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Title: COMPARISON OF SCANNING ELECTRON AND ATOMIC FORCE MICROSCOPY OF SURFACE FINISHES ON STAINELESS STEEL THAT REDUCE BACTERIAL ATTACHMENT

Author
item Arnold, Judy
item BAILEY, G - EPA

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 3/29/2000
Publication Date: 5/12/2000
Citation: ARNOLD, J.W., BAILEY, G.W. COMPARISON OF SCANNING ELECTRON AND ATOMIC FORCE MICROSCOPY OF SURFACE FINISHES ON STAINELESS STEEL THAT REDUCE BACTERIAL ATTACHMENT. MEETING ABSTRACT. 2000.

Interpretive Summary: Proceedings of the Journal of Scanning Microscopies (2000)

Technical Abstract: Using materials for food processing surfaces that are resistant to bacterial contamination could enhance food safety. Two methods of microscopy were partnered to correlate form and function of surface finishes. Relative differences in the morphology of surface finishes were measured by atomic force microscopy (AFM) and compared with changes in bacterial attachment and early biofilm formation by scanning electron microscopy (SEM). Aliquots (1- ml) of meat rinses were incubated in trypticase soy broth 18 hr, 37C. Then the culture was diluted in broth to Absorbance (410nm) of .3 as measured by spectrophotometry. Stainless steel disks (1-cm diameter) were added, and the cultures were grown to .6, 37C. The disks were removed from the bacterial suspensions and processed for SEM. Bacteria readily attached to the untreated surface. The sandblasting pitted the surface, and with SEM the pit-marks seen by visual observation appeared as "craters" to which bacteria attached even more frequently. The steel-ball burnished surface was much smoother, but was not the least resistant to bacteria. Stainless steel that had been electropolished showed significantly fewer bacterial cells than the other treated surfaces. For AFM disks were removed from the bacterial suspensions and examined directly. Dimensions were calculated from the images for surface roughness, bearing ratio, center line average, etc. Changes in the AFM parameters had the same relative differences as the data from the bacterial counts for the SEM studies, with the electropolished finish showing the most reduced roughness parameters. These data demonstrate that AFM can predict the potential for bacteria to attach and form biofilms on surfaces.