An enrichment device for food microbiology testing
By designing an automated enrichment device, the pre-enrichment and selective enrichment operations are automated using peristaltic pumps and solenoid valves, and enrichment and concentration are achieved through immunomagnetic beads. This solves the problems of cumbersome and time-consuming processes and easy cross-contamination in existing technologies, and improves the efficiency and accuracy of food microbial testing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING YITAI BIOTECH CO LTD
- Filing Date
- 2025-07-31
- Publication Date
- 2026-07-31
AI Technical Summary
Existing food microbiology testing methods involve cumbersome, time-consuming, and labor-intensive pre-enrichment and selective enrichment steps, which are prone to cross-contamination and cannot meet the high-efficiency and automated requirements of food safety testing.
Design an automated enrichment device that includes pre-enrichment bags, transfer bags, and selective enrichment bags. Automated operation is achieved using a peristaltic pump and solenoid valves, and enrichment and concentration are achieved through immunomagnetic beads to avoid cross-contamination.
It realizes the automated enrichment process for food microbiology testing, reduces the intensity of manual operation, avoids cross-contamination, and improves testing efficiency and accuracy.
Smart Images
Figure CN224578249U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of food safety testing technology, specifically relating to an enrichment device for food microbiological testing. Background Technology
[0002] Pathogenic bacteria in food can cause various foodborne illnesses, posing serious threats to human health. Common pathogens such as Salmonella, Escherichia coli, and Listeria can cause acute symptoms such as diarrhea, vomiting, and fever, and even lead to serious consequences such as meningitis, kidney failure, or reactive arthritis. Furthermore, the toxins produced by some bacteria (such as Staphylococcus aureus and Clostridium botulinum) are heat-resistant and can still cause poisoning even after heating. To prevent the harm caused by pathogens, it is necessary to strengthen hygiene management in food processing and adopt advanced testing technologies to ensure food safety. Based on this, my country has established national testing standards for various pathogens, including Salmonella, Cronobacter spp., Listeria monocytogenes, and Shiga toxin-producing Escherichia coli.
[0003] The main challenges in detecting pathogenic bacteria in food lie in the low concentration of target bacteria, their potential damage to their state, severe interference from background bacteria, and the complexity of the food matrix. To overcome these challenges and effectively detect pathogenic microorganisms in food, the food testing field generally employs pre-enrichment and selective enrichment methods to propagate the target pathogenic bacteria to a level that allows for effective and accurate detection. Specifically, because the initial concentration of pathogenic bacteria is extremely low and may be damaged by processing, direct detection is often difficult. Therefore, a pre-enrichment step is necessary to restore their activity and propagate them to a detectable level under non-selective conditions. Simultaneously, a large number of background bacteria often exist in food, competitively interfering with the proliferation of target bacteria. Selective bacteria, on the other hand, balance this competition by optimizing the culture medium and conditions.
[0004] Currently, the national standards implemented in my country include pre-enrichment and selective enrichment steps in the testing methods for various food microorganisms. For example, GB 4789.4-2024, "National Food Safety Standard for Microbiological Examination of Food - Salmonella Examination," includes three steps for testing Salmonella in food: pre-enrichment, selective enrichment, and plate isolation. In the pre-enrichment step, 25 g (mL) of the sample to be tested is homogenized in 225 mL of buffered peptone water (BPW) and incubated for 18 hours. In the selective enrichment step following pre-enrichment, 1 mL of the pre-enriched culture is inoculated into 10 mL of sodium tetrathionate brilliant green enrichment broth (TTB) and incubated for 18 to 24 hours. After the selective enrichment culture is completed, bacterial culture is taken from the TTB enrichment broth and streaked onto a bismuth sulfite (BS) agar plate and a xylose-lysine deoxycholic acid (XLD) agar plate. The final test result is determined based on the observation of colonies grown on each plate.
[0005] For example, GB 4789.40-2024, "National Food Safety Standard for Microbiological Examination of Food - Cronobacter sakazakii Examination," specifies a two-step method for testing Cronobacter spp. (Cronobacter sakazakii) in food: pre-enrichment and enrichment. In the pre-enrichment step, 100 g (mL) of the sample to be tested is homogenized in 900 mL of preheated buffered peptone water (BPW) and incubated for 16 to 18 hours. In the subsequent enrichment step, 1 mL of the enriched culture is transferred to 10 mL of modified lauryl sulfate tryptone broth-vancomycin (mLST-Vm) broth and incubated for 22 to 24 hours.
