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United States Department of Agriculture

Agricultural Research Service

Title: MULTIPLE IMAGING TECHNIQUES DEMONSTRATE THE MANIPULATION OF SURFACES TO REDUCE BACTERIAL CONTAMINATION AND CORROSION

Authors
item Arnold, Judy
item Boothe, Dorothy
item Suzuki, O - JGC CORP, JAPAN
item Bailey, G - EPA, ATHENS, GA

Submitted to: Journal of Microscopy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2004
Publication Date: December 1, 2004
Citation: Arnold, J.W., Boothe, D.D., Suzuki, O., Bailey, G.W. 2004. Multiple imaging techniques demonstrate the manipulation of surfaces to reduce bacterial contamination and corrosion. Journal of Microscopy. 216:215-221.

Interpretive Summary: Microscopy techniques are combined to determine how to finish stainless steel surfaces for food processing applications. Stainless steel surfaces were engineered to reduce bacteria and corrosion during product processing. The microscopy methods, scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and atomic force microscopy (AFM) complemented each other to give better test results. Samples were examined visually and EPMA to study surface characteristics without bacteria. Then stainless steel disks (1-cm diameter) were added to bacterial cultures, and the cultures were grown to sufficiently cover the test surfaces. Disks for each surface finish analyzed separately by AFM were cut from the same sheets used for SEM. Relative differences in the surfaces of the stainless steel finishes, including Z ranges, roughness, and other measurements corresponded by treatment with the differences in reduction of bacterial counts shown by SEM. A model of wet-processing conditions tested the effects of corrosive treatment of surfaces on bacterial attachment. The chemical processes of corrosive treatment on surfaces affected bacterial attachment. The surface resistance achieved by electropolishing reduced bacterial numbers and corrosion. Thus, the multiple imaging techniques showed that engineered changes in stainless steel surfaces improved the resistance of the surface finish to bacterial attachment, biofilm formation, and corrosion.

Technical Abstract: Surface imaging techniques are combined to determine appropriate manipulation of technologically important surfaces for commercial applications. Stainless steel surfaces were engineered to reduce bacterial contamination, biofilm formation, and corrosion during product processing. The complementarity of microscopy methods, scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and atomic force microscopy (AFM) assessed and correlated form and function of surface modifications. Samples were examined by visual inspection and EPMA for surface characteristics and elemental composition, respectively. Aliquots of bacterial suspensions were diluted in broth and measured by spectrophotometry. Stainless steel disks (1-cm diameter) were added, and the cultures were grown to sufficient density to form monolayers of bacterial cells on test surfaces. Disks for each surface finish analyzed separately by AFM were cut from the same sheets used for SEM. Relative differences in the surface morphology of the stainless steel finishes, including Z ranges, roughness, and other measurements corresponded by treatment with the differences in reduction of bacterial counts shown by SEM. A model of wet-processing conditions tested the effects of corrosive treatment of surfaces on bacterial attachment. The chemical processes of corrosive treatment on surfaces affected bacterial attachment. The surface resistance achieved by electropolishing significantly reduced bacterial numbers and corrosion from controls. Thus, the multiple imaging techniques showed that engineered changes in stainless steel surfaces improved the resistance of the surface finish to bacterial attachment, biofilm formation, and corrosion.

Last Modified: 10/1/2014
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