The biofilm formation on equipment surfaces in dairy manufacturing is a major concern for industry and consumers alike, which may affect the safety and quality of dairy products. In order to identify the bio-contamina...The biofilm formation on equipment surfaces in dairy manufacturing is a major concern for industry and consumers alike, which may affect the safety and quality of dairy products. In order to identify the bio-contamination risk of materials commonly used in dairy manufacturing,</span><span style="font-family:""> </span><span style="font-family:Verdana;">adhesion of </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Staphylococcus aureus</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> on glass coated by two kinds of UHT milk (whole milk and skimmed milk) was investigated. It is known that adhesion is mainly governed by surface physicochemical properties, for that,</span><span style="font-family:""> </span><span style="font-family:Verdana;">the effect of milk components on physicochemical properties of glass and bacterial surfaces were exanimated through contact angle measurements. MATLAB software was used to evaluate the ability of </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">S.</span></i><i><span style="font-family:""> </span></i><i><span style="font-family:Verdana;">aureus</span></i><i><span style="font-family:Verdana;"></i></span></i><i><span style="font-family:""> </span></i><span style="font-family:Verdana;">adhesion on glass.</span><span style="font-family:""> </span><span style="font-family:Verdana;">The hydrophobic quantitative and electron acceptor characteristics of the glass appear to increase with the presence of fat in milk, while its electron donor property</span><span style="font-family:""> </span><span style="font-family:Verdana;">decreases with this component. The percentage of occupied surface of untreated glass was more important than in treated surfaces for 50% of the strains studied.</span><span style="font-family:""> </span><span style="font-family:Verdana;">As well, the percentage of occupied surface by bacterial strains in untreated glass by skimmed milk is generally more important compared to the whole milk. Therefore, the risk of bio-contamination of untreated glass is more favorable for bacteria cultured in skimmed milk compared to these in whole milk but the bio-contamination risk on covered glass by milk is not milk dependent and is strain dependent.展开更多
To improve the start-up speed and efficiency of bioreactors, biofilm technology is sometimes used. This technology uses various types of materials to facilitate the adhesion of microorganisms. In this study, the surfa...To improve the start-up speed and efficiency of bioreactors, biofilm technology is sometimes used. This technology uses various types of materials to facilitate the adhesion of microorganisms. In this study, the surface characteris<span style="font-family:Verdana;">tics of inert substrates and substrates after olive oil-mill wastewater (OMWW)</span><span style="font-family:Verdana;"> conditioning film were evaluated to understand the impact of OMWW on adhesion as well as the most suitable material to optimize bacterial adhesion. Three common substrates made of different polymers were tested for bacterial adhesion before and after treatment with OMWW: PP (polypropylene), PET (Polyethylene terephthalate), and PVC (polyvinyl chloride). The </span><span style="font-family:Verdana;">surfaces’ physicochemical characteristics were studied by measuring the contact angle for the studied bacteria strain and the supports, before and after treatment with OMWW. Results of initial adhesion tests for untreated and treated supports showed differences in how bacterial cells adhered to substrates. Before treatment with OMWW, PVC and then PP showed a significant adhesion capacity, double that of PET [PVC: 1.58</span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">× 10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">, PP: 1.48</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">× 10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and PET: 0.72</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">× 10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">]. After treatment with OMWW, initial bacterial adhesion increased by 10</span><sup><span style="font-family:Verdana;">6</span></sup><span style="font-family:Verdana;"> (from 10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> for untreated supports to 10</span><sup><span style="font-family:Verdana;">11</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> for treated supports), and PET followed by PP demonstrated the highest adhesion capacity, 2 and 1.7 times more than PVC, respectively [PET: 1.39</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">× 10</span><sup><span style="font-family:Verdana;">11</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">, PP: 1.15</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">× 10</span><sup><span style="font-family:Verdana;">11</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and PVC: 0.67</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">× 10</span><sup><span style="font-family:Verdana;">11</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">].</span><a name="_Hlk36219009"></a><span style="font-family:Verdana;"> OMWW conditioning film affects the physicochemical characteristics of plastic supports, especially the donor electron character, and improves the initial adhesion of bacteria to substrates (10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> to 10</span><sup><span style="font-family:Verdana;">11</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">). Therefore, surfaces’ physicochemical characteristics were important in the initial adhesion of the bacteria onto the support before and after treatment.</span></span>展开更多