[0006] However, current detection methods for pre-enrichment and selective enrichment require approximately 40 hours of cultivation, involving multiple steps that are complex, tedious, time-consuming, and inefficient for laboratory personnel. Furthermore, the complexity of these procedures increases the risk of cross-contamination between samples, affecting the accuracy of the results. Overall, the current manual methods for pre-enrichment and selective enrichment in food microbiology testing cannot meet the demands of my country's large-scale food safety testing needs. Therefore, a microbiology enrichment technology that reduces manual labor, increases automation, and avoids unnecessary cross-contamination risks not only overcomes long-standing technical problems in food microbiology testing but also significantly improves risk control and efficiency in food production, distribution, and regulatory processes. Utility Model Content
[0007] Based on the above technical problems, the purpose of this utility model is to provide an enrichment device for food microbiology testing that can reduce the intensity of manual operation, improve the level of automation, and avoid unnecessary cross-contamination risks.
[0008] To achieve the above objectives, this utility model provides the following technical solution:
[0009] An enrichment device for food microbiological testing includes a pre-enrichment bag, a transfer bag, and a selective enrichment bag arranged in sequence. A first passage is provided between the pre-enrichment bag and the transfer bag, the first passage including two independent pipes connecting the pre-enrichment bag and the transfer bag at their respective ends, and a first peristaltic pump and a first solenoid valve are installed on the first passage. A second passage is provided between the transfer bag and the selective enrichment bag, the second passage including two independent pipes connecting the transfer bag and the selective enrichment bag at their respective ends, and a second peristaltic pump and a second solenoid valve are installed on the second passage. The pre-enrichment bag is a self-sealing bag or has a liquid inlet. The selective enrichment bag has a liquid outlet, and both the liquid outlet and the liquid inlet are fitted with sealing caps. The first peristaltic pump, the first solenoid valve, the second peristaltic pump, and the second solenoid valve are electrically connected to a control device.
[0010] Further optimization involves fixing an electromagnet to the outside of the transfer bag and containing immunomagnetic beads inside the transfer bag. The diameter of the immunomagnetic beads is set to be smaller than the inner diameter of either the first or second passage. The electromagnet is electrically connected to the control device.
[0011] Furthermore, the volume of the pre-enrichment bag is larger than the volume of the selected enrichment bag, and the volume of the selected enrichment bag is larger than the volume of the transfer bag.
[0012] Furthermore, the pre-enrichment bags, transfer bags, and selective enrichment bags can all be detachably installed on the support frame or placed in a fixed frame.
[0013] Furthermore, the pre-enrichment bags, transfer bags, and selective enrichment bags are all transparent plastic bags.
[0014] Furthermore, both the first and second passages are made of plastic flexible tubing.
[0015] Furthermore, the first peristaltic pump and the first solenoid valve are respectively installed on two independent pipelines in the first passage; the second peristaltic pump and the second solenoid valve are respectively installed on two independent pipelines in the second passage.
[0016] Compared with existing manual food microbiology testing equipment, this invention has at least the following advantages:
[0017] (1) This utility model automates the pre-enrichment and selective enrichment (or secondary enrichment) steps of food microbiology testing without human intervention.
[0018] (2) The structure of this utility model is completely sealed, so there is no risk of cross-contamination in the pre-enrichment and selective enrichment (or secondary enrichment) steps of food microbiology testing.
[0019] (3) This invention uses immunomagnetic beads, which play a role in enrichment and concentration, and can shorten the time of selective enrichment step and improve efficiency. Attached Figure Description
[0020] Figure 1 A schematic diagram of the structure of three bags and the connecting passage in the middle (the pre-incubation bag is a self-sealing bag);
[0021] Figure 2 A schematic diagram of the structure of three bags and the connecting passage in the middle (the pre-incubation bag has a liquid inlet);
[0022] Figure 3 This is a schematic diagram of the overall structure of the enrichment device;
[0023] Figure 4 This is a schematic diagram of the overall structure of the enrichment device (including immunomagnetic beads and electromagnets).
[0024] Figure 5 This is a schematic diagram of the enrichment device in use (solids are on the fixed frame).
[0025] Figure 6 This is a schematic diagram of the enrichment device in use (solids are on the support frame).
[0026] Figure 7 This is a schematic diagram of the enrichment device in use (the solid is on a fixed frame, and it is equipped with immunomagnetic beads and electromagnets).
[0027] In the diagram, 1. Pre-enrichment bag; 2. Transfer bag; 3. Selective enrichment bag; 4. First peristaltic pump; 5. First solenoid valve; 6. Second peristaltic pump; 7. Second solenoid valve; 8. Electromagnet; 9. Immunomagnetic beads; 10. First access path; 11. Second access path; 12. Inlet; 13. Outlet; 14. Fixing frame; 15. Support frame; 16. Control device. Detailed Implementation
[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.
