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Title: EFFECTS OF CORROSIVE TREATMENT ON STAINLESS STEEL SURFACE FINISHES AND BACTERIAL ATTACHMENT

Author
item Arnold, Judy
item SUZUKI, OSAMU - JGC CORPORATION,JAPAN

Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/22/2003
Publication Date: 12/1/2003
Citation: Arnold, J.W., Suzuki, O. 2003. Effects of corrosive treatment on stainless steel surface finishes and bacterial attachment. Transactions of the American Society of Agricultral Engineers. 46(6):1595-1602.

Interpretive Summary: Corrosion, an important factor for the durability of a metal finish after exposure to water and chemicals during processing, is a real concern for many wet process industries. The effects of rouging, corrosion, and biofouling are costly problems on the surface of stainless steel, the most common material in processing plants. We have developed a treatment similar to wet-processing conditions commonly used in food processing to test the effects of corrosive treatment on bacterial attachment. Samples from an original set of surface finishes were compared with controls to determine the variation in bacterial attachment for each finish. A duplicate set of samples was exposed to the corrosive treatment to simulate processing conditions. All samples were examined by visually and with various methods of microscopy for surface characteristics and elemental composition. Bacterial growth and attachment were measured for each surface finish and compared with controls and 7 other finishes. Exposure to the model processing conditions resulted in changes in the numbers of bacteria that attached to the surfaces. Bacterial attachment to stainless steel was determined by the characteristics of the surface finish. After exposure, more bacteria attached to the steel-ball burnished and glass-beaded finishes than to the original finishes. However, the control finish and the electropolished had fewer bacteria attach after exposure than the original samples. Electropolished samples were most resistant, before and after exposure to corrosive treatment, than the seven other finishes tested. The data presented in this paper will serve as a useful reference for all the surface finishes, allowing manufacturers and processors to compare and select the most appropriate finish for specific locations and functions.

Technical Abstract: Corrosion, an important factor for the durability of a metal finish after exposure to water and chemicals during processing, is a real concern for many wet process industries. The effects of rouging, corrosion, and biofouling are costly problems on the surface of stainless steel, the most common material in processing plants. We have developed a treatment that is indicative of wet-processing conditions commonly used in food processing, pharmaceutical, and bioprocess applications to test the effects of corrosive treatment on bacterial attachment. Samples from an original set of surface finishes were compared with mill finish controls to determine the variation in bacterial attachment for each finish. A duplicate set of samples was exposed to the corrosive treatment to simulate processing conditions. All samples were examined by visual inspection and electron probe microanalysis for surface characteristics and elemental composition, respectively; and bacterial growth and attachment were measured by spectrophotometry and scanning electron microscopy. Bacterial attachment for each surface finish was measured and compared with controls and 7 other finishes. Exposure to the model processing conditions resulted in changes in the numbers of bacteria that attached to the surfaces. Bacterial attachment to stainless steel was determined by the characteristics of the surface finish. After exposure, significantly greater numbers of bacteria attached to the steel-ball burnished and glass-beaded finishes than to the original finishes. However, the control mill finish and the electropolished had fewer bacteria attach after exposure than the original samples. Electropolished samples were significantly most resistant, before and after exposure to corrosive treatment, than the seven other finishes tested. The data presented in this paper will serve as a useful reference for parameters of all the surface finishes, allowing manufacturers and processors to compare and select the most appropriate finish for specific locations and functions.