DD206683A3 - METHOD AND DEVICE FOR DETECTING CONTAMINANTS - Google Patents

Abstract

The invention relates to a method and apparatus for detecting contaminants in the food industry through direct sampling and culturing of the microorganisms contained in the samples. THE OBJECTIVE OF THE INVENTION IS TO REDUCE THE WORK AND DEVICE EFFICIENCY WITHOUT REDUCING THE SAFETY OF THE STATEMENT. THE INVENTION HAS THE OBJECT OF DEVELOPING A METHOD AFTER REDUCE THE TEST PROCESSING TIME AND NUMBER OF WORK STEPS UNLOCKED IN A DEVICE UNITING AND CULTURING SYSTEM. THE PROCESS IS CHARACTERIZED IN THAT THE STUDY SAMPLE USING A PREDETERMINED UNDER PRESSURE OR PISTONS IN THE KULTIVIERUNGSGEFAESS REACHED, with a nutrient medium MIXED UP AND DURING THE CULTURE IN GAS PRODUCTION BY THE INQUIRY ORGANISMS equivalent MEASURABLE QUANTITIES OF nutrient-KEIM SUSPENSION LEAKS. AT THE SAME TIME, GROWTH, EDUCATION AND GAS FORMATION OF THE CONTAMINATION ORGANISMS ARE VALUABLE. THE CANNULA OF THE COMBINED SAMPLING CULTURING TREATMENT IS FORMED AS AN INTAKE AND OUTLET. OUTSIDE THE CULTIVATION FAIR, ONE OR MORE SOLID FOODS MADE FROM THE LIQUID NEEDLE MEDIUM ARE DISCONTINUED IN A SPECIALIZED GLASS GASFAQ.

Description

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applicant:

Or. Schade, Werner Laube, Klaus Schambach, Martin Yearly, Annelore Kunz, Artür Strobel, Brigitte

Delivery Agent: VEB Institute Technical Glass Jena Central Office for Property Rights 6300 Ilmenau Postfach 303

IPK: C 12 <i,

Method and device for the detection of contraindications

Field of application of the invention:

The method according to the invention and the device for the detection of contaminants serve both the sampling of the liquid and the cultivation of the microorganisms contained in the samples for the microbiological-hygienic control in establishments of the food industry and similar branches of industry.

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Characteristic of the known technical solutions:

To Wachweis of contaminants various methods are known which are characteristic of the germ load of a product or a Gerätebzw. In principle, however, the method is carried out in several work steps. The removal of a specific sample volume of a liquid or suspension in the laboratory takes place from a container by means of a sterile device (eg a pipette) in order to test. Share the sample cultures on suitable solid and / or liquid nutrients * This container may, for. Eg a beverage bottle or a transport container into which a sample is filled outside the laboratory under sterile conditions. The evaluation of the sample by means of the microscopic image is only possible with a higher contamination. By the number of devices required and the contact with the Ambient air carries the risk of secondary contamination.

For durability control z. B * of beverages is an important factor of the contaminants even in very small numbers. · For this purpose, a larger sample volume is filtered through a membrane and placed on a solid nutrient medium.

In 'cultural methods, however, a satisfactory result can be found at the earliest after three to four days of incubation, since sensitive germs grow more slowly on solid nutrient medium than in liquid cultures. The latter also applies to the known Koch'sehe plate method ·

Sine staining of the microorganisms retained by membrane filters and their subsequent counting and characterization by means of the microscope is only possible in well-equipped workplaces and requires a corresponding qualification. In addition, only a limited distinction can be made in direct counting between vital and dead germs.

Another significant disadvantage of conventional methods is that apart from the degree of contamination, it is also not possible at the same time to determine characteristic properties of the contaminating organisms (gas formation, fermentation activity, acid formation, growth under anaerobic conditions).

For germs that are important in the food industry and similar industries, the simultaneous demonstration of an ability to form gas and acid under aerobic conditions and under

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To grow anaerobic conditions, especially important. According to the conventional procedure, the formation of gas is either qualitatively detected or a separate culture apparatus (eg fermentation tube) is required. Conventional procedures put pressure on laboratories to provide sterilized equipment and nutrient media supply.

Furthermore, certain methods and systems are known from medicine for blood sampling and further processing of blood samples. According to the patents US Pat. No. 3,560,661 and DE-OS No. 2,835,101, it is possible to connect pre-evacuated test tubes to cannula systems which have been pricked into the vein of the patients, which serve either as a container for sample transport or as vessels for biochemical reactions or culture vessels can. According to DS-OS 24-11651, a gas formation is indicated by a pressure-sensitive, gas-impermeable barrier within the blood collection system, a possibility of connection for gas analysis consists · A combined blood collection and culture system for the investigation of bacteremia according to DE-OS 3012056 allows the simultaneous cultivation on solid and liquid nutrient media, wherein the blood is metered into a metered with vacuum or a gas filling vessel of a blood culture system, thereby inoculating both the liquid nutrient medium and the solid culture medium. A pH-dependent indicator visualizes acid formation associated with growth.

