Thursday 4 October 2012

Cotton Antimicrobial Wipes

Dr Brian Condon, a Research Leader at USDA’s Southern Region Research Center provided a review of antimicrobials and their modus operandi before quoting CDC estimates that 76 million people are made sick, 325,000 are hospitalized, and a further 5000 people are dying annually from foodborne diseases.  This costs the nation between $6.5 and $35 billion.  With a significant part of the illness resulting from contamination of food by dirty hands and surfaces it is obvious that disinfected hands and surfaces will be part of the solution.
Bleached cotton antimicrobial wipes don’t release the disinfectant properly  because the fiber is negatively charged and holds onto the positively charged biocide.  A variety of chemical solutions have been researched but now the use of raw cotton for the substrate has given better results.  The pectins and waxes on the raw cotton are clearly affecting the desorbtion of the alkyl dimethyl benzyl ammonium chloride (QUAT).  A series of QUAT absorbtion isotherms using cotton with different levels of pectin and waxes showed that the pectin plays a key role in quat absorbtion.  Varying the chemical properties of the solution by adding electrolytes (common ion effect suppresses QUAT absorbtion), ethanol, and nonionic surfactants also helps.  Cotton is thus rendered usable in antimicrobial wipes where its sustainability, cost competitiveness and better hand confer advantages over the man-made fibers.

(from a paper given at the INDA WOW Conference, Chicago, June 2012)

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