Yong-Bae Park

Gyeonggido Institute of Health and Environment, Sŏul, Seoul, South Korea

Are you Yong-Bae Park?

Claim your profile

Publications (18)15.15 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Toxin producing Bacillus cereus can cause enterotoxic and/or emetic food poisoning. In the present study, a multiplex PCR assay was developed to detect all toxin genes known to be involved in food poisoning of B. cereus in a single reaction. Specific primers for the detection of enterotoxic (entFM, hblC, nheA, and cytK) genes and emetic toxin production (2 primer pairs: ces, CER) were designed based on the GeneBank sequences. The developed multiplex PCR assay was evaluated in pure culture and artificially inoculated milk, using 43 B. cereus strains and non-target strains. In brief, sensitivity in pure culture was 10-fold or more higher than artificially inoculated milk in multiplex PCR detection limit assay. The presented PCR assay is a developed molecular tool for the rapid simultaneous detection of emetic and enterotoxin producing B. cereus strains.
    Food science and biotechnology 10/2012; 21(21(5)-DOI 10.1007/s10068-012-0189-8):1439-1444. · 0.70 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The monitoring of pesticide residues was performed on 33 fruit commodities collected in Gyeonggi-do, Korea from 2006 to 2010. Pesticide residues were detected in 431 samples (16.8%) of total 2,558 samples and violated in 12 samples (0.5%). Annual detection rate showed 6.9%~19.4% with the rate of violation of 0.3%~0.9%. Twenty three samples (69.7%) of 33 commodities were detected and 4 samples (12.1%) were violated. Eight pesticides (EPN, dicofol, carbaryl, procymidone, methidathion, prothiofos, fenitrothion and phenthoate) were violated and 62 pesticides were detected. Chloropyrifos was detected most frequently. The rate of detection and violation of citrus fruits in fruits showed the highest level. Organophosphorus pesticides (35%) and insecticide (57%) were detected most frequently. The hazard index (%ADI) of chronic dietary risk assessment by deterministic approach showed that the lower limit value and upper limit value for the whole population were 0.0000~0.7526 and 0.0000~1.3237 respectively. For the only consumer group, the lower limit value and upper limit value were 0.0006~9.7801 and 0.0058~15.9258 respectively. Therefore the hazard index for the whole population and the only consumer group were evaluated as a safe level.
    The Korean Journal of Pesticide Science. 01/2012; 16(2).
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We encountered a patient with hemolytic uremic syndrome (HUS) with persistent isolation of shiga toxin-producing Escherichia coli (STEC) for 3 weeks despite of having no clinical symptoms. STEC has been recognized as an important food-borne pathogen that causes severe diseases such as HUS. We characterized this STEC strain via a polymerase chain reaction, reverse-passive latex agglutination and the slide agglutination method. In this STEC strain, stx2 (shiga toxin), eaeA, tir, iha (adherence genes), espADB (type III secretion genes), and hlyA, ehxA, clyA (hemolysin genes) were present. The O antigen of the strain was non-typable.
    Yonsei medical journal 11/2011; 52(6):1039-43. · 0.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study was conducted to investigate the phenotypic and genotypic characteristics of Korean isolates of Cronobacter spp. (Enterobacter sakazakii). A total of 43 Cronobacter spp., including 5 clinical isolates, 34 food isolates, 2 environmental isolates, and 2 reference strains (C. sakazakii ATCC 29004 and C. muytjensii ATCC51329) were used in this study. Korean isolates of Cronobacter spp. were divided into 11 biogroups according to their biochemical profiles and 3 genomic groups based on the analysis of their 16S rRNA gene sequences. Biogroups 1 and 2 contained the majority of isolates (n=26), most of which were contained in 16S rRNA cluster 1 (n=34). Korean isolates of Cronobacter spp. showed diverse biochemical profiles. Biogroup 1 contained C. sakazakii GIHE (Gyeonggido Research Institute of Health and Environment) 1 and 2, which were isolated from babies that exhibited symptoms of Cronobacter spp. infection such as gastroenteritis, sepsis, and meningitis. Our finding revealed that Biogroup 1, C. sakazakii, is more prevalent and may be a more pathogenic biogroup than other biogroups, but the pathogenic biogroup was not represented clearly among the 11 biogroups tested in this study. Thus, all biogroups of Cronobacter spp. were recognized as pathogenic bacteria, and the absence of Cronobacter spp. in infant foods should be constantly regulated to prevent food poisoning and infection caused by Cronobacter spp.
    Journal of Microbiology and Biotechnology 05/2011; 21(5):509-14. · 1.40 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: HPLC method for quantitative determination of four preservatives and nine UV filters worldwide authorized in commercial suncare product was developed and validated, and then 101 samples of commercial suncare products were analyzed for the UV filters and preservatives using the proposed method. The mobile phase was acetonitrile-water containing 0.5% acetic acid using a gradient elution at a flow rate of 0.9 mL/min and UV measurements were carried out at 320 nm for UV filters and 254 nm for preservatives. The correlation coefficients of each calibration curves were mostly higher than 0.999. The percent relative standard deviations (%RSD) ranged from 0.97% to 6.1% for five sample aliquots. The recoveries from the spiked solutions were 98-102%. 2-ethylhexyl-p-methoxycinnamate (EHMC) was detected in 96 of 101 commercial suncare products and the concentration was in the range of 3.08-8.16% and 18 samples were found to exceed the 7.5% which has been defined as the maximum allowed concentration in Korea. Methyl paraben was detected in 81 of 101 samples and the next-most often detected preservatives were propyl paraben (25), ethyl paraben (18), and butyl paraben (4). Three samples of 101 suncare products exceeded the maximum allowed concentration (i.e., 0.58-0.79%). The proposed HPLC method allows efficient and simultaneous analysis of preservatives and UV filters suitable for quality control assays of commercial suncare products.
    Journal of chromatographic science 01/2011; 49(7):554-9. · 0.79 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The prevalence, genetic diversity, and antibiotic susceptibility of Cronobacter species (Enterobacter sakazakii) isolated from sunshik products, its ingredients, and root vegetable farm’s soils were investigated to analyze main reservoirs and contaminated sources of Cronobacter spp. Cronobacter spp. was isolated from 9 of 15 sunshik products, 26 of 72 its ingredients, and 2 of 39 soils. The root vegetables such as sweet potato and carrot showed higher contamination rate (70%) than the other sunshik ingredients. All isolates showed 929 bp band amplified from 16S rRNA and resistant to ampicillin, amoxicillin/clavulanic acid, and cefazolin. All isolates showed diverse random-amplified polymorphic DNA (RAPD) and pulsed-field gel electrophoresis (PFGE) band patterns. However, 3 cases of RAPD banding patterns between clinical strains and isolates from sunshik products and root vegetables (yam, carrot) were related with similarities level of 80%. These studies indicated that root vegetables can be an important contamination source of Cronobacter spp. in sunshik products. Thus, the preparation of root vegetables for manufacturing sunshik products used as a weaning diet was handled with more care than the other sunshik ingredients. Keywords Cronobacter species–reservoir–root vegetable–genotyping–antibiotic susceptibility
    Food science and biotechnology 01/2011; 20(4):941-948. · 0.70 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Bacillus cereus can cause the diarrheal and emetic type of food poisoning but the symptoms of emetic food poisoning caused by B. cereus occasionally include emesis and diarrhea. The enterotoxin characteristics of emetic toxin (cereulide) producing B. cereus were needed to be determined. Therefore, forty B. cereus strains isolated from various sources in Korea were investigated for the presence of enterotoxin genes. All strains were confirmed to produce the emetic toxin using HPLC-MS methods. The rates of the nheABC, hblCDA, entFM and cytK genes amongst emetic toxin producing B. cereus strains were 82.5, 7.5, 50.0 and 27.5%, respectively. Pattern III harbored nheABC and entFM genes and pattern V processed entFM gene and were shown to be the major patterns, being present in 55.0% (21 of 40) of the emetic toxin producing B. cereus strains. Our findings revealed that 34 (85.0%) of 40 emetic toxin producing B. cereus strains isolated in Korea have the potential to cause diarrheal and emetic type of food poisoning, simultaneously. Thus, emetic toxin and enterotoxin genes should be constantly screened to provide insight into B. cereus food poisoning.
