{"id":199,"date":"2020-11-02T03:54:01","date_gmt":"2020-11-02T08:54:01","guid":{"rendered":"https:\/\/www.cd-bioparticles.com\/blog\/?p=199"},"modified":"2020-11-02T03:54:01","modified_gmt":"2020-11-02T08:54:01","slug":"magnetic-particles-help-to-detect-foodborne-pathogens","status":"publish","type":"post","link":"https:\/\/www.cd-bioparticles.com\/blog\/magnetic-beads\/magnetic-particles-help-to-detect-foodborne-pathogens\/","title":{"rendered":"Magnetic Particles Help to Detect Foodborne Pathogens"},"content":{"rendered":"\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img loading=\"lazy\" decoding=\"async\" width=\"612\" height=\"408\" src=\"\/blog\/wp-content\/uploads\/2020\/11\/Magnetic-Particles-Help-to-Detect-Foodborne-Pathogens-3.png\" alt=\"\" class=\"wp-image-202\" srcset=\"\/blog\/wp-content\/uploads\/2020\/11\/Magnetic-Particles-Help-to-Detect-Foodborne-Pathogens-3.png 612w, \/blog\/wp-content\/uploads\/2020\/11\/Magnetic-Particles-Help-to-Detect-Foodborne-Pathogens-3-300x200.png 300w, \/blog\/wp-content\/uploads\/2020\/11\/Magnetic-Particles-Help-to-Detect-Foodborne-Pathogens-3-120x80.png 120w\" sizes=\"auto, (max-width: 612px) 100vw, 612px\" \/><\/figure><\/div>\n\n\n\n<p>In\nMarch 2020, Professor Sung Yang from School of Mechanical Engineering, GIST, Republic\nof Korea and his colleagues published an article about magnetophoresis-based\nmicrofluidic device for sample concentration of foodborne pathogens on <em>Food\nControl<\/em>. Let\u2019s see what they have studied.<\/p>\n\n\n\n<p>The detection\nof foodborne pathogens is mainly with the help of medical, physical and\nchemical, biological, and other methods to comprehensively and deeply analyze\nthe impact of microorganisms on human health. Scientific and effective foodborne\npathogen test can timely grasp the situation of food contamination, determine\nwhether food is safe or not, let people eat healthy and safe food, and avoid\nunnecessary economic losses and adverse social effects. Foodborne bacteria\nconstitute a major public health problem in the world. CDC estimates that each\nyear roughly 1 in 6 Americans (or 48 million people) gets sick, 128,000 are\nhospitalized, and 3,000 die of foodborne diseases. At the same time, if there\nis no foodborne pathogen test, once there is a food safety accident, it is very\ndifficult for medical staff to find out the cause timely and accurately,\naffecting the patient&#8217;s physical recovery. Accurate and complete foodborne\npathogen test data can also provide an evaluation basis for hygiene.<\/p>\n\n\n\n<p>Therefore, foodborne\npathogen test is very important, and it must be carried out in strict\naccordance with relevant laws and regulations to minimize errors, ensure the\naccuracy and timeliness of test data, and really provide consumers with healthy\nand safe food. Finally, through the foodborne pathogen test, we can determine\nwhether the whole food processing environment and process is up to the standard.\nAccording to the test results, we can also determine the degree of food\ncontamination by bacteria in time, providing a basis for relevant departments\nto carry out health management work, and effectively preventing the occurrence\nof accidents such as food poisoning and infectious diseases. And it can also\nenable relevant departments to make targeted preventive measures and emergency\nplans in time.<\/p>\n\n\n\n<p>The available\nmethods for the detection of the foodborne pathogens:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Culture-based method<\/li><\/ul>\n\n\n\n<p>The culture-based method is the oldest method for detecting\nmicroorganisms and even pathogens. This method gives definite results regarding\nthe presence of specific pathogens. This method has a high success rate and is\ncost-effective. However, the biggest disadvantage of the culture-based method\nis slow growth. Due to the slow growth, it takes too much time to obtain the\nfinal result (often 18-24 hours), which may prove to be fatal.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Immunoassays<\/li><\/ul>\n\n\n\n<p>Immunoassays were developed because they are easier to perform, gave\nfaster results, and were cheaper. Therefore, an immunoassay is usually\nperformed before a polymerase chain reaction (PCR)-based method. Enzyme-linked\nimmunosorbent assay (ELISA) is one of the most widely used immunoassays so far.\nAntibody purity plays an important role in the success of immunoassays. In\naddition to purity, another factor that affects detection is the specificity of\nthe antibody. Polyclonal antibodies are polyvalent (can react with multiple\nepitopes). This affects the assay, resulting in lower specificity and\nsensitivity. It must also be noted that this method may have false-positive\nresults.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>PCR-based method<\/li><\/ul>\n\n\n\n<p>The main advantages of PCR are rapid and sensitive. It is faster\nthan culture-based methods and immunoassays. It only takes 30 minutes to obtain\nthe amplified product, and because multiple pairs of primers are used, the\ndistinction between strains becomes much easier. With the lower detection limit\nof DNA amplicons as low as femtograms (10<sup>-15 <\/sup>g), the detection limit\nof PCR can reach even lower. The PCR method can replace the tedious and\ntime-consuming pathogen cultivation and identification procedures in food\nsafety laboratories. But its difficulties include cell lysis and nucleic acid\nextraction, cross-contamination, and reaction failure due to the presence of\ninhibitory substances or competing DNA from non-target cells. This can lead to\ninconsistent results and reduce the appeal of PCR as a reliable method.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Biosensors<\/li><\/ul>\n\n\n\n<p>The biosensor is the latest of all detection systems, some of which have\nbetter detection limits, greatly reducing and eliminating the disadvantages\nassociated with PCR technology. A biosensor is a device used for pathogen\ndetection. It usually includes three elements, namely, biological capture\nmolecules (probes and antibodies), methods to convert capture molecule-target\ninteractions into signals, and output data. Although the detection efficiency\nis higher, the results obtained using molecular biology methods may be affected\nby various food matrices.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Other methods<\/li><\/ul>\n\n\n\n<p>DNA microarrays are currently receiving more and more attention due\nto their rapid, sensitive, specific, high-throughput analysis and other\nadvantages, and have become a useful analysis tool. Other commonly used methods\ninclude ultrafiltration, immunomagnetic assays (IMS), immunochromatic assay\n(ICA), flow cytometry (FC), and lyophilization.<\/p>\n\n\n\n<p>Methods\nsuch as cell culture, PCR, and immunoassay require skilled operators and\nexpensive equipment. Therefore, to detect quickly, accurately, and simply,\nvarious biosensors have been developed. Most biosensors use a small amount of\nsamples (a few tens of microliters) to detect bacteria. However, in Korea, the\nmaximum acceptable limit for bacterial contaminants is 0 CFU\/mL. Therefore, it\nis necessary to use at least a few milliliters of samples for bacterial testing\nto obtain statistically significant results. A small amount of\nlow-concentration samples may cause false-negative results in bacterial tests\nbecause these samples may not contain bacteria. In this case, multiple tests\nmust be performed to process a statistically significant volume of the sample\n(a few milliliters). In addition, the detection limit of most biosensors is\nvery low, about 10<sup>1<\/sup>-10<sup>2<\/sup> CFU\/mL, which is still higher\nthan the bacterial detection criterion for food samples. Therefore, it is\nnecessary to concentrate food samples from a few milliliters to a few tens of\nmicroliters to obtain results that meet the criterion. At the same time,\nreducing the sample size can enhance statistical significance. Therefore, sample\npretreatment (such as bacterial concentration) is essential for the rapid and\naccurate detection of foodborne bacteria.<\/p>\n\n\n\n<p>In order to\nshorten the sample pretreatment time, the magnetophoresis-based bacteria\nconcentration devices have been extensively studied. The target sample can be\nlabeled with various biologically active groups combined with magnetic\nparticles (MPS). MP-binding bacteria (MP\/Bac) can be separated from the food\nmatrix by an external magnetic field. In particular, the continuous sample pretreatment\ndevice based on microfluidic technology has been extensively studied in order\nto achieve rapid sample concentration. Professor Yang said, &#8220;The\nmicrofluidic platform presents multiple advantages such as small size,\nportability, low cost, and easy integration with various types of devices.\nHowever, most magnetophoresis-based concentration devices are fabricated as\ntwo-dimensional structures and have very short channel lengths. Therefore, the\nMPs cannot sufficiently move toward the channel wall near the magnet under high\nflow rate conditions, limiting the separation efficiency.&#8221; In addition,\nsince the microfluidic channel and the magnet should be placed in a\ntwo-dimensional space, therefore, as the channel length increases, the device\nsize and the distance between the channel and the magnet will also increase.\nThus, the continuous bacterial concentration device based on the\nmagnetophoresis method has low throughput.<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"438\" src=\"\/blog\/wp-content\/uploads\/2020\/11\/Magnetic-Particles-Help-to-Detect-Foodborne-Pathogens-2-1024x438.png\" alt=\"\" class=\"wp-image-200\" srcset=\"\/blog\/wp-content\/uploads\/2020\/11\/Magnetic-Particles-Help-to-Detect-Foodborne-Pathogens-2-1024x438.png 1024w, \/blog\/wp-content\/uploads\/2020\/11\/Magnetic-Particles-Help-to-Detect-Foodborne-Pathogens-2-300x128.png 300w, \/blog\/wp-content\/uploads\/2020\/11\/Magnetic-Particles-Help-to-Detect-Foodborne-Pathogens-2-768x328.png 768w, \/blog\/wp-content\/uploads\/2020\/11\/Magnetic-Particles-Help-to-Detect-Foodborne-Pathogens-2.png 1317w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption> Figure 1. Schematic of the continuous bacteria concentration device (left) and detail of the device (right). The device consists of a permanent magnet, support structure, polyethylene tube, and PDMS channel. The MP\/Bac injected with a flow rate of 40 mL\/h move to the inner wall of the channel and flow out through outlet 1.  <\/figcaption><\/figure><\/div>\n\n\n\n<p>Yang and his team developed a magnetophoresis-based microfluidic device to achieve rapid and continuous concentration of bacteria (Figure 1). The device is a three-dimensional structure composed of a commercial polyethylene tube and PDMS channel. By adjusting the length of the channel, the concentration of bacteria at a high flow rate is realized. For example, they conjugated <em>Staphylococcus aureus<\/em> with MPs (protein-A functionalized MPs, <a href=\"https:\/\/www.cd-bioparticles.com\/p\/Absolute-Mag%E2%84%A2-Protein-A-Magnetic-Particles-1-0-%CE%BCm_20_194_233_261.html\">WHM-X032<\/a>, CD Bioparticles, USA) before concentration, and found that the optimal channel length was 12 turns at a flow rate of 40 mL\/h. Experiments with different channel lengths and flow rates with deionized water verified the calculated optimal channel length. When the flow rate was 40mL\/h, the separation efficiency was greater than 96%, and the concentration factor was greater than 110 times. In addition, the performance of the device was evaluated using milk and homogenized cabbage samples. The separation efficiency and concentration factor obtained were greater than 92% and 117 times, respectively. However, due to the sudden expansion of the structure, the flow at the junction of the tube and the PDMS channel became unstable at high flow rates, so the performance of the proposed device was decreased. This problem can be overcome by using tubes of different diameters and designing the PDMS channel structure to reduce the associated vortex. In addition, the device can be easily tuned by adjusting the number of turns of the tube channel. Therefore, the device is expected to be used for bacterial concentration under high flow conditions in the fields of food, medicine, and industry. <\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>Reference:<br>Jung, T., Jung, Y., Ahn, J., &amp; Yang, S. (2020). Continuous, rapid concentration of foodborne bacteria (Staphylococcus aureus, Salmonella typhimurium, and Listeria monocytogenes) using magnetophoresis-based microfluidic device. <em>Food Control<\/em>, 107229. <\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>In March 2020, Professor Sung Yang from School of Mechanical Engineering, GIST, Republic of Korea and his colleagues published an<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7,6],"tags":[52,4,47],"class_list":["post-199","post","type-post","status-publish","format-standard","hentry","category-applications","category-magnetic-beads","tag-foodborne-pathogens","tag-magnetic-particles","tag-microfluidic-technology"],"_links":{"self":[{"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/posts\/199","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/comments?post=199"}],"version-history":[{"count":2,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/posts\/199\/revisions"}],"predecessor-version":[{"id":203,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/posts\/199\/revisions\/203"}],"wp:attachment":[{"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/media?parent=199"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/categories?post=199"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.cd-bioparticles.com\/blog\/wp-json\/wp\/v2\/tags?post=199"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}