The incubation takes place in an inclined position of the system, whereby the withdrawal cannula remains closed with a sterile elastomer stopper. However, these systems are not applicable to the food industry.

Object of the invention:

The aim of the invention is to provide a method and a device for microbiological examination of products and equipment of the food industry and related branches, which do not adhere to the disadvantages of the previous solutions and with their help quantitatively a quick, combined detection of the degree of contamination and essential properties of the Contaminants is also possible when used as disposable containers.

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Statement of the essence of the invention:

The invention has for its object to develop a method that makes the microbiological control safer while reducing the labor and time required and to provide a device that precedes all the necessary functions of sampling and cultivation, so that when using appropriate liquid and / or or solid nutrient media a detection of contaminants in liquids or * of suspended in liquids by known methods microorganisms is possible.

The method according to the invention is preferably suitable for the detection of bacteria, yeasts and molds, in which the liquid sample is metered into a combined sample cultivation vessel provided with reduced pressure and / or a special gas filling (eg CO.sub.2, Ng) and then mixed with the liquid Nutrient medium is mixed ·

One or more solid nutrient media may be incorporated in a separate section of the device, whereby it is possible for the sample mixed with the liquid nutrient medium to simultaneously inoculate the liquid and solid or solid nutrient media * at a particular temperature and vertical position of the vessel the cultivation of the microorganisms, whose growth is recognizable by turbidity of the liquid nutrient medium or by colony or lawn growth on solid nutrient media. The acidifying ability of the contaminating microorganisms is manifested by color change of a pH-dependent indicator system, preferably bromocresol green (3'.5 'x 3 "x 5" tetrabromo-m-cresolsulfonephthalein) or bromophenol blue (tetrabromophenolsulfonephthalein). According to the invention, the process is thereby characterized in that a gas formation of the microorganisms is detected by the vessel is fixed in a suitable stand in a vertical position with the open cannula down, so that a gas formation adequate volume of Nähriuderium microorganism suspension is displaced from the vessel, which in a calibrated , preferably sterile, closed with a sterile cotton plug tube is determined ·

According to the invention, the method is further characterized in that at the same time side by side characteristic properties of Kont.aminationsorganismen such. B. germ content, gas formation, fermentation

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Did or acid formation can be determined. This also makes it possible to test the fermentation activity of the production yeast used by means of the method.

For separate examinations, a sample is taken from the collection tube as well as after cultivation either from the liquid and / or solid nutrient medium.

The device according to the invention is characterized in that the cannula of the sampling cultivation device is simultaneously formed as a suction for the liquid to be examined and as outlet for the displaced in the formation of gas nutrient medium-seed suspension, preferably has a diameter <3 mui and a sterile plug in In addition, the device is characterized in that the vessel for one or more solid nutrient media outside the vessel for the liquid Nährmediuin, preferably arranged as a separate vessel adjacent to the vacuum or gas-filled tree, and with a holder for the solid nutrient medium is provided.

The advantages of the method and the device according to the invention are that it allows the invention to represent a simultaneous detection of gas-forming and acid-forming microorganisms. Compared to the known proposed method, it is thereby advantageously used in the fermentation and beverage industry and similar industries Devices, the attachment of a separate gas sampling device is not necessary, since the gas formation is indicated due to the leakage of the nutrient medium through the sampling pipe ·

Compared to known methods, in the case of the presence of gäraktive yeasts during the incubation samples for further investigation can be taken ·

The system is not only suitable for detecting contamination germs but also for determining the fermentation activity of production yeasts.

The body for the solid nutrient medium is attached outside the device * After appropriate inoculation of the solid nutrient medium, the nutrient medium is incubated standing. Colony formation is thus immediately recognizable. Another advantage of this device is that there is hardly any contamination of the sample material compared to conventional methods and methods.

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can occur because the media to be examined by direct sampling z · D * by piercing membranes for sampling purposes.

Embodiment:

The method and the device according to the invention will be illustrated and explained in the following using examples.

1 is a graph of the gas formation of the germs in a soft drink,

FIG. 2 is a graph of the gas formation of the germs in a soda base. FIG.

3 shows the device according to the invention for various applications:

a open vascular system with a piston for liquid nutrient medium b open vascular system with a piston for liquid and solid nutrient medium

Fig. 4 · a closed vascular system for liquid Nuhrmedium

b closed vascular system for liquid and solid nutrient medium

With the simultaneous detection of fermenting and acid-forming organisms in a soft drink, the beverage must be decarbonic acidified before testing for contaminants, as is common in microbiological examinations.

The test sample is mixed with sterile indicator solution, thereby also the indicator used in the nutrient medium of the collection and cultivation system application. The sample is added as much sterile n-sodium hydroxide solution until the color of the indicator is reversed, since the existing acid has been largely neutralized. The intake manifold of the sampling and cultivating device is immersed in the sample to be examined and the connection to the nutrient medium container produced, the negative pressure in it causes an inflow of the examination liquid into the nutrient medium. The inoculated instrument is gently swirled to an intimate mixing of sample and nutrient medium to secure. Then the inoculated device is brought into vertical position and set after draining any drops with the open intake down to an empty sterile, sealed with a sterile cotton plug calibrated measuring vessel, the nozzle through the cotton plug

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passes "

The complete apparatus is incubated in a stand upright at 3O ⁰ C.

As a sample and Entnähmesystem the shape shown in Figure 3 of the device according to the invention, wherein the outlet nozzle is modified and the possibility of the approach of a calibrated graduated measuring vessel for leaking nutrient medium-seed suspension is. Daily, the turbidity of the liquid nutrient medium, the volume of nutrient medium-seed suspension displaced from the sampling cultivator and the change of the color tone of the indicator are controlled. An examination result is shown in FIG. 1.

With simultaneous detection of fermenting and acid-forming organisms in a lemonade base material is diluted with sterile water prior to the study, analogously to the above procedure with sterile indicator solution and the pH adjusted by means of sterile η-sodium hydroxide solution. The following sedimentation steps take place as mentioned above. · The dilution factor must be taken into account when determining the microbial load · A test result is shown in FIG.

In detecting coliform bacteria, the harvesting culture system is filled with a special nutrient medium, eg Gentiana bile lactose solution. The preparation of the samples and the filling of the liquid to be examined and the subsequent incubation of the germs are also carried out as described.

By a piston or by the negative pressure in the system, a precisely fixed sample amount is sucked into the sampling cultivator, z. B. 1 ml or 5 ml. After incubation and evaluation of the sample, the result shows no Coliformentiter negative in 1 ml or 5 ml sample volume in the absence of gas formation.

The device for detecting contaminants is known to consist of the culture vessel 1 with a breaking off a break-off glass tip 2 and cannula 3. This cannula 3 is also designed as a suction for the liquid sample to be examined and as a discharge nozzle for displaced in the formation of gas nutrient medium-seed suspension It preferably has a diameter of <3 mm and is held upright in a graduated measuring vessel 4r after culturing via a sterile plug 13. The culture vessel 1 contains liquid nutrient medium 5, while outside this vessel 1 there is a glass vessel 10 for one or more solids

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Nähruiedien 6 is arranged. This vessel 10 is preferably located as a separate vessel next to the vacuum- or gas-filled tree 9 uad is provided with a holder 11 for the solid nutrient medium 6 · For germination of the incubated solid culture medium 6 sampling takes place from the glass vessel 10 by this at the breaking ring. 8 is opened.

Claims (4)

-, - 231829 7 Claim A process for the detection of contaminants in the food industry wherein keiwhaltige liquids or liquids, in which germs are introduced for the purpose of investigation by known methods are mixed in a combined sampling cultivator with a selected amount of nutrient medium, characterized in that the subsequent Cultivation of the nutrient medium-seed suspension over a downwardly open outlet nozzle of the sampling cultivating device, while culture in gas formation by the test organisms equivalent measurable amounts of nutrient medium-germ suspension flow and thereby in conjunction with turbidity and color changes of the indicator-containing Nöhrmediums simultaneously in analog values quantitative statements germination, gas formation, fermentation activity and acidification of the contaminating organisms. 2. The method according to item 1, characterized in that one or more solid Nähriuedien are additionally introduced in a separate part of the culture vessel, after introduction of the liquid to be examined a colony / rasenföriaiges growth of the investigation germs on these solid nutrient media and after culturing samples for microscopic inspection and / or further examination and for the propagation of organisms. 3. Apparatus for detecting contaminants, consisting of a combined sampling and cultivation device with culture vessel, rupturable glass tip, cannula and break-off ring and liquid and solid nutrient medium, characterized in that the cannula (3) at the same time as an intake for the liquid to be examined and as Outlet for the displaced in the formation of gas nutrient medium-seed suspension is formed, preferably has a diameter '3 mm and via a sterile plug (13) in a graduated measuring vessel (4) is supported standing. 4. Apparatus according to claim 3, characterized in that outside the culture vessel (1) for the liquid nutrient medium (5) a glass vessel (10) for one or more solid culture media (6), preferably as a separate vessel in addition to the vacuum or gas-filled tree (9) and provided with a holder (11) for the solid nutrient medium (6). ι .m -. ^