• Journal of Food Hygiene and Safety
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• v.33 no.3
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• pp.185-192
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• 2018

The purpose of this study was to develop an indirect enzyme-linked immunosorbent assay (indirect ELISA) based on a monoclonal antibody (MAb) that is specific to mackerel thermal stable-soluble protein (TSSP), that can be used for the rapid detection of mackerel in processed marine foods. Among the four MAbs (3A5-1, 2, 9, and 12) developed in previous studies, the 3A5-2 MAb that showed high specificity and sensitivity were selected and used to develop the indirect ELISA method. The detection range of the indirect ELISA was 0.02%-0.001% and the detection limit of 0.001% was shown. No cross-reaction to other marine products and food ingredients was observed by the indirect ELISA. Processed marine foods containing mackerel with ${\geq}0.3$ O.D. value at 405 nm were estimated as positive samples by the indirect ELISA. Therefore, the indirect ELISA can be used as a rapid and sensitive method to identify mackerel authenticity and adulteration in processed marine foods.

• Korean Journal of Veterinary Research
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• v.43 no.1
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• pp.129-137
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• 2003

Porcine reproductive and respiratory syndrome (PRRS) is characterized by reproductive failures in sows and respiratory problems in piglets. The nucleocapsid(N) protein, encoded by the open reading frame 7 (ORF7) gene, is known to be the most abundant and antigenic protein in PRRS virus. Therefore, it was suggested that the N protein could be a suitable candidate for the detection of PRRS virus-specific antibodies and diagnosis of PRRS. In the present study, the ORF7 gene encoding the N protein was cloned and expressed as a fusion protein with the glutathione S-transferase (GST) in Escherichia coli. The resulting GST-N recombinant protein was used as an antigen for an indirect sandwich enzyme-linked immunosorbent assay (i-ELISA). Expressed GST-N recombinant protein was migrated at 41 kDa and reacted with ORF7-specific monoclonal antibody by Western blotting. In order to increase the specificity of the ELISA for the detection of PRRS virus-specific antibodes, an i-ELISA was developed using an anti-GST antibody as a capture antibody. The sensitivity and specificity of developed i-ELISA were 92% and 96%, respectively. Based on these results, it was suggested that the i-ELISA is a simple and rapid test for screening a large number of swine sera for the anti-PRRS virus antibodies.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.567-575
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• 1989

This study was conducted to evaluate the possibility of application of a microenzyme-linked immunosorbent assay(micro-ELISA) for the serodiagnosis of specific toxoplasma antibodies in swine sera and this test was performed as a microplate system by coating the polystyrene plates with toxoplasma soluble antigen, incubated serially diluted sera, then added horse radish peroxidase labelled goat anti-swine IgG(r) conjugate followed by o-phenylenediamine as substrate. The color development by enzyme-substrate reaction was determined by the photometric reading [ELISA reader at 490nm (OD)] and visual reading. The soluble antigen was prepared from the tachyzoites in mouse peritoneal cavity. A total of 1,200 swine sera from pig slaughter-house and a total of 116 swine sera from pig breeding station (S-C farm) were tested for the detection of antibodies to Toxoplasma gondii. The results obtained were summarized as follows: 1. The optimal reactions of indirect ELISA for the test sera were determined by the dilution of antigen 1:256 and 1:3,200 of horse radish peroxidase conjugate [anti-swine IgG(r)]. 2. The specific togoplasma antibody(IgG) in pigs infected with Tp artificially were detected as the serum titers of 1:64 or 1:128 at one week postinfection. 3. Of a total of 1,200 swine sera from pig slaughter-house 505 samples of sera were detected as positive (42.1%) and of a total of 116 swine sera from S-C pig breeding station 68 samples of sera as positive (58.6%). 4. The specific antibody(IgG) detection rates against a total of 1,200 test sera from pig slaughter-house were not significant between male (43.1%) and female (40.7%). 5. The indirect ELISA was proved to be a sensitive and specific procedure for the serodiagnosis of swine toxoplasmosis and also evaluated as an effective screening test for the large scale of test samples in laboratory.

• The Korean Journal of Food And Nutrition
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• v.26 no.4
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• pp.936-944
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• 2013

Cronobacter muytjensii is an important foodborne pathogen as a potential risk in infant formula powder (IFP). To develop a new and sensitive method for the detection of Cronobacter spp. in IFP, an immunoglobulin G (IgG) specific for C. muytjensii (formerly known as Enterobacter sakazakii ATCC 51329) was developed. Further, an indirect noncompetitive enzyme-linked immunosorbent assay (INC-ELISA) was developed by using the anti-C. muytjensii IgG. As a result, this newly developed INC-ELISA method was found very sensitive for C. muytjensii with detection limit of $6.5{\times}10^3CFU/ml$ in pure culture and 1 cell/25 g of IFP. This INC-ELISA method also displayed excellent specificity for C. muytjensii showing no cross-reactivity with other strains of Cronobacter genus and 11 other foodborne pathogenic strains. These results show that the developed INC-ELISA method was very sensitive, efficient, and rapid for the detection of C. muytjensii. Hence, this method could be applied to the development of diagnostic kits for the rapid and easy detection of C. muytjensii.

• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.81-85
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• 2000

Coxiella burnetii (C burnetii) is the causative agent of Q fever in animal and human. The distribution of the disease has been documented around world. In this study we developed the competitive enzyme linked immunosorbent assay(cELISA) and compared it with indirect immunofluorescent assay(IFA). A monoclonal antibody(Mab) against C burnetii and a peroxidase-conjugated anti-mouse IgM were used as an indicator system competing against antibody in animal serum or as an indicater of the absence of antibody. Sera were considered antibody positive when the percentage inhibition index(PI index) is upper than 30. PI index is calculated as 100-[sample OD/Mab OD)${\times}100$]. Among 162 bovine serum samples, 23 samples were antibody positive both in cELISA and IFA. And 156 samples showed same results. From goat with experimentally induced infection with C burnetii the antibody was detected 20 days early in cELISA compared to IFA. On the basis of present findings, it was demonstrated that cELISA is a reliable diagnostic method for The detection of specific antibodies against C burnetii infection.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.991-996
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• 2000

Enzyme-linked immunosorbent assay was developed for the analysis of soy protein in foods. Competitive indirect ELISA (ciELISA) was established by using specific antibodies against the heat-stable acidic subunits (AS) of glycinin. Soy proteins in each sample used in this study were solublized in the presence of urea and DTT and boiled at $100^{\circ}C$ for 1hr and then were renatured with a cystine-containing solution. After these treatments, each isolated soy protein (ISP) heated at 60, 70, 80, $90^{\circ}C$ for 10 minutes showed almost the same curve as unheated one in the ciELISA. The detection limit of ISP was 0.3 ${\mu}g/mL$. Anti-AS antibodies have very low reactivities less than 0.1% toward non-meat proteins such as skim milk and casein and did not show any reactivities toward egg white powder and ovalbumin. When laboratory-made sausages containing ISP of $0.5{\sim}3%$ were assayed by ciELISA, the mean recovery was about 83% (C.V., 19%). In addition, the average content of soy protein in commercial sausages was 1.27%.

• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.601-609
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• 2000

An enzyme linked immunosorbent assay (ELISA) was developed to screen residues of sulfadimethoxine (SDM) in edible animal products. An indirect competitive ELISA was allowed to compete with rabbit anti-SDM for binding to a limited amount of SDM-gelatin conjugate and SDM in serum samples. Sera was diluted 20 times with phosphate buffered saline (PBS) and boiled for 5 minutes to destruct immunoglobulins of serum. Detection limit of this competitive ELISA for SDM was 0.1 ppb or less. Among eight sulfonamide analogues tested for specifity, only sulfamonomethoxine showed significant cross-reaction in the assay. The EC-50 value for sulfamonomethoxine was 3.5 ppm. Recovery of SDM in spiked serum samples between 100 ppb and 500 ppb ranged from 110.7% to 128.9%.

• Journal of Food Hygiene and Safety
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• v.10 no.4
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• pp.213-217
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• 1995

A screening method has been developed for detecting sulfamethazine(SMZ) contamination of meat or feeds by using horseradish peroxidase (HRP) labeled protein A (Prot AHRP)and an indirect competitve enzyme-linked immunosorbent assay(ELISA). The assay is based on competitve binding of guinea pig anti-SMZ with SMZ in smaple and SMZ-gelatin conjugate(SMZ.GEL). Percent binding (B.Bo$\times$100) was calculated from the absorbance in the absence (B0) and presence (B) of SMZ. By the sandard curve prepared by plotting log(SMZ) vs percent binding of each known reference solution, the detection limit was 1.0ppb or less. Cross reacton with sulfadimethoxine, sulfaguaniding, sulfamerazine, sulfamthoxpyridazine, sulfanilamide, sulfisomidine and sufisoxazole were not observed. But sulfamerazine crossreacted in the test. The EC-50 value (concentration causing 50% inhibition of color development compared with blank) of sulfamerazine was 2.0 ppm. Further quality control will make the ELISA system ideal for the detection of SMZ in meat or feeds.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.720-725
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• 2000

To reduce the antigenicity of egg white (EW), EW was treated with several proteolytic enzymes, trifluoromethanesulfonic acid (TFMS), heat, and NaOH. Competitive indirect enzyme-linked immunosorbent assay (ciELISA), using rabbit anti-EW antibody, was performed to examine the antigenicity of the treated EW's. Enzymatic hydrolysis gave no good effect on the reduction of the antigenicity of EW. Neither did the pretreatment with ${\gamma}-irradiation$ before the hydrolysis reduce the antigenicity. TFMS treatment removed the antigenicity of EW. The antigenicity of EW heated at $120^{\circ}C$ for 30 min or treated with NaOH at 0.3% (w/v) and more, decreased to less than 1/10,000 as compared with that of native EW. The combinatory treatment with NaOH, followed by heat at $70^{\circ}C$ for 15 min had a synergic effect on the reduction of the antigenicity of EW.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1221-1226
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• 2000

Specific antibodies were produced to develope the enzyme-linked immunosorbent assay for analysis of soy proteins and the properties of the antibodies were compared. Isolate soy protein(ISP), and ISP heated with SDS and urea (ISP(SU)), acidic subunits(AS) of 11S globulin were immunized to produce polyclonal antibodies. By using competitive indirect ELISA(ciELISA), the reactivities of the antibodies toward soy proteins treated with different methods were investigated and shown as $IC_{50}$. $IC_{50}'s$ of anti-ISP antibodies to ISP, ISP(SU), ISP treated with 2-ME(ISP(ME)), and crude 11S were 20, 30, 36, and $1000\;{\mu}g/mL$, respectively. And the values of anti-ISP(SU) antibodies to the same antigens were 100, 5, 4, and $220\;{\mu}g/mL$ and those of anti-AS antibodies were 20, 2, 2.5, and $200\;{\mu}g/mL$, respectively. Therefore, anti-AS antibodies showed the highest reactivities toward soy proteins among the produced antibodies as determined by ciELISA.