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Title: Portable hyperspectral fluorescence imaging system for detection of biofilms on stainless steel surfaces

item Jun, Won
item Millner, Patricia
item Sharma, Manan
item Chao, Kuanglin - Kevin Chao
item Kim, Moon

Submitted to: Proceedings of SPIE
Publication Type: Proceedings
Publication Acceptance Date: 4/2/2008
Publication Date: 4/15/2008
Citation: Jun, W., Lee, K., Millner, P.D., Sharma, M., Chao, K., Kim, M.S. 2008. Portable hyperspectral fluorescence imaging system for detection of biofilms on stainless steel surfaces. Proceedings of SPIE, March 17-20, 2008, Orlando, Florida.

Interpretive Summary: A recently developed portable hyperspectral imaging system was used to evaluate detection of biofilms on the surfaces of food processing equipment as a potential indicator for microbial contamination. The detection system is based on hyperspectral line-scan imaging techniques utilizing fluorescence method. Bacterial biofilms were formed on stainless steel coupons in growth medium and evaluated with the portable hyperspectral fluorescence imaging system. Preliminary results showed that fluorescence imaging, using two-band ratio, allowed detection of microbial biofilms on stainless steel coupon surfaces. Presented research is useful to food scientists, engineers, regulatory government agencies (FSIS and FDA), and food processing industries.

Technical Abstract: A rapid nondestructive technology is needed to detect bacterial contamination on the surfaces of food processing equipment to reduce public health risks. A portable hyperspectral fluorescence imaging system was used to evaluate potential detection of microbial biofilm on stainless steel typically used in the manufacture of food processing equipment. Stainless steel coupons were immersed in bacterium cultures, such as E. coli, Pseudomonas pertucinogena, Erwinia chrysanthemi, and Listeria inoocula. Following a 1-week exposure, biofilm formations were assessed using fluorescence imaging. In addition, the effects on biofilm formation from both tryptic soy broth (TSB) and M9 medium with casamino acids (M9C) were examined. TSB grown cells enhance biofilm production compared with M9C-grown cells. Hyperspectral fluorescence images of the biofilm samples, in response to ultraviolet-A (320 to 400 nm) excitation, were acquired from approximately 416 to 700 nm. Visual evaluation of individual images at emission peak wavelengths in the blue revealed the most contrast between biofilms and stainless steel coupons. Two-band ratios compared with the single-band images increased the contrast between the biofilm forming area and stainless steel coupon surfaces. The 444/588 nm ratio images exhibited the greatest contrast between the biofilm formations and stainless coupon surfaces.