Salt, as food, is the most essential element for human survival due to its significant physiological functions. Here, we report the simultaneous detection of Pb and Cd in sea salt by square wave anodic stripping voltammetry (SWASV). Stripping voltammetric measurements were conducted using a manufactured rotating disk electrode system (MRDES). The detection limit was 3.6±0.18 μgL−1 for Pb and 3.9±0.37 μgL−1 Cd in NaCl solution. When the pH increased from 5.5 to 8.5, the peak currents of Pb and Cd decreased. At a pH of 8.3, the ratio of the current drop compared with that at a pH of 5.5 was 0.6 for Pb and 0.73 for Cd. The concentrations corrected by the current drop are in agreement with the concentrations obtained with ICP (inductively coupled plasma). This system demonstrates the reliable detection of heavy metals in aqueous media and, at a high Na + concentration, the successful application for the determination of Pb and Cd in sea salts.

Salt, as food, is the most essential element for human survival due to its significant physiological functions. Here, we report the simultaneous detection of Pb and Cd in sea salt by square wave anodic stripping voltammetry (SWASV). Stripping voltammetric measurements were conducted using a manufactured rotating disk electrode system (MRDES). The detection limit was 3.6±0.18 µgL− 1 for Pb and 3.9±0.37 µgL− 1 Cd in NaCl solution. When the pH increased from 5.5 to 8.5, the peak currents of Pb and Cd decreased. At a pH of 8.3, the ratio of the current drop compared with that at a pH of 5.5 was 0.6 for Pb and 0.73 for Cd. The concentrations corrected by the current drop are in agreement with the concentrations obtained with ICP (inductively coupled plasma). This system demonstrates the reliable detection of heavy metals in aqueous media and, at a high Na + concentration, the successful application for the determination of Pb and Cd in sea salts.

황색포도상구균 식중독은 해당 균이 세포 밖으로 분비 하는 장독소에 의해 발병되며, 지금까지 밝혀진 16가지 독소 중 내열성이 가장 강하고 흡입중독으로 쉽게 질환을 일으킬 수 있는 Staphylococcal enterotoxin B형을 분리해 내는 방법에 대해 연구하였다. 분자량 26-29 kDa의 단순 단백질인 SEB를 분리 및 정제하기 위한 방법으로 fast protein liquid chromatography (FPLC)를 이용하였으며, 정제율을 높이기 위해 ion exchange chromatography와 gel filtration chromatography의 두 과정을 거쳤다. 실험 결과 SEB의 분리 조건은 CIEX에서 WorkBeads 40S컬럼 의 분리능이 가장 좋았고, 염 농도 15%에서 SEB가 분리 됨을 확인하였다. CIEX에서 획득한 분획으로 단백질을 크기별로 나누는 GF를 실시하였을 때, Sephacryl S-100 컬럼을 사용하여 정제된 SEB를 획득할 수 있었다. 시료 가 컬럼을 통과할 때 염 농도가 효율적으로 조절될 수 있 도록 하고 SEB를 농축하려 시도한 투석 및 완충액 치환 방법은 전체적인 단백질량 손실을 가져오는 것으로 나타 났다. 본 연구에서 개발된 독소 분리 및 정제 방법은 향 후 다른 장독소 분리에도 활용할 수 있으며, 식중독 신속 진단법 개발 및 항체 생산 발전에 효율을 높일 수 있을 것으로 기대된다.

Melamine has been reported to be responsible for kidney stones and renal failure among infants and children. Con-ventional detection methods, High-Performance Liquid Chromatography (HPLC) and Gas Chromatography (GC), aresensitive enough to detect trace amounts of the contaminant, but they are time consuming, expensive, and labor-intensive. Hyperspectral imaging methods, which combine spectroscopy and imaging, can provide rapid and non-destructive means to assess the quality and safety of agricultural products. In this study, near-infrared hyperspectralreflectance imaging combined with partial least square regression analysis was used to predict melamine particleconcentration in dry milk powder. Melamine particles, with concentration levels ranging from 0.02% to 1% byweight ratio (g/g), were mixed with dry milk powder and used for the experiment. Hyperspectral reflectance imagesin the wavelength range from 992.0nm to 1682.1nm were acquired for the mixtures. Then PLSR models weredeveloped with several preprocessing methods. Optimal wavelength bands were selected from 1454.5nm to 1555.6nm using beta-coefficients from the PLSR model. The best PLSR result for predicting melamine concentration inmilk powder was obtained using a 1st order derivative pretreatment with Rv=0.974, SEP=±0.055%, and F=6.

The aim of this study is to develop the one dot rapid detection kit that meets the limit of detection (LOD) of KFDA (10 μg/kg) for Aflatoxin B1 (AFB1). The fabrication process of the one dot rapid detection kit, such as gold nanoparticle and AFB1-BSA conjugation, and AFB1-polyclonal antibody concentration was optimized. Fabricated rapid detection kits were tested with the standard AFB1 solutions and the solutions extracted from contaminated maize samples. The LOD in the standard AFB1 solution and extracted AFB1 solution was 5 μg/kg for both. This result is lower than the LOD of KFDA in food (10 μg/kg) and satisfies the LOD of EU (2-12 μg/kg) and Japan (10 μg/kg) in food.

In this study, a rapid immuno-chromatographic assay was developed to detect Salmonella Typhimurium. This assay was based on the lateral flow immunoassay. Two different anti-Salmonella polyclonal antibody (Pab) are used in this strip assay for the double antibody sandwich immunoassay method. The strip sensor was composed of sample pad, conjugation pad, membrane, and absorbent pad. For the optimal conjugation between nano-gold and anti-Salmonella Pab, the pH value of colloidal gold solution was determined to 8.4. To prevent non-specific binding between nano gold and anti-Salmonella Pab, sample pad and membrane was treated with PBS buffer, included 2% BSA and 10% sucrose. The control and detection zones were visually detected according to antigen-antibody binding. The detection limit of the developed strip assay was 105 CFU/mL within 10 min, and improved until 104 CFU/mL after 12 hr.

This study was performed to develop and optimize a rapid strip kit for the dual-detection of Aflatoxin B1 (AF) and Ochratoxin A (OTA). The strip kit is composed of sample pad, conjugation pad, nitrocellulose membrane, and absorbent pad. Manually spotted mycotoxin-BSA conjugates and anti-mouse IgG on nitrocellulose membrane were used as the test line and the control line, respectively. Conditions for rapid and easy detection of mycotoxins, conjugation between toxin-MAbs and nano Au particles, pretreatment method of pads, and composition of standards solutions were optimized. Feasibility of the strip kit to detect AF and OTA were evaluated with standard samples. Test results were acquired in 10 min and the detection limits were 100 ppm for AF and OTA, respectively.