Rapid Detection of E. coli O157:H7 on Turnip Greens Using a Modified Gold Biosensor Combined with Light Microscopic Imaging System

Authors

  • Mi-Kyung Park,

    1. Author Park is with Materials Research and Education Center, Auburn Univ., 275 Wilmore Labs, Auburn, AL 36830, U.S.A. Author Oh is with Dept. of Plant and Food Sciences Sangmyung Univ., 300 Anseo-Dong, Dongnam-Gu, Cheonan, Chungnam, 330–720, South Korea. Direct inquiries to author Oh (E-mail: junhyunoh@smu.ac.kr).
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  • Jun-Hyun Oh

    1. Author Park is with Materials Research and Education Center, Auburn Univ., 275 Wilmore Labs, Auburn, AL 36830, U.S.A. Author Oh is with Dept. of Plant and Food Sciences Sangmyung Univ., 300 Anseo-Dong, Dongnam-Gu, Cheonan, Chungnam, 330–720, South Korea. Direct inquiries to author Oh (E-mail: junhyunoh@smu.ac.kr).
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Abstract

Abstract:  This research aims to demonstrate the feasibility of a modified gold biosensor to detect E. coli O157:H7 in leafy turnip greens. The gold biosensor was modified with dithiobis-succinimidyl propionate (DSP) and/or protein A or G. The gold biosensor modified with DSP (Gold-DSP) was combined with a light microscopic imaging system (LMIS). The optimal concentration and specificity of anti-E. coli O15 polyclonal antibodies (pAbs) on the biosensor were determined. The reliability of Gold-DSP biosensor was investigated by determining the sensitivity, specificity, and limit of detection (LOD) of the Gold-DSP combined with LMIS. The Gold-DSP combined with LMIS was applied to turnip greens for E. coli O157:H7 detection. The modification of Gold biosensor with DSP significantly increased the detected number of E. coli O157:H7. The specificity of pAbs was sufficient to react with target E. coli O157:H7 among the tested bacterial culture. The optimum concentration of pAbs was determined as 200 μg/mL. The sensitivity, specificity, and LOD of Gold-DSP combined with LMIS were determined as 100%, 90%, and 103 CFU/25 mm2, respectively. When applied to turnip greens, the Gold-DSP combined with LMIS could detect 2641 ± 394 and 15383 ± 3853 cell/mm2 with the initial concentrations of 101 and 102 CFU/25 g turnip greens, respectively, after 10 h-enrichment. Overall, this research suggested that the Gold-DSP combined with LMIS could be used to detect E. coli O157:H7 on turnip greens qualitatively and quantitatively.

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