacteria of coagulans and its change are shown. FIG. 6 shows B. cultivars after culturing at 55 ° C. under aerobic conditions for a predetermined time. The number of stearothermophilus and its change are shown.

Explanation of symbols

A sterilizer, B liquid food, C container, 1 cooking pot, 2 pump, 3 filling machine,
4 piping, 5 retort heat sterilization, 7 connecting parts

Claims (2)

A bacteriostatic method for a processing facility, wherein the processing facility is treated with a fluid substance containing a concentration of lysozyme sufficient to suppress the growth of thermophilic bacteria, thereby suppressing the growth of thermophilic bacteria in the processing facility. In the processing facility, by treating the fluid substance containing lysozyme at a concentration sufficient to suppress the growth of thermophilic bacteria, the growth of the thermophilic bacteria in the processing facility is suppressed, and during the treatment, the fluid substance A method for producing a sterilized fluid substance characterized by subjecting to heat sterilization treatment.