[0029] Example 1
[0030] An enrichment device for food microbiological testing includes, in sequence, a 250 mL pre-enrichment bag 1 made of transparent plastic bag, a 1 mL transfer bag 2, and a 12 mL selective enrichment bag 3. Figure 1 or Figure 2 As shown, a first passage 10 is provided between the pre-incubation bag 1 and the transfer bag 2. The first passage 10 includes two independent pipes connected at both ends to the pre-incubation bag 1 and the transfer bag 2, respectively. A second passage 11 is provided between the transfer bag 2 and the selective incubation bag 3. The second passage 11 includes two independent pipes connected at both ends to the transfer bag 2 and the selective incubation bag 3, respectively. The independent pipes of the first passage 10 and the second passage 11 are both plastic flexible tubes. A first peristaltic pump 4 and a first solenoid valve 5 are respectively provided on the two independent pipes of the first passage 10; a second peristaltic pump 6 and a second solenoid valve 7 are respectively provided on the two independent pipes of the second passage 11. The pre-incubation bag 1 is a self-sealing bag or has a liquid inlet 12; the selective incubation bag 3 has a liquid outlet 13, and both the liquid outlet 13 and the liquid inlet 12 are fitted with sealing caps.
[0031] like Figure 3As shown, the first peristaltic pump 4, the first solenoid valve 5, the second peristaltic pump 6, and the second solenoid valve 7 are connected to a power supply and electrically connected to a control device 16. The control device includes a display screen, an operation button area, and a microcontroller controller. The power supply can be internal or external. Figure 5 As shown, in this embodiment, the pre-incubation bag 1, the transfer bag 2, and the selective incubation bag 3 can all be detachably placed in a fixed frame 14 during use.
[0032] The method of using this device for enrichment in the detection of Salmonella in food is as follows:
[0033] At the start of the pre-enrichment stage, 225 mL of buffered peptone water (BPW) was added to pre-enrichment bag 1. Transplantation bag 2 was empty. Selective enrichment bag 3 contained 10 mL of sodium tetrathionate brilliant green enrichment broth (TTB). The first solenoid valve 5 was closed, at which point the first peristaltic pump 4 was shut off, and pre-enrichment bag 1 and transplantation bag 2 were no longer connected. 25 g / mL of the sample to be tested was added to pre-enrichment bag 1 for pre-enrichment culture.
[0034] After the pre-incubation stage, the first solenoid valve 5 is opened, at which point the first peristaltic pump 4 is turned on, and the pre-incubation bag 1 and the transfer bag 2 become connected, and 1 mL of culture medium in the pre-incubation bag 1 is introduced into the transfer bag 2.
[0035] Afterwards, the first solenoid valve 5 is closed, at which point the first peristaltic pump 4 is shut down, and the pre-enrichment bag 1 and the transfer bag 2 are no longer connected. Then, the second solenoid valve 7 is opened, and the second peristaltic pump 6 is activated, connecting the transfer bag 2 and the selective enrichment bag 3. 1 mL of the pre-enrichment culture medium in the transfer bag 2 is transferred into 10 mL of sodium tetrathionate brilliant green enrichment broth (TTB) in the selective enrichment bag 3, thus initiating the selective enrichment stage of cultivation.
[0036] After the culture is completed, samples are taken through sampling port 13 to selectively culture plates.
[0037] In this embodiment, the entire device can be placed inside a temperature-adjustable constant temperature chamber. The control device can also be connected to the outside of the constant temperature chamber via wires.
[0038] Example 2
[0039] The difference between this embodiment and Embodiment 1 is that a 1000mL pre-enrichment bag 1, a 1mL transfer bag 2, and a 12mL selective enrichment bag 3 are used. Figure 6 As shown, the pre-incubation bag 1, the transfer bag 2, and the selective incubation bag 3 are all detachably installed inside the support frame 15. The support frame 15 is equipped with hooks and brackets. The hooks can suspend the tops of the pre-incubation bag 1, the transfer bag 2, and the selective incubation bag 3. The control device 16, the first peristaltic pump 4, and the second peristaltic pump 5 are placed on the brackets at the bottom of the support frame 15.
[0040] This device can be used for the enrichment of Cronobacterium in food. In this embodiment, the entire device can be placed in a temperature-controlled incubator. Alternatively, the pre-enrichment bag 1, the transfer bag 2, and the selective enrichment bag 3 can be covered with a heating and temperature-controlled device.
[0041] Example 3
[0042] The difference between this embodiment and Embodiment 1 is that, as Figure 4 As shown, an electromagnet 8 is fixed to the outside of the transfer bag 2, and an immunomagnetic bead 9 is contained inside the transfer bag 2. The diameter of the immunomagnetic bead 9 is set to be smaller than the inner diameter of either the first passage 10 or the second passage 11. The electromagnet 8 is connected to a power source and electrically connected to the control device 16. Its operating state is as follows... Figure 7 As shown.
[0043] The method of using this device for enrichment in the process of detecting Salmonella in food:
[0044] At the start of the pre-enrichment stage, 225 mL of buffered peptone water (BPW) was added to pre-enrichment bag 1, Salmonella immunomagnetic beads were placed in transfection bag 2, and 10 mL of sodium tetrathionate brilliant green enrichment broth (TTB) was placed in selective enrichment bag 3. The first solenoid valve 5 was closed, at which point the first peristaltic pump 4 was shut off, and pre-enrichment bag 1 and transfection bag 2 were no longer connected. 25 g / mL of the sample to be tested was added to pre-enrichment bag 1 for pre-enrichment culture.
[0045] After the pre-enrichment culture stage, the first solenoid valve 5 is opened, at which point the first peristaltic pump 4 is turned on, and the pre-enrichment bag 1 and the transfer bag 2 become connected. At this time, the electromagnet 8 is turned off, and the immunomagnetic beads combine with Salmonella that may be present in the pre-enrichment solution.
[0046] After 20 minutes, the electromagnet 8 is turned on. At this time, the pre-incubation bag 1 and the transfer bag 2 are connected. The culture medium in the pre-incubation bag 1 enters the transfer bag 2 through the operation of the first peristaltic pump 4. At this time, the immunomagnetic bead-Salmonella complex in the liquid is captured by the electromagnet and concentrated at the bottom of the transfer bag 2.
[0047] After capture, the first solenoid valve 5 is closed, at which point the first peristaltic pump 4 is shut off, and the pre-enrichment bag 1 and the transfer bag 2 are disconnected. The electromagnet 8 is then closed. Next, the second solenoid valve 7 is opened, at which point the second peristaltic pump 6 is activated, and the transfer bag 2 and the selective enrichment bag 3 are connected. 1 mL of the pre-enrichment culture medium and the immunomagnetic bead-Salmonella complex in the transfer bag 2 are transferred into 10 mL of sodium tetrathionate brilliant green enrichment broth (TTB) in the selective enrichment bag 3, thus initiating the selective enrichment stage of cultivation.
[0048] After the culture is completed, samples are taken through sampling port 13 to selectively culture plates.
[0049] The above are merely preferred embodiments of the present utility model and are not intended to limit the scope of protection of the present utility model. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the scope of protection of the present utility model.
Claims
1. An enrichment device for food microbiology testing, characterized in that: It includes pre-enrichment bags (1), transfer bags (2) and selective enrichment bags (3) arranged in sequence. A first passage (10) is provided between the pre-incubation bag (1) and the transfer bag (2). The first passage (10) includes two independent pipes that are respectively connected at both ends to the pre-incubation bag (1) and the transfer bag (2). A first peristaltic pump (4) and a first solenoid valve (5) are provided on the first passage (10). A second passage (11) is provided between the transfer bag (2) and the selective enrichment bag (3). The second passage (11) includes two independent pipes that are connected at both ends to the transfer bag (2) and the selective enrichment bag (3) respectively. A second peristaltic pump (6) and a second solenoid valve (7) are provided on the second passage (11). The pre-enrichment bag (1) is a self-sealing bag or is provided with a liquid inlet (12); the selective enrichment bag (3) is provided with a liquid outlet (13), and both the liquid outlet (13) and the liquid inlet (12) are equipped with sealing caps; The first peristaltic pump (4), the first solenoid valve (5), the second peristaltic pump (6), and the second solenoid valve (7) are electrically connected to a control device (16).
2. Enrichment device for microbiological examination of food according to claim 1, characterized in that: An electromagnet (8) is fixed to the outside of the transfer bag (2), and an immunomagnetic bead (9) is contained inside the transfer bag (2). The diameter of the immunomagnetic bead (9) is set to be smaller than the inner diameter of any one of the tubes in the first channel (10) and the second channel (11). The electromagnet (8) is electrically connected to the control device (16).
3. The enrichment device for food microbiology testing according to claim 1, characterized in that: The volume of the pre-enrichment bag (1) is greater than the volume of the selective enrichment bag (3), and the volume of the selective enrichment bag (3) is greater than the volume of the transfer bag (2).
4. The enrichment device for food microbiology testing according to claim 1, characterized in that: The pre-enrichment bag (1), the transfer bag (2), and the selective enrichment bag (3) can all be detachably installed on the support frame (15) or placed in a fixed frame (14).
5. The enrichment device for food microbiology testing according to claim 1, characterized in that: The pre-enrichment bag (1), the transfer bag (2), and the selective enrichment bag (3) are all transparent plastic bags.
6. The enrichment device for food microbiology testing according to claim 1, characterized in that: The independent conduits of the first passage (10) and the second passage (11) are both plastic hoses.
7. The enrichment device for food microbiology testing according to claim 1, characterized in that: The first peristaltic pump (4) and the first solenoid valve (5) are respectively installed on two independent pipelines of the first passage (10); the second peristaltic pump (6) and the second solenoid valve (7) are respectively installed on two independent pipelines of the second passage (11).