文摘The biofilm formation on equipment surfaces in dairy manufacturing is a major concern for industry and consumers alike, which may affect the safety and quality of dairy products. In order to identify the bio-contamination risk of materials commonly used in dairy manufacturing,</span><span style="font-family:""> </span><span style="font-family:Verdana;">adhesion of </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Staphylococcus aureus</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:Verdana;"> on glass coated by two kinds of UHT milk (whole milk and skimmed milk) was investigated. It is known that adhesion is mainly governed by surface physicochemical properties, for that,</span><span style="font-family:""> </span><span style="font-family:Verdana;">the effect of milk components on physicochemical properties of glass and bacterial surfaces were exanimated through contact angle measurements. MATLAB software was used to evaluate the ability of </span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">S.</span></i><i><span style="font-family:""> </span></i><i><span style="font-family:Verdana;">aureus</span></i><i><span style="font-family:Verdana;"></i></span></i><i><span style="font-family:""> </span></i><span style="font-family:Verdana;">adhesion on glass.</span><span style="font-family:""> </span><span style="font-family:Verdana;">The hydrophobic quantitative and electron acceptor characteristics of the glass appear to increase with the presence of fat in milk, while its electron donor property</span><span style="font-family:""> </span><span style="font-family:Verdana;">decreases with this component. The percentage of occupied surface of untreated glass was more important than in treated surfaces for 50% of the strains studied.</span><span style="font-family:""> </span><span style="font-family:Verdana;">As well, the percentage of occupied surface by bacterial strains in untreated glass by skimmed milk is generally more important compared to the whole milk. Therefore, the risk of bio-contamination of untreated glass is more favorable for bacteria cultured in skimmed milk compared to these in whole milk but the bio-contamination risk on covered glass by milk is not milk dependent and is strain dependent.
文摘To improve the start-up speed and efficiency of bioreactors, biofilm technology is sometimes used. This technology uses various types of materials to facilitate the adhesion of microorganisms. In this study, the surface characteris<span style="font-family:Verdana;">tics of inert substrates and substrates after olive oil-mill wastewater (OMWW)</span><span style="font-family:Verdana;"> conditioning film were evaluated to understand the impact of OMWW on adhesion as well as the most suitable material to optimize bacterial adhesion. Three common substrates made of different polymers were tested for bacterial adhesion before and after treatment with OMWW: PP (polypropylene), PET (Polyethylene terephthalate), and PVC (polyvinyl chloride). The </span><span style="font-family:Verdana;">surfaces’ physicochemical characteristics were studied by measuring the contact angle for the studied bacteria strain and the supports, before and after treatment with OMWW. Results of initial adhesion tests for untreated and treated supports showed differences in how bacterial cells adhered to substrates. Before treatment with OMWW, PVC and then PP showed a significant adhesion capacity, double that of PET [PVC: 1.58</span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">× 10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">, PP: 1.48</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">× 10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and PET: 0.72</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">× 10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">]. After treatment with OMWW, initial bacterial adhesion increased by 10</span><sup><span style="font-family:Verdana;">6</span></sup><span style="font-family:Verdana;"> (from 10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> for untreated supports to 10</span><sup><span style="font-family:Verdana;">11</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> for treated supports), and PET followed by PP demonstrated the highest adhesion capacity, 2 and 1.7 times more than PVC, respectively [PET: 1.39</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">× 10</span><sup><span style="font-family:Verdana;">11</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">, PP: 1.15</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">× 10</span><sup><span style="font-family:Verdana;">11</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and PVC: 0.67</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">× 10</span><sup><span style="font-family:Verdana;">11</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">].</span><a name="_Hlk36219009"></a><span style="font-family:Verdana;"> OMWW conditioning film affects the physicochemical characteristics of plastic supports, especially the donor electron character, and improves the initial adhesion of bacteria to substrates (10</span><sup><span style="font-family:Verdana;">5</span></sup><span style="font-family:Verdana;"> to 10</span><sup><span style="font-family:Verdana;">11</span></sup><span style="font-family:Verdana;"> CFU/cm</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">). Therefore, surfaces’ physicochemical characteristics were important in the initial adhesion of the bacteria onto the support before and after treatment.</span></span>
