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United States Department of Agriculture

Agricultural Research Service

Research Project: MICROBIAL MODELING AND BIOINFORMATICS FOR FOOD SAFETY AND SECURITY Title: Food Surface Texture Measurement Using Reflective Confocal Laser Scanning Microscopy

Authors
item Sheen, Shiowshuh
item Bao, Guoping
item Cooke, Peter

Submitted to: Journal of Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 27, 2008
Publication Date: July 1, 2008
Citation: Sheen, S., Bao, G., Cooke, P.H. 2008. Food surface texture measurement using reflective confocal laser scanning microscopy. Journal of Food Science and Technology. 73(5):227-234.

Interpretive Summary: The confocal laser scanning microscopy (CLSM) was found useful to demonstrate the surface texture of sliced food surfaces which might be observed smooth by naked-eyes. The microscopy images of sliced ham, salami and cheese showed different degree of surface roughness and may be characterized by two parameters Ra and Rs, where Ra and Rs are the roughness indicators on a line segment and a region of interest bases, respectively. Sandpapers of grit size between 150 and 600 were used to standardize the CLSM instrument hardware settings. Sandpaper particle sizes were further verified by scanning electron microscopy (SEM). The established CLSM instrument settings were utilized to the surface texture study of mechanically sliced food surfaces. Values of the surface roughness of sliced ham, salami and cheese were found in the range of the selected sandpaper surface roughness. The CLSM method may be applied for other surface texture measurements, and to investigate the impact of food surface texture on microbial adhesion or attachment, which might play a significant role of microbial transfer from one surface to another.

Technical Abstract: Confocal laser scanning microscopy (CLSM) was used in the reflection mode to characterize the surface texture (roughness) of sliced food surfaces. Sandpapers of grit size between 150 and 600 were used as the height reference to standardize the CLSM hardware settings. Sandpaper particle sizes were verified by scanning electron microscopy (SEM). The mean amplitude (in micrometer) of surface variation along randomly selected line segments of the scanned sandpaper images showed very close agreement between the measured result and the grit particle size (based on the United States Coated Abrasive Manufactures Institute, CAMI, standard). The established CLSM instrument settings were utilized to study the surface texture of mechanically-sliced food surfaces including cooked ham, salami and cheese. Sliced food surface texture parameters of Ra and Rs were evaluated by this method, where Ra and Rs are the roughness parameters on a line segment and on a region of interest basis, respectively. Values of the surface roughness of sliced ham, salami, and cheese were found to be in the range of the selected sandpaper surface roughness. The CLSM method may be useful for other surface texture measurements, and to investigate the impact of food surface texture on microbial adhesion or attachment, which might play a significant role in microbial transfer from one surface to another.

Last Modified: 11/22/2014
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