Search

Noroviruses (NoVs) are the most common causes of epidemic gastroenteritis, responsible for at least 50% of all gastroenteritis outbreaks worldwide and significant causes of foodborne illness. In the USA, approximately 21 million illnesses attributable to NoVs have annually occurred. Therefore, there is a great demand to develop a rapid, low-cost, and accurate detection method for NoVs. This study first reported colorimetric helicase-dependent amplification (HDA) methods based on specific primers integrated with HRPzyme for the rapid and sensitive detection of NoV GI and GII. The colorimetric HDA methods exhibited a detection limit of 10 copies mL

Shellfish-growing areas in marine environments are affected by pollutants that mainly originate from land, including streams, domestic wastewater, and the effluents of wastewater treatment plants (WWTPs), which may function as reservoirs of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs). The objective of this study was to identify the occurrence and distribution of antibiotic resistance at five oyster sampling sites and 11 major inland pollution sources in the drainage basin of Kamak Bay, Republic of Korea. Culture-based methods were used to estimate the diversity and abundance of antibiotic-resistant Escherichia coli strains isolated from oysters and major inland pollution sources. The percentages of ARB and multiple antibiotic resistance index values were significantly high in discharge water from small fishing villages without WWTPs. However, the percentages of antibiotic-resistant E. coli isolates from oysters were low, as there was no impact from major inland pollutants. Fourteen ARGs were also quantified from oysters and major inland pollution sources. Although most ARGs except for quinolones were widely distributed in domestic wastewater discharge and effluent from WWTPs, macrolide resistance genes (ermB and msrA) were detected mainly from oysters in Kamak Bay. This study will aid in tracking the sources of antibiotic contamination in shellfish to determine the correlation between shellfish and inland pollution sources.

Since the contamination of Listeria species is considered as a serious problem in public health and food industries, a rapid, accurate, and easy-to-use detection method is highly demanded. The objective of this study is to develop a colorimetric loop-mediated isothermal amplification (cLAMP) assay using a molecular beacon for the rapid and sensitive detection of Listeria species in enoki mushroom. The detection limit of the method optimized at 59.7 °C for 6 Listeria species in buffer was all 1 × 100 CFU/mL, and the cLAMP was confirmed to be specific to 6 major Listeria species. The period required to complete the cLAMP was within 1 h. The cut-off value of the method for the artificially inoculated mushroom samples was 1 × 101 CFU/g. This study suggests that the cLAMP is expected to be used as a point-of-care molecular diagnostic technology because the method does not require any expensive instruments.

The present study investigated the distribution and antimicrobial susceptibility patterns of Vibrio parahaemolyticus in water samples and aquatic animals (fish and shrimp) from major aquaculture farms along the Korean coast in 2018. V. parahaemolyticus is the most common pathogen causing seafood-borne illness. The strain was detected in 34.7% of all samples tested, and was detected at higher levels during summer to autumn when the water temperature is higher. Although more than 90.0% of V. parahaemolyticus isolates were sensitive to 13 of the 15 antimicrobials tested, which is useful for treating V. parahaemolyticus infectious disease, the isolates exhibited higher resistance to two antibiotics (colistin and ampicillin), which should be excluded as treatment options for these infections. Koreans typically enjoy consuming raw seafood. To reduce the potential human health risk of raw seafood consumption, the prevalence and antimicrobial resistance of V. parahaemolyticus in aquaculture environments should be continuously valuated.

We assessed the levels of fecal contamination and the originating species of 12 major inland pollutants in the drainage basin of Yeoja Bay. The presence of the human-specific (HF183), ruminant-specific (BacR and Rum-2-Bac), pig-specific (Pig-Bac-2 and Pig-2-Bac), avian-specific (GFD), and gull-specific (Gull2) markers in water samples (n = 34) from 12 inland pollution sources around Yeoja Bay was analyzed. HF183 was detected in 97% of the water samples, and all major inland pollution sources were contaminated with human feces. BacR and Rum-2-Bac were detected in 94% and 11%, respectively, of the water samples. Pig-2-Bac was not detected in the inland pollution sources, but site L5 might be contaminated with swine feces. Gull2 was not detected, whereas GFD was detected in 26% of the water samples. This study highlights the utility of a MST toolbox approach for characterizing the water quality of inland pollution sources and identifying the feces producing species.

This study investigates the effects of dielectric barrier discharge (DBD) plasma treatment (1.1 kV, 43 kHz, N2 1.5 L/min, 10~60 min) on human norovirus (HuNoV) GII.4 infectivity in fresh oysters. HuNoV viability in oysters was assessed by using propidium monoazide (PMA) as a nucleic acid intercalating dye before performing a real-time reverse transcription&ndash, quantitative polymerase chain reaction (RT-qPCR). Additionally, the impact of the DBD plasma treatment on pH and Hunter colors was assessed. When DBD plasma was treated for 60 min, the HuNoV genomic titer reduction without PMA pretreatment was negligible (&lt, 1 log copy number/&micro, L), whereas when PMA treatment was used, HuNoV titer was reduced to &gt, L in just 30 min. D1 and D2-value of HuNoV infectivity were calculated as 36.5 and 73.0 min of the DBD plasma treatment, respectively, using the first-order kinetics model (R2 = 0.98). The pH and Hunter colors were not significantly different (p &gt, 0.05) between the untreated and DBD-plasma-treated oysters. The results suggest that PMA/RT-qPCR could help distinguish HuNoV infectivity without negatively affecting oyster quality following &gt, 30 min treatment with DBD plasma. Moreover, the inactivation kinetics of nonthermal DBD plasma against HuNoV in fresh oysters might provide basic information for oyster processing and distribution.

This study investigated the effects of thermal treatment (70, 80, and 90 °C for 5, 10, and 20 min) on the titers of human norovirus (HuNoV) GII.4, a dominant genotype in fresh mussels using propidium monoazide (PMA) pretreatment and real-time reverse transcription quantitative-polymerase chain reaