{"id":44772,"date":"2021-03-12T10:27:34","date_gmt":"2021-03-12T08:27:34","guid":{"rendered":"https:\/\/www.iemn.fr\/?p=44772"},"modified":"2021-03-12T11:35:13","modified_gmt":"2021-03-12T09:35:13","slug":"methode-ultrasonore-pour-la-detection-et-le-suivi-de-croissance-de-depots-bacteriens-in-situ","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/newsletter\/methode-ultrasonore-pour-la-detection-et-le-suivi-de-croissance-de-depots-bacteriens-in-situ.html","title":{"rendered":"Ultrasonic method for detecting and monitoring the growth of in-situ bacterial deposits"},"content":{"rendered":"<div id='layer_slider_1'  class='avia-layerslider main_color avia-shadow  avia-builder-el-0  el_before_av_one_full  avia-builder-el-first  container_wrap sidebar_right'  style='height: 261px;'  ><div id=\"layerslider_27_1wi9pq4lysogf\" data-ls-slug=\"homepageslider\" class=\"ls-wp-container fitvidsignore ls-selectable\" style=\"width:1140px;height:260px;margin:0 auto;margin-bottom: 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https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/06\/Slider_CMNF4-768x80.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/06\/Slider_CMNF4-1030x107.jpg 1030w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/06\/Slider_CMNF4-1500x156.jpg 1500w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/06\/Slider_CMNF4-705x73.jpg 705w\" sizes=\"auto, (max-width: 2600px) 100vw, 2600px\" \/><ls-layer style=\"font-size:14px;text-align:left;font-style:normal;text-decoration:none;text-transform:none;font-weight:700;letter-spacing:0px;border-style:solid;border-color:#000;background-position:0% 0%;background-repeat:no-repeat;height:30px;top:231px;line-height:32px;color:#ffffff;border-radius:6px 6px 6px 6px;padding-left:50px;background-color:rgba(0, 0, 0, 0.57);width:260px;\" class=\"ls-l ls-ib-icon ls-text-layer\"><i class=\"fa fa-user-circle\" style=\"color:#ffffff;margin-right:0.8em;font-size:1em;transform:translateY( -0.125em );\"><\/i>LA RECHERCHE \u00e0 l'IEMN<\/ls-layer><\/div><\/div><\/div><div id='after_layer_slider_1'  class='main_color av_default_container_wrap container_wrap sidebar_right'  ><div class='container av-section-cont-open' ><div class='template-page content  av-content-small alpha units'><div class='post-entry post-entry-type-page post-entry-44772'><div class='entry-content-wrapper clearfix'>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-1ld53fo-f13a381154a21095222c4f2378725794\">\n.flex_column.av-1ld53fo-f13a381154a21095222c4f2378725794{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-1ld53fo-f13a381154a21095222c4f2378725794 av_one_full  avia-builder-el-1  el_after_av_layerslider  el_before_av_one_half  avia-builder-el-first  first flex_column_div av-zero-column-padding'     ><section  class='av_textblock_section av-km61d5g3-c367a9b14f4a59ce403e665eb6e132e3'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h4 style=\"text-align: center;\">Ultrasonic method for detecting and monitoring the growth of in-situ bacterial deposits<\/h4>\n<hr \/>\n<blockquote>\n<p>The growth of biofilms (clusters of micro-organisms adhering to a surface) is a particularly crucial issue in the food industry. Despite strict sterilisation and decontamination protocols, the formation of these biofilms is sometimes unavoidable and can have pathogenic effects. A method for detecting their appearance and evolution based on ultrasound measurements has recently been proposed at the IEMN, in collaboration with INRAE. The method is totally non-invasive, since detection takes place through the wall of the enclosure containing the medium to be inspected, and has shown promising preliminary results. In addition to biofilms, any change in properties at the solid-liquid interface (e.g. fouling, various deposits, variations in the properties of the medium, etc.) is likely to be detected.<\/p>\n<\/blockquote>\n<\/div><\/section><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-144xukk-57f571234427bd353a1ff71b9781d195\">\n.flex_column.av-144xukk-57f571234427bd353a1ff71b9781d195{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-144xukk-57f571234427bd353a1ff71b9781d195 av_one_half  avia-builder-el-3  el_after_av_one_full  el_before_av_one_half  first flex_column_div av-zero-column-padding  column-top-margin'     ><section  class='av_textblock_section av-km61dq7e-dd9ffe6764ba931d7f6cbce99d129797'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>Conventional ultrasonic detection and imaging methods (such as medical ultrasound or industrial NDT) are based on the transmission and reception of ultrasonic echoes reflected once at the interfaces present in the medium. By analysing these echoes, it is possible to obtain location information or to produce images, provided that the interfaces or objects in question have acoustic properties that are significantly different from those of the surrounding environment (which explains, for example, the fact that in obstetric ultrasound, it is the baby's skeleton that presents the best contrast on the images).<\/p>\n<p>In contrast, in the application presented here, we use ultrasonic multipaths (echoes reflected a very large number of times on the different interfaces of the propagation medium). Unlike ultrasound, this technique does not allow imaging (since the location information is lost), but it is extremely sensitive to even small variations in properties. These multiply reflected echoes are known as \"coda signals\", from the Latin word coda meaning tail (they appear at the end, or \"tail\" of the recorded ultrasound signals).<\/p>\n<p>From these ultrasonic codas, a so-called \"decorrelation\" coefficient is calculated. This coefficient, with values between 0 and 2, reflects the degree of dissimilarity between two signals: 0 corresponds to identical signals and 2 corresponds to unrelated signals. In the absence of any change, coda signals are perfectly reproducible from one measurement to the next. This means that the decorrelation coefficient between one of these signals, measured at a given time, and a so-called reference signal, measured at an earlier time, is close to zero.<\/p>\n<\/div><\/section><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-ojfxyc-f0142df6f922e7ada6888a8d40b7c6c5\">\n.flex_column.av-ojfxyc-f0142df6f922e7ada6888a8d40b7c6c5{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-ojfxyc-f0142df6f922e7ada6888a8d40b7c6c5 av_one_half  avia-builder-el-5  el_after_av_one_half  el_before_av_one_full  flex_column_div av-zero-column-padding  column-top-margin'     ><section  class='av_textblock_section av-km61dym8-f1c4b7e600d3b0ac4b24f7499a407704'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>Conversely, when a change in properties occurs at the substrate-medium interface, variations in the reflection of ultrasound waves modify the coda signals. This results in increasing values of the decorrelation coefficient. Regular measurement of this coefficient enables the evolution of a medium or interface to be monitored over time.<\/p>\n<p>We have used this principle to detect the appearance of a bacterial deposit (biofilm) in a culture medium contained in a tank. The ultrasonic sensor is glued to the outer surface of the tank and is therefore never in contact with the medium. The ultrasonic measurement is made through the wall.<\/p>\n<p>The value of the correlation coefficient between the signal measured at the initial instant and the successive signals at each subsequent instant could be directly correlated to the growth of the bacterial population, as shown in Figure 1. In this figure, graph A shows the evolution of the decorrelation coefficient as a function of time when the tank contains a sterile medium (absence of bacteria and therefore no growth of biofilm on the internal walls of the tank). Graph B shows the evolution of the coefficient in the presence of bacteria in the medium. Comparison of these two graphs clearly shows that the decorrelation coefficient is very sensitive to the growth of the bacterial population, which leads to the formation of a biofilm on the wall. This is confirmed by a measurement of the bacterial concentration over time (graph C).<\/p>\n<\/div><\/section><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-vzf5c4-790d0f9bff4c6e21247afd62cd3f421e\">\n.flex_column.av-vzf5c4-790d0f9bff4c6e21247afd62cd3f421e{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-vzf5c4-790d0f9bff4c6e21247afd62cd3f421e av_one_full  avia-builder-el-7  el_after_av_one_half  el_before_av_one_full  first flex_column_div av-zero-column-padding  column-top-margin'     ><section  class='av_textblock_section av-km61s4sd-c72d1ba530ff99a1ee9c1f6053867dd2'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2021\/03\/image_detecteur3.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-44779\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2021\/03\/image_detecteur3-300x169.jpg\" alt=\"\" width=\"700\" height=\"393\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2021\/03\/image_detecteur3-300x169.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2021\/03\/image_detecteur3-768x432.