Monday, March 23, 2015

Creation of new aluminum surface with bactericidal effect-A nano technology approach

Food contamination inadvertently or through negligence is one of the major challenges to the food industry as well as the safety authorities all over the world.Thousands of innocent consumers are maimed or killed by a dozen highly virulent bacteria and in spite of best of efforts food poisoning continues unabated. Bactericidal processes using heat, chemicals, high pressure, ultra filtration,osmotic pressure, salination, acifdification etc are routinely practiced by the processing industry reducing the episodes of food poisoning to the barest minimum.possible. Consumers still feel that the manufacturers must be more efficient in checkmating pathogens in the foods being offered to them. Scientific community is continuously engaged in a "war of wits" with their tiny adversary, the microbes, which show from time to time remarkable ability to outwit them through mutational changes. The amazing bio-film phenomenon unearthed some time back is a remarkable ploy by these bugs to stick together, attached to a solid surface capable of resisting most of the bactericidal methods to get rid of them. It is against this tendency of some pathogens to form bio-films and contaminate foods that a new strategy has been developed by which the metal contact surfaces are made hostile for the bugs to develop such films. Here is a take on this new exciting development.   

"The technology, developed collaboratively by researchers from Cornell University and Rensselaer Polytechnic Institute, uses an electrochemical process called anodization to create nanoscale pores that change the electrical charge and surface energy of a metal surface, which in turn exerts a repulsive force on bacterial cells and prevents attachment and biofilm formation. These pores can be as small as 15 nanometers; a sheet of paper is about 100,000 nanometers thick. When the anodization process was applied to aluminum,it created a nanoporous surface called alumina, which proved effective in preventing surrogates of two well known pathogens, Escherichia coli O157:H7 and Listeria monocytogenes, from attaching, according to a study recently published in the journal Biofouling. The study also investigates how the size of the nanopores changes the repulsive forces on bacteria."

Modern metallurgical developments have enabled the scientists to treat metal surfaces by an electrochemical process whereby bacteria find it difficult to adhere there resisting cleaning, washing or various sterilization processes. According to the innovators the nano porous surface created by the anodizing process has electrical charges that repel the microbes when bio-film formation process is attempted by them. Since the surface so created has extremely minute pores, less than 15 microns in size, no food particles can be expected to be trapped inside them to provide any scope for microbes to survive. Though these materials have been tested against only two virulent organisms, viz, E.coli O157 H7 and Listeria monocytogens, there is no reason why it should not be effective against others also. Probably the nanopore size may have to be altered suitably to deal with other pathogens like Salmonella, Shigella and others. Besides application in food industry the new "nanopore" technology may benefit other sectors like medicines, water treatment, shipping industry etc where bacteria poses a challenge.


No comments: