The potential application of surface-enhanced Raman spectroscopy (SERS) was investigated to detect Salmonella Typhimurium and Escherichia coli. The silver colloidal suspension with optimum optical characteristics was obtained for SERS detection. The SERS spectra were collected the wavelengths from 500 to 1200 cm-1. The characteristic SERS spectra were obtained from both S. Typhimurium and E. coli; however the observed SERS peak profiles for both pathogens exhibited similar peak profiles. Therefore, the results suggest that even though SERS possesses the potential capability to detect pathogens rapidly, further study is required to resolve the ambiguous spectra profiles for S. Typhimurium and E. coli.

Continuous outbreaks of Shigella spp. have raised concerns about the lack of rapid and on-site applicable biosensor method for Shigella detection. Since a bacteriophage has recently been employed as an emerging bio-recognition element in biosensor method, Shigella sonnei-specific bacteriophage was isolated and purified from a slaughterhouse with the final concentration of 2.0×1012 PFU/mL in this study. Analysis of purified S. sonnei-specific bacteriophage using transmission electron microscopy indicated that it possessed an icosahedral head with a relatively long non-contractile tail. It was therefore classified as a member of the Siphoviridae family. Head width, head length, and tail length were 69.9±11.2 nm, 77.5±8.8 nm, and 264.4±33.9 nm, respectively. The genomic DNA size of the S. sonnei-specific bacteriophage was determined to be approximately 25 kb by using 0.4% agarose gel electrophoresis. In specificity test with 43 food-associated microorganisms, the S. sonnei-specific bacteriophage exhibited a clear plaque against S. sonnei only. In addition, the S. sonnei-specific bacteriophage was stable within a wide range of pH values (pH 3-11) and temperatures (4-37 ). Thus, the present study demonstrated the excellent specificity and stability of the S. sonnei-specific bacteriophage as a novel bio-recognition element for S. sonnei detection in foods.

살모넬라는 주요한 식중독균의 하나로 미생물학적 식품 품질을 보증하기 위해 신속·정확하게 현장에서 관리되고 모니터링되어야 한다. 본 연구팀에서는 광학 현미경 기반의 이미징 시스템과 바이오센서가 결합된 모니터링 시스템을 개발하였고, 이를 살모넬라에 적용하기 위해서는 바이오센서에 적용되는 생물학적 수용체의 개발이 절대적으로 필요한 실정이다. 따라서 본 연구에서는 살모넬라에 반응 하는 특이적인 anti-Salmonella 다중클론 항체를 토끼로부터 성공적으로 생산·정제하였으며, 최종 항체의 농도는 2 mg/mL로 결정되었다. 또한, 정제된 anti-Salmonella 다중클 론 항체의 역가가 상업용 anti-Salmonella 다중클론 항체보다 전 항체 농도 범위에서 우수함을 알 수 있었다. 정제된 항체 특이성 검토를 위해, 정제된 anti-Salmonella 다중클론 항체를 20 종의 살모넬라 serotypes과 20 종의 non-Salmonella strains과 반응시킨 결과, 20 종의 non-Salmonella strains과는 특이성을 보여주지 않은 반면 19 종의 살모넬라 serotypes와 유의적으로 높은 반응성으로 보여 주었다. 최종적으로, anti-Salmonella 다중클론 항체가 고정화된 골드 센서를 살모넬라 현탁액에 노출시켰을 때, 수 백여 개의 살모넬라가 센서 표면에 capture되어 있음을 확인할 수 있었다. 따라서, 본 연구를 통해 생산·정제된 anti-Salmonella 다중클론 항체는 새로운 생물학적 수용체로서 충분한 역가와 특이성 그리고 센서에 적용 시 살모넬라와의 높은 결합력을 보여주었으므로 광학현미경 기반 이미징 시스템을 활용한 바이오센서 모니터링 시스템에 새로운 생물학적 수용체로 적용될 수 있으리라 판단된다.

This purpose of this study was to determine the best enrichment medium for rejuvenating and recovering Salmonella placed in cold temperature prior to the employment of the gold biosensor combined with a light microscopic imaging system. A mixture of nalidixic-resistant Salmonella Typhimurium and Enteritidis were inoculated onto chicken (1,000 CFU/chicken). After cold injury at 4℃ for 24 hr, Salmonella on chicken was enriched for 6 hr with six non-selective media including buffered peptone water broth, lactose broth, brain heart infusion broth (BHI), universal pre-enrichment broth, nutrient broth, and tryptic soy broth, and five selective media including brilliant green broth (BG), rappaport-vassiliadis R10 broth, selenite cystine broth, selenite broth, and tetrathionate brilliant green broth (TBG) for the comparison of Salmonella growth. Various concentrations of Salmonella (10, 50, 100, 500, and 1,000 CFU/chicken) were then enriched for 6 hr in both BHI and BG media to select the best media. BHI was selected as the most effective non-selective enrichment medium, while BG was selected as the most effective selective enrichment medium. Finally, BHI medium was selected as the most efficient enrichment medium for Salmonella growth injured from cold temperature during processing or storage.

This study investigated the effect of electron beam (EB) treatment on the microbial reduction of dried laver (Porphyra tenera) and identified EB-resistant bacteria from the treated dried laver. After EB treatments of 4 kGy and 7 kGy, the numbers of total bacteria and EB-resistant bacteria were measured using tryptic soy agar and mannitol salt agar, respectively. The morphological and biochemical characteristics of each isolated EB-resistant bacteria were investigated and these bacteria were identified. Compared to the control (1.5±0.2)×106 CFU/g, the total bacterial number was significantly decreased to (5.4±0.5)×104 CFU/g and (1.1±0.6)×104 CFU/g after EB treatments of 4 kGy and 7 kGy, respectively. With a higher EB dosage, the number of red colonies was almost same, whereas the number of yellow colonies was significantly decreased to (3.3±1.2)×103 CFU/g and 0 CFU/g for 4 kGy and 7 kGy, respectively. All red and yellow colonies were gram-positive cocci, catalase-positive, and resistant to 3% and 5% NaCl media. From the 16S rDNA sequence analysis, yellow and red colonies were identified as either Micrococcus flavus or M. luteus, with 99% similarity for the yellow colonies, and Deinococcus proteolyticus and D. piscis, with 99% and 97% similarity for the red colonies, respectively.

본 논문은 미국 남부지역 특화작물인 머스커다인 포도의 부분별 추출물의 항산화능 및 항균활성을 구명하기 위한 목적으로, Higgins, Jumbo, Noble 3종의 머스커다인 품종을 대상으로 하여 포도의 과피/과육부분과 종자부분을 추출하 여 실험에 사용하였다. 각 추출물에 대하여, 항산화능은 총페놀함량 및 라디칼 소거능(Scavenging activity 및 EC50) 을, 항균활성은 E.coli K12에 대한 최소생육저해농도 (minimum inhibitory concentration, MIC)를 조사하였다. 종 자 추출물의 총페놀함량은 231.24~294.81 mg/mL GAE로 과피/과육 추출물에 비하여 높은 함량을 보였다. 또한 Higgins품종의 종자 추출물이 가장 우수한 라디칼소거능 (EC50=0.026 mg/mL)을 나타내, 종자추출물이 과피/과육추 출물보다 우수한 항산화능을 보유하였다. 반면, E.coli K12 에 대한 항균활성은 Higgins 품종의 과피/과육추출물이 40 mg/mL의 MIC를 보임으로써 가장 우수하였다. 따라서, 본 연구는 머스커다인 포도 추출물이 천연 유래의 항산화 및 항균 기능성을 보유한 소재로 활용될 수 있는 잠재적 가치 를 제시하였다.