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2021\/03\/image_detecteur3-16x9.jpg 16w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2021\/03\/image_detecteur3-705x396.jpg 705w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2021\/03\/image_detecteur3.jpg 1000w\" sizes=\"auto, (max-width: 700px) 100vw, 700px\" \/><br \/>\n<\/a><\/p>\n<p style=\"text-align: center;\"><em>Figure 1: Change in decorrelation coefficient as a function of incubation time and comparison with bacterial growth kinetics. (A) Control sample (sterile medium). (B) sample containing bacterial culture medium (C) biofilm formation kinetics (bacterial concentration<\/em><\/p>\n<\/div><\/section><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-jqjnvo-c7e588ec4174734abff97838ff570f30\">\n.flex_column.av-jqjnvo-c7e588ec4174734abff97838ff570f30{\nborder-radius:10px 10px 10px 10px;\npadding:10px 10px 10px 10px;\nbackground-color:#fceed4;\n}\n<\/style>\n<div  class='flex_column av-jqjnvo-c7e588ec4174734abff97838ff570f30 av_one_full  avia-builder-el-9  el_after_av_one_full  el_before_av_one_full  first flex_column_div  column-top-margin'     ><section  class='av_textblock_section av-km61z5r3-103a14b50ea9a26d92d87842b7384914'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p><strong>This method seems particularly promising for non-invasive real-time on-site monitoring of biofilm formation and, more generally, of interface properties (fouling, various deposits, variations in the properties of the medium, etc.).<\/strong><br \/>\nOne of its limitations is its high sensitivity to temperature, which can lead to false positives. This is not a problem in cases where the experimental conditions are thermostatically controlled. In other cases, methods to compensate for the influence of temperature variations on coda decorrelations are currently being studied.<\/p>\n<\/div><\/section><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-jqjnvo-e714d77bc75238207f6ddfab05146ed2\">\n.flex_column.av-jqjnvo-e714d77bc75238207f6ddfab05146ed2{\nborder-radius:5px 5px 5px 5px;\npadding:5px 5px 5px 5px;\n}\n<\/style>\n<div  class='flex_column av-jqjnvo-e714d77bc75238207f6ddfab05146ed2 av_one_full  avia-builder-el-11  el_after_av_one_full  avia-builder-el-last  first flex_column_div  column-top-margin'     ><section  class='av_textblock_section av-km61z5r3-103a14b50ea9a26d92d87842b7384914'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" >\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-13ewzjw-eaff9d3f90dab7dfc562659fb514a1aa\">\n.av_font_icon.av-13ewzjw-eaff9d3f90dab7dfc562659fb514a1aa{\ncolor:#bfbfbf;\nborder-color:#bfbfbf;\n}\n.av_font_icon.av-13ewzjw-eaff9d3f90dab7dfc562659fb514a1aa .av-icon-char{\nfont-size:30px;\nline-height:30px;\n}\n<\/style>\n<span  class='av_font_icon av-13ewzjw-eaff9d3f90dab7dfc562659fb514a1aa avia_animate_when_visible av-icon-style- avia-icon-pos-left avia-icon-animate'><span class='av-icon-char' aria-hidden='true' data-av_icon='\ue881' data-av_iconfont='entypo-fontello' ><\/span><\/span>\n<p>This method is currently the subject of the Interreg-2-Mers SOCORRO project, in which the UPHF (IEMN), INRAE and the University of Lille (UMET) are collaborating.<\/p>\n<p><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2021\/03\/logos_detecteur.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-44788\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2021\/03\/logos_detecteur.jpg\" alt=\"\" width=\"500\" height=\"120\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2021\/03\/logos_detecteur.jpg 600w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2021\/03\/logos_detecteur-300x72.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2021\/03\/logos_detecteur-16x4.jpg 16w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><\/p>\n<\/div><\/section><\/div>","protected":false},"excerpt":{"rendered":"","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[297],"tags":[],"class_list":["post-44772","post","type-post","status-publish","format-standard","hentry","category-newsletter"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/44772","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/comments?post=44772"}],"version-history":[{"count":0,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/44772\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=44772"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=44772"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=44772"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}