    International journal of food microbiology 11/2010; 144(1):182-6. · 3.01 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Because conventional methods for detecting emetic-toxin-producing B. cereus are laborious and costly, various PCR assays, which are easy and cheap, have recently been reported. Therefore, this study estimated and compared the ability of various PCR assays to detect emetic-toxin-producing B. cereus strains isolated in Korea. The PCR assays were performed on 160 B. cereus strains, including 40 emetic-toxin-producing strains. Although the species-specific PCR assays were all shown to be highly specific, the sensitivities varied greatly. The accuracies of the primers were 97.5% (CER), 95.6% (EM1), 96.3% (RE234), 89.4% (CES), and 83.1% (Ces3R/CESR2). Moreover, the CER primer had a higher sensitivity (100%) than all the other primers tested, and a specificity of 96.7%. Thus, the CER primer was shown to be the most effective for screening the emetic-toxin-producing B. cereus strains tested in this study. However, the ability of these PCR assays to identify emetic-toxin-producing B. cereus should also be confirmed using other methods.
    Journal of Microbiology and Biotechnology 07/2010; 20(7):1107-13. · 1.40 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Bacillus cereus was divided into emetic toxin (cereulide)- and enterotoxin-producing strains, but emetic toxin-producing B. cereus is difficult to detect immunochemically. Screening methods for emetic toxin-producing B. cereus are needed. The objectives of this study were to identify and detect emetic toxin-producing B. cereus among 160 B. cereus strains, and to compare enterotoxin production and phenotypic characteristics between the emetic toxin-producing and enterotoxin-producing strains. Forty emetic toxin-producing B. cereus strains were determined with high-pressure liquid chromatography-mass spectrometry analysis. Among the emetic toxin-producing strains (n = 40), 31 (77.5%) and 3 (7.5%) strains produced nonhemolytic enterotoxin (NHE) and hemolysin BL (HBL) enterotoxins, respectively. In addition, 107 (89.2%) and 100 (83.3%) strains produced NHE and HBL enterotoxins among the enterotoxin-producing strains (n = 120). The number of strains positive for starch hydrolysis, salicin fermentation, and hemolysis among the emetic toxin-producing strains were 3 (7.5%), 3 (7.5%), and 26 (65.0%), respectively, and among enterotoxin-producing strains, these numbers were 101 (84.2%), 100 (83.3%), and 111 (92.5%), respectively. In particular, the three emetic toxin-producing B. cereus strains (JNHE 6, JNHE 36, and KNIH 28) produced the HBL and NHE enterotoxins and were capable of starch hydrolysis and salicin fermentation. The absence of HBL enterotoxin and certain phenotypic properties, such as starch hydrolysis and salicin fermentation, indicates that these properties were not critical characteristics of the emetic toxin-producing B. cereus tested in this study.
    Journal of food protection 07/2010; 73(7):1219-24. · 1.83 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Bacillus cereus can cause diarrheal and emetic types of food poisoning but little study has been done on emetic type of food poisoning in Korea. The objective of this study was to report on the emetic type of food poisoning associated with B. cereus in Korea. The toxin gene profile, toxin production, and antibiotic resistance of B. cereus isolates were investigated in this study. B. cereus was detected in three out of four samples, while the other food poisoning bacteria were not detected. All isolates (KUGH 10, 11, and 12) presented nhe A, B, and C diarrheal toxin genes (755, 743, and 683 bp), detected using NHA, NHB, and NHC primers, and ces emetic toxin gene (1271 bp), detected using CES primer, and produced nonhemolytic enterotoxin and emetic toxin (cereulide), detected using immunochemical assay and high performance liquid chromotography/mass spectrometry (HPLC/MS) analysis. All emetic-associated isolates were resistant to beta-lactam antibiotics. Most important finding in this study was that the risk of emetic-type B. cereus food poisoning has existed in Korea. This suggested that the food poisoning caused by B. cereus producing emetic and diarrheal toxins should be constantly evaluated to prevent misdiagnosis between emetic and diarrheal types of food poisoning.
    Foodborne Pathogens and Disease 05/2010; 7(5):555-63. · 2.28 Impact Factor
  • Journal of the Korean Society of Food Science and Nutrition 01/2010; 39(4):526-534.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Incidence and properties of Bacillus cereus strains naturally present in cereals were evaluated by phenotypic characterization, antibiotic susceptibility testing, and pulsed-field gel electrophoresis. Of 293 cereal samples tested, 73 (25%) contained B. cereus strains. Incidence of B. cereus isolates varied with respect to sample; they were found in 15 (37%) of 83 brown rice samples, 23 (37%) of 63 glutinous rice samples, 16 (21%) of 76 barley samples, and 19 (27%) of 71 Job's tears samples. All B. cereus isolates from cereals were positive for diarrheal toxin genes. The isolates were susceptible to most of the antibiotics tested, but they were highly resistant to ampicillin, cefepime, oxacillin, and penicillin. Of the genes assayed by the PCR technique, a high frequency of nheA (99%) and hblDC (84%) was found in the genomic DNA of cereal-associated isolates, whereas cytK was less common (55%). From the strains carrying the hblDC genes, 93% produced enterotoxin HBL. B. cereus isolates did not have significant genetic homology. The genetic diversity and toxic potential differ among the strains isolated from cereals. These results provide important information on toxin gene profiles of cereal-associated B. cereus for population studies.
    Journal of food protection 04/2009; 72(3):612-7. · 1.83 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The objectives of this study were to compare the biochemical profiles with biogroups for the identification of Cronobacter spp. (formally known as Enterobacter sakazakii) isolates using biochemical identification kits. A total of 38 Cronobacter spp. contained 5 clinical, 31 food, and 2 environmental isolates were used. All isolates were identified as Cronobacter spp. with the Vitek II system and ID 32E kit. The API 20E kit identified all isolates as Cronobacter spp. but the percentage identification was 51.1% for 16 of 38 isolates. These strains were contained to Biogroup 2, 9, 10, and 11. The utilization of inositol is a factor determining the percentage identification of Cronobacter spp. with the API 20E kit.
    Journal of Food Hygiene and Safety. 01/2009; 24(4).
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A gene encoding O-methyltransferase (SOMT)-10 from soybean, SOMT-10, was cloned by reverse transcription polymerase chain reaction. Phylogenetic analysis revealed that SOMT-10 belonged to caffeoyl-CoA O-methyltransferase (CCoAOMT) and contained conserved catalytic residues found in CCoAOMT. SOMT-10 was expressed in Escherichia coli as a glutathione S-transferase fusion protein and purified to determine its substrate. Several compounds including caffeoyl-CoA, naringenin, quercetin, caffeic acid, kaempferol and luteonin were tested as substrates for the purified recombinant SOMT-10. Analysis of reaction products using high performance liquid chromatography revealed that SOMT-10 used caffeoyl-CoA, quercetin and luteolin as substrates. This result indicated that SOMT-10 used flavones having vicinal hydroxyl groups. The methylation position was determined to be the 3′ hydroxyl group. It is likely that SOMT-10 is a new class of OMT that uses not only caffeoyl-CoA, but also flavonoids. Molecular docking of tricetin with the modeled structure SOMT-10 disclosed that SOMT-10 showed all combinations of the O-methylated products.
    Journal of the Korean Society for Applied Biological Chemistry 01/2009; 52(2). · 0.43 Impact Factor
  • Source
    Journal of Bacteriology and Virology 01/2008; 38(2).
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Enterobacter sakazakii was initially referred to as yellow-pigmented Enterobacter cloacae and reclassified in 1980. E. sakazakii infection cause life-threatening meningitis, septicemia, and necrotizing enterocolitis in infants. Powdered infant formula (PIF) and baby foods may be the important vehicle of E. sakazakii infection. It has been reported that E. sakazakii was isolated from PIF and sunsik ingredients produced in Korea. Some infants have been fed sunsik as a weaning diet. Therefore, it is necessary that this organism should be inactivated on preparing PIF and sunsik at homes and in hospitals. The cocktail of three Korean E. sakazakii strains (human, sunsik and soil isolates) were used to investigate the inactivation of this organism with hot water at 50, 60, 65, 70 and and microwave heating for 60, 75, 90, 105 and 120 sec. Reconstituted PIF and sunsikwere inoculated with cocktailed vegetative cells of E. sakazakii at 6 log CFU/mL. Thermal inactivation of vegetative cells of E. sakazakii were achieved by reconstituted PIF and sunsik with hot water at or greater and with microwave heating at 2,450 MHz for 75 sec or longer. Considering that biofilm formation of E. sakazakii was adapted to survive the dry environment that is PIF and sunsik and thermal resistance increased, it is suggested that inactivation of E. sakazakii was used by hot water at or greater and microwave heating for 90 sec or longer. Reconstituted PIF and sunsik were inoculated with cocktailed vegetative cells of E. sakazakii at 2 to 3 log CFU/mL to investigate the growth curve of this organism and stored at 5, 10, 15, 20, 25, 30 and . Viable counts slightly changed at 5, during 48 h but grew at or greater. Considering that E. sakazakii is able to grow in infant formula milk at refrigerator temperature, reconstituted PIF and sunsik that are not immediately consumed should be discarded or stored at refrigeration temperatures within 24 h.
    Journal of Food Hygiene and Safety. 01/2008; 23(2).
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Ninety two samples of child-consumed candies and candy packages were analyzed for seven heavy metals. Lead (Pb) was detected at concentrations of 110.3–6394.1 mg kg−1 in ten of 92 candy packages. The directive factor of Pb contamination had originated in the lead-based ink of the outer cover. Particularly, Pb was detected at high concentrations in case of green- or yellow-colored packages. Chromium (Cr) was detected at high concentrations in cases where Pb was also detected at high concentrations, and the Cr levels ranged from 136.9 mg kg−1 to 1429.3 mg kg−1 in seven of the 92 candy packages. Hexavalent chromium [Cr(VI)] was detected at 87–105.0% of the total Cr in polypropylene-coated wrappers with printed outer covers. The migration of Cr(VI) increased with elution time up to 0.20 μg (cm2)−1 for 30 days in basic (pH 10.0) solution; however, there were no migrations in acidic (pH 4.0) and neutral (pH 7.0) solutions. The migration of Pb increased with elution time up to 0.65 μg (cm2)−1 and 0.28 μg (cm2)−1 in basic (pH 10.0) and acidic (pH 4.0) solutions, respectively. However, any migration was hardly observed in neutral (pH 7.0) solution.
    Food Research International. 01/2008;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Trans fatty acid components separated and quantified using a SP-2560 capillary column in a gas chromatograph (GC) with flame ionization detector (FID). Trans fatty acid and total fatty acid contents were measured in 21 corn oils. Ranges of values for trans fatty acid (tFAs) contents of total fat (as g/100g fatty acids) were com oils . Corn oils were heated at for 5mins . The contents of tFAs (g/100) were increased from 0.292 (0 time) to 2.585 (15 times) in com oil. When frying oils (15 times) were incubated at for 150 days, the contents of tFAs (g/100g) were increased from 2.585 to 3.683 in com oil. The amounts of tFAs (g) per serving size of frying oils (15 times) were increased from 0.01 to 0.18 in corn oil. The levels of the 18:1 trans isomers increased significantly the time of reusing of com oil.
    Journal of Food Hygiene and Safety. 01/2007; 22(4).