• Korean Journal of Agricultural Science
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• v.46 no.3
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• pp.549-557
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• 2019

Staphylococcal enterotoxin is a very common cause of food poisoning. Conventional detection methods for the toxin including enzyme-linked immunosorbent assays (ELISAs), chemiluminescence (ECL), and polymerase chain reaction (PCR) assays require a lot of time, efforts, and expert technicians. Lateral flow strip kits have shown great potential for the rapid detection of foodborne pathogens. The lateral flow strip kit is widely used in clinical settings because it is easy to use, fast, and cost effective. A typical lateral flow strip kit uses colloidal gold to generate a visual signal. However, the lateral flow strip kit based on colloidal gold has limited sensitivity to fulfill food safety regulation requirements. This study was performed to develop a rapid test kit for pathogenic staphylococcal enterotoxin B (SEB) in food samples. The rapid detection kit was fabricated based on a nitrocellulose lateral-flow strip. Cellulose nano beads and SEB antibodies were used as the tag and receptor, respectively, to improve the detection performance. Manually spotted SEB antibody and anti-rabbit antibody on the surface of the nitrocellulose membrane were used as test and control spots, respectively. The feasibility of the rapid test kit to detect SEB in samples was evaluated. The sensitivity of the kit was 10 ng/mL SEB spiked in PBS. Additionally, the rapid test kit could detect 1 ng/mL of SEB in chicken meat extract.

• Journal of Environmental Health Sciences
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• v.38 no.6
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• pp.510-519
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• 2012

Objectives: This study was conducted in order to evaluate the microbiological contamination of the indoor air of the lunchrooms at child care centers and investigate the toxin genes and toxin production ability of food-borne pathogens. Methods: A total of 64 child care centers were sampled to test total aerobic bacteria, coliform bacteria, fungi, Staphylococcus aureus, Bacillus cereus and Salmonella spp. according to the Korea Food Code. All toxin genes of pathogens were detected using the Polymerase Chain Reaction method. The Sthaph. aureus enterotoxin was detected by a Staphylococcus aureus enterotoxin-reversed passive latex agglutination kit. The heamolysin BL (HBL) and non-heamolytic enterotoxin (NHE) produced by B. cereus were detected using a B. cereus enterotoxin-reversed passive latex agglutination kit and Bacillus diarrheal enterotoxin visual immunoassay kit, respectively. Results: The means of total aerobic bacteria and coliform bacteria were $1.91{\pm}1.84$ log CFU/plate and $0.47{\pm}0.62$ log CFU/plate, respectively. The mean of fungi also showed $0.59{\pm}0.71$ log CFU/plate. Among the pathogenic bacteria tested in this study, Staphy. aureus and B. cereus were detected in four (6.3%) and 21 (32.8%) out of 64 indoor air samples from lunchrooms in child care centers, respectively. All Staphy. aureus tested in this study possessed no toxin genes and did not produce enterotoxin. The detection rate of nheABC, hblCDA, entFM and ces toxin gene in B. cereus was 100, 57.1, 76.2 and 0%, respectively. B. cereus isolates were classified into four groups according to the presence or absence of toxin genes. The nheABC gene was the major toxin gene among B. cereus tested in this study. The HBL was detected in 11 out of 21 B. cereus isolates (52.4%) and three B. cereus isolates produced NHE (14.3%). Conclusion: The results indicated that the contamination by microorganisms in the indoor air of lunchrooms was unqualified to supply safe catering in child care centers. The ongoing control of indoor air quality is required.

• Korean Journal of Poultry Science
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• v.39 no.4
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• pp.273-278
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• 2012

Staphylococcal enterotoxin B (SEB), which is a bacterial superantigen produced by Staphylococcus aureus, is associated with serious diseases, including food poisoning and atopic dermatitis. This study was performed to produce about 30 kDa of recombinant SEB protein and to immunize in chickens to acquire the specific egg yolk antibody (IgY) against the recombinant SEB. Chickens were immunized with the recombinant SEB intramuscularly in the breast muscle by injection 3 times at intervals of two weeks. Serum- and egg yolk-antibody titers of hens against SEB were highest at 4 weeks after first immunization. In western blot, anti-recombinant SEB IgY was reacted immunospecifically against the recombinant SEB and commercialized SEB. These results suggested that the recombinant SEB antigen could be used as an immunogen to elicit antibody (IgY) against SEB and the anti-recombinant SEB IgY could neutralized staphylococcal enterotoxin B effectively.

• Korean Journal of Veterinary Service
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• v.25 no.3
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• pp.275-283
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• 2002

Forty strains of Staphylococcus aureus were isolated from mastitic milk. As a result of antimicrobial susceptibility test, the strains of S aureus revealed 47.5% were resistant to ampicillin and penicillin, and 7.5% to gentamicin. But 45% of isolates were sensitive to antimicrobial agents tested. In case of enterotoxin production, 56.3% of 16 strains produced enterotoxin D. Two strain of enterotoxin D producers produced both enterotoxin B and D. According to isolation date, 15 representative strains were selected. As a results of pulsed field gel eletrophoresis analysis of the 15 representative strains, 14 strains were identical. Therefore we consider the identical strains of S aureus have caused continuously bovine mastitis in this dairy farm. If autogenous vaccine can be made by the strains, it will work well for the prevention of bovine mastitis caused by S aureus.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.683-687
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• 2004

Raw beefs used fer Jangzorim production were evaluated fur contamination of pathogenic bacteria and microorganisms related to spoilage and food safety. Eleven groups of mesophilic, psychrotrophic, and anaerobic microorganisms, and total coliforms were selected to evaluate degree of food contamination. Nine strains including Bacillus cereus, Clostridium botulinum, C. perfringens, and Listeria monocytogenes were selected to evaluate incidences of pathogenic bacteria. Raw beefs harbored large populations of microorganisms, which decreased greatly after heat treatment. Psychrotrophic microorganisms were found to be more abundant than other microorganisms. B. cereus, C. perfringens, and L. monocytogenes were isolated from raw beefs, whereas C. botulinum, Escherichia coli O157:H7, Salmonella spp., Shigella spp., Staphylococcus aureus, and Yersinia enterocolitica were not isolated. Isoiates from Cereus selective agar, clostridium Perfringens agar, and Oxford agar were in 99.8, 99.9 and 98.6% agreements with B. cereus, C. perfringens, and L. monocytogenes at species level, respectively. B. cereus produced enterotoxin with CRET-RPLA method, whereas C. perfringens did not produce enterotoxin with PET-RPLA method.

• Applied Biological Chemistry
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• v.51 no.4
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• pp.263-268
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• 2008

Seventy-one Bacillus cereus strains (12 references and 59 food isolates) were analyzed for the occurrence of five different enterotoxin genes (nheABC, hblCDA, entFM, cytK, and bceT) and one emetic toxin cereulide synthetase gene (ces) by PCR (polymerase chain reaction). PCR analysis revealed eight toxigenic patterns in all B. cereus strains tested; they all carried both entFM and nheABC. The presence of hblCDA, cytK, and bceT varied according to the enterotoxin-producing strains, among which hblCDA was the least frequently detected in the food-isolated strains. Only five B. cereus strains harbored ces, associated with the emetic type of food poisoning; however, these strains were devoid of hblCDA, cytK, and bceT.

• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.806-810
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• 1999

A multiplex-polymerase chain reaction (PCR) assay was used to detect staphylococcal enterotoxin production by 12 strains of Staphylococcus aureus isolated from clinical specimens. To evaluate the efficacy and/or sensitivity of this method, the results were compared to those obtained with the reversed passive latex agglutination kit (SET-RPLA, Denka Seiken, Japan). Of 10 strains positive by PCR were positive by RPLA but two strains, representing high sensitivity of the former method. Enterotoxin B was the most prevalent by the two methods. The kappa index between the two methods was 0.826, indicating a higher agreement and fully reliable for use. These results would suggest that sensitive, inexpensive, and relatively rapid multiplex-PCR technique may be an effective means for the detection of staphylococcal enterotoxin genes as an alternative to traditional methods such as kits or immunological methods, which depend upon the amount of enterotoxin produced.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.1
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• pp.27-34
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• 2005

Biochemical characteristics, enterotoxin production and antimicrobial susceptibility were determined for 30 strains of Bacillus cereus isolated from stool specimens of diarrhea patients at an university hospital in Chulabuk-do province. Positive rate for VP reaction and citrate utilization were lower, (33 % and 40 % respectively) while the rates of acid production from mannitol, arabinose, and xylose were higher (17 %, 13 % and 3 % respectively) than those obtained by other investigators. The enterotoxin gene was detected in 18 of 30 isolates (60 %) by PCR, and the toxin was detected from all of the toxin gene-positive isolates by RPLA test. The agar dilution test showed that all isolates were resistant to penicillin G and 73 % were to cephalothin, but all were susceptible to ciprofloxacin, clindamycin, erythromycin, fusidic acid, gentamicin, rifampin, teracycline and vancomycin. We conclude that B. cereus isolates producing acid from mannitol, arabinose and xylose exist, that PCR can be used to detect enterotoxin genes rapidly and accurately, and that this organism is susceptible to various antimicrobial agents though not penicillin G and cephalothin.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.425-429
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• 2003

Staphylococcus aureus is a major pathogen for cattle, causing various forms of subclinical and clinical mastitis and could be a causative agent of food poisoning, it produces various superantigenic exotoxins which have a great public health significance. A total of 72 S. aureus clinical isolates from dairy farms located in Kyunggi Province Korea were examined for the species identification by biochemical method, and for the detection of $\beta$-lactamase, enterotoxin and other exotoxins genes by PCR. The results of species identification by biochemical method agreed with those of PCR done with species specific primer STA-AU. $\beta$-lactamase is an enzyme closely associated with the resistance to antibiotic penicillin, which is an important means of treatment of mastitis, all the isolates were positive for the presence of genes encoding $\beta$-lactamase, which were reproduced in penicillin susceptibility disc assay. Six types of toxin genes, Staphylococcal enterotoxin (SE)A, SEB, SEC, SEE, toxic shock syndrome toxin (TSST-1) and exfoliative toxin A (ET A) were detected in 72 isolates by PCR associated genotypic method in this study, none of the isolates carried the genes for enterotoxin D (SED) and exfoliative toxin B (ETB). The occurrence rate of exotoxin genes rated as 12.5%, and the precision of the PCR identification results has been confirmed using the reference strains.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.97-102
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• 2003

Raw and washed spinaches were tested to evaluate the incidences of Aeromonas hydrophila, Escherichia coli O157:H7, Plesiomonas shigelloides, Pseudomonas aeruginosa, Salmonella spp., Shigella spp., Yersinia enterocolitica, Bacillus cereus, Campylobacter jejuni, Clostridium perfringens, Listeria monocytogenes, and Staphylococcus aureus. Four pathogenic bacteria were isolated from spinach samples, and identified by morphological and biochemical methods, including API and ATB identification systems. Isolates from MacConkey, Cereus Selective, Clostridium Perfringens, and Baird-Parker agar media were in 99.9, 99.8, 99.9, and 97.8% agreements with A. hydrophila, B. cereus, C. perfringens, and S. aureus at the species level, respectively. SET-RPLA revealed, among the five strains of S. aureus isolates, two produced type A enterotoxin. All five strains of B. cereus isolates produced enterotoxin as revealed with CRET-RPLA.