Cronobacter muytjensii는 유아용 조제분유(IFP)의 잠재적 위험요인으로 중요한 식품 기인성 병원균이다. 이 연구에 서는 C. muytjensii 검지를 위한 특이적 면역글로불린 G(IgG)를 개발하고, 이 anti-C. muytjensii IgG를 이용하여 간접 비경쟁 효소면역측정법(INC-ELISA)을 개발하였다. 그 결과, 새롭게 개발한 INC-ELISA 방법은 C. muytjensii에 매우 민감하고, 순수배양 시 6.5×103 CFU/㎖의 검출한계와 유아용 조제분유에서 1 cell/25 g의 검출한계를 나타내었다. INC-ELISA 방법은 또한 C. muytjensii에 탁월한 특이성을 보이고, Cronobacter 속 외 11종의 다른 식품 기인성 병원균 계통과의 교차반응을 보이지 않았다. 이러한 결과는, 개발된 INC-ELISA 방법이 C. muytjensii에 매우 민감하고 효율적 이며, 신속하고 용이한 검출을 위한 진단 키트 개발에 적용할 수 있음을 시사한다.

Substantial efforts have been made to manipulate ruminal environment in a hope to enhance ruminal fermentation efficiency for better ruminant productivity. Some of examples are methane inhibitors, antibiotics, microbial enzymes, fatty acids and/or lipid feeding, buffering agents, ionophores and probiotics. Of these efforts, the non-ionic surfactant (NIS) has been known for its stimulation to release enzymes from a range of anaerobic microbes. A series of studies were conducted 1) to evaluate NIS diluted with water and ethanol on in vitro ruminal fermentation and 2) to determine the influence of diluted NIS on digestibility of feedstuffs. In first experiment (Exp. 1), NIS was diluted with water or ethanol to measure its effects on in vitro microbial growth, ruminal enzyme activities and gas production by mixed ruminal microbial culture. The NIS was diluted with water or ethanol separately in a 1:5 ratio (w/v). Water and ethanol-diluted NIS with wheat flour were added with rice straw-based mixed ruminal microbial cultures at the rate of 2 ㎎ NIS/16 ㎖ McDougall buffer plus 4 ml ruminal fluid solution. The mixed ruminal microbial culture was run without any NIS addition as control. Addition of NIS either diluted with water or ethanol has significantly reduced the gas production in mixed ruminal microbial culture at 12 and 24 h of incubation. At 48 h post incubation, gas production was the highest with the addition of ethanol diluted NIS followed by water-diluted NIS and control. Carboxy methyl cellulase activity in rice straw-based mixed ruminal bacterial culture was significantly higher with the addition of ethanol-diluted NIS compared with the addition of water-diluted NIS and control at 24 and 72 h post incubation. In second in vitro experiment (Exp. 2), effects of addition of ethanol diluted NIS on dry matter (DM) digestibility of alfalfa hay, gas production, pH and cellular growth in mixed ruminal microbial culture were examined. Alfalfa hay based mixed ruminal microbial culture without any NIS addition was run as a control. The pH of mixed ruminal microbial culture was significantly lower than control at all post incubation sampling hours. In vitro DM digestibility of alfalfa hay was significantly higher with the addition of NIS compared with control. Gas production was significantly less with NIS addition compared with control at all post incubation sampling hours. Microbial growth in mixed ruminal microbial culture was significantly increased with the addition of NIS compared to control.

In this paper, the electrochemical non-enzyme immunosensor has been developed for the determination of salmonella antigen, using inverse voltammetry. For the estimation of salmonella antigen concentration, the nanoparticles synthesized by microemulsion method were conjugated with salmonella antigen. Then, the immunocomplex between antibody immobilized on the transducer surface and antigen containing a magnetic nanoparticles was formed. From the linear relationship between the reduction peak current of Fe(III) and salmonella antigen concentration, it is suggested that the electrochemical non-enzyme biosensor is applicable to detect salmonella antigen in the concentration range of