• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.83-92
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• 2009

Individual immunochromatographic assays (ICG) for ochratoxin A (OTA) and zearalenone (ZEA) were optimized and used in the development of a one-step simultaneous immunochromatographic assay (OS-ICG) for the rapid multianalysis of two mycotoxins in corn samples. The nitrocellulose membrane of the OS-ICG was treated with OTA-bovine serum albumin (BSA), ZEA-ovalbumin (OVA), and anti-mouse IgG in the OTA test, ZEA test, and control zones, respectively. Monoclonal antibody-gold conjugates (OTA3 MAb-gold and ZEA2C5 MAb-gold) were sprayed onto the conjugate pad. The visual detection limits were 2.5 and 5 ng/ml for OTA and ZEA, respectively, and the results were obtained within 15 min after starting the analysis. An efficient, simple, and rapid extraction method using 30% MeOH/PBS was established and validated by analyzing the corn samples spiked with OTA/ZEA mixtures (0/0, 5/10, 10/20, and $20/30\;{\mu}g/kg$). The cut-off values of the OS-ICG for the spiked corn were 5 and $10\;{\mu}g/kg$ for OTA and ZEA, respectively. Natural corn samples were analyzed by OS-ICG, direct competitive enzyme-linked immunosorbent assay (DC-ELISA), and HPLC. Results of the OS-ICG were in good agreement with those obtained by DC-ELISA and HPLC. The developed OS-ICG offers a rapid, easy-to-use, and portable analytical system and can be used as a convenient qualitative tool for the on-site simultaneous determination of OTA and ZEA in cereals, food, and agricultural products in one analytical cycle.

• Food Science and Biotechnology
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• v.18 no.3
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• pp.641-648
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• 2009

A one-step simultaneous immunchromatographic (OS-ICG) assay using colloidal gold-monoclonal antibody (gold-MAb) conjugates was developed for the rapid multianalysis of aflatoxin B1 (AFB1) and ochratoxin A (OTA) in feed samples. Visual detection limits for AFB1 and OTA were 0.5 and 2.5 ng/mL, respectively, and the results were obtained within 15 min. Matrix interference from the feed extracts was efficiently reduced by appropriate dilution with buffer. Cut-off values of the OS-ICG assay for the feed spiked with AFB1/OTA mixtures (5/5, 10/10, 25/25, 50/55, 100/100 ${\mu}g/kg$) were 10 and 50 ${\mu}g/kg$ for AFB1 and OTA. The comparative analyses of 65 feed samples by OS-ICG, enzyme-linked immunosorbent assay (ELISA), and high performance liquid chromatography (HPLC) showed good agreement. In this study, we confirmed that simultaneous analysis based on immunoassay is possible and it can be used as an on-site multianalysis of AFB1 and OTA in feed, food, and agricultural products.

• Korean Journal of Veterinary Research
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• v.45 no.2
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• pp.169-177
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• 2005

We developed the one-step strip based on an immunochromatographic (IC) assay for the rapid detection of Listeria spp. Genus-specific monoclonal antibody to flagella of L. monocytogenes was conjugated with 40 nm colloidal gold particles which were prepared in our laboratory. The specificity of the IC strip was tested with pure cultured bacteria. All strains of the genus of Listeria spp. yielded positive reactions and 12 strains of non-Listeria were negative, resulting in a specificity of 100%. L. monocytogenes was artificially inoculated in raw pork macerated with listeria enrichment broth. And then it was 10-fold diluted from $8.7{\times}10^6$ to 8.7 CFU/ml. L. monocytogenes could be detected at a minimum of $8.7{\times}10^5CFU/ml$ before enrichment, $8.7{\times}10^2CFU/ml$ after primary enrichment and 8.7 CFU/ml after secondary enrichment, respectively. These results indicated that the IC strip exhibited high specificity and sensitivity in the detection of Listeria spp.

• Journal of Veterinary Clinics
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• v.31 no.1
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• pp.1-5
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• 2014

Feline leukemia virus (FeLV) is a retrovirus that represents one of the most common and important infectious diseases of cats worldwide and it is responsible for more deaths among cats than any other infectious diseases. Prevalence data are necessary to define prophylactic, management and therapeutic measures for stray, feral and owned cats which are lacking in Bangladesh. The study was carried out to determine the prevalence of FeLV infection in Mymensingh district of Bangladesh using RapiGEN$^{(R)}$ FeLV Ag Test Kit (RapiGEN$^{(R)}$ Inc., Republic of Korea), a rapid one-step immunochromatographic assay. Blood samples from total 130 cats (23 owned cats and 107 unowned cats) were collected and tested following the manufacturer's instruction. An overall prevalence of FeLV infection was 1.54% (2/130). Prevalence was found 1.79% (2/112) on Day 0-up to one year aged cats (young) but no positive case was found in above 1 year (Adult) aged group. In male and female cats, the prevalence was 1.72% (1/58) and 1.39% (1/72), respectively. In un-owned cats the prevalence was 1.87%. Positive cases to FeLV were found only in clinically sick cats. No significant relationship was found according to age, sex, ownership status and health status. To the best of our knowledge this is the first report of the prevalence of FeLV infection in Bangladesh using RapiGEN$^{(R)}$ FeLV test kits which is very much effective because it is easy to apply, less expensive and quick screening of such type of infection.