Control of Listeria monocytogenes on contact and non-contact surfaces by electrostatic spraying of quaternary ammonia

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Title: Control of Listeria monocytogenes on contact and non-contact surfaces by electrostatic spraying of quaternary ammonia
Author: Dow, Andrea E.
Abstract: The attachment of bacteria on food processing equipment and in the environment can cause potential cross - contamination , which can lead to food spoilage , possible food safety concerns , and surface destruction . Food contact surfaces used for food handling , storage or processing as well as environmental surfaces such as drains , walls , and floors are areas where microbial contamination commonly occurs . Even with proper cleaning and sanitation regimes or practices in place , bacteria can remain attached to the surfaces and this attachment can lead to biofilm formation . The purpose of this research was to determine if electrostatic spraying of quaternary ammonium compounds would provide a more efficient means for sanitizing food contact and environmental surfaces to prevent bacterial attachment and biofilm formation compared to conventional application . The surfaces subjected to 200 ppm of ala -quaternary ammonium treatments were ceramic tile , FRP (plastic wall board ) , polypropylene conveyor belt - mesh top (24 % open mesh ) and stainless steel conveyor – single loop (80 % open mesh ) . To determine the efficacy of the electrostatic sprayer in comparison to pressure spraying for sanitizing , the surfaces were inoculated with a Listeria monocytogenes cocktail with a final concentration of 106 cfu / ml . The test surfaces were analyzed with a swab method prior to inoculation , after 1 hr of attachment and after sanitizing treatment . Overall there were significant (P < 0 .05 ) reductions in the amount of LM that remained on the surfaces after being treated with both the electrostatic spray and the air - pressure spray . There were no significant differences in the bacterial loads between the two treatments (P < 0 .05 ) .To determine electrostatic spray could prevent biofilm formation , surfaces were treated with quaternary ammonium electrostatic spray or a pressure sprayer . The surfaces that were used were ceramic tile , FRP , stainless steel coupons (306 food grade ) , and polyethylene (plastic cutting board ) . After the surfaces were subjected to the treatment , they were allowed to air dry for 30 minutes . The surfaces were then placed in wells containing a Listeria monocytogenes solution with a concentration of 106 cfu / mL . The test surfaces were analyzed after 24 hrs by crystal method analysis and scanning electron microscopy (SEM ) . Results from the crystal method analysis indicated that electrostatic spray significantly (P < 0 .05 ) reduced the biofilm formation on all the surfaces . Overall , electrostatic spray of quaternary ammonium provided a more efficient means of biofilm prevention on multiple food contact and non - contact surfaces .
URI: http : / /hdl .handle .net /2346 /19520
Date: 2008-12

Citation

Control of Listeria monocytogenes on contact and non-contact surfaces by electrostatic spraying of quaternary ammonia. Master's thesis, Texas Tech University. Available electronically from http : / /hdl .handle .net /2346 /19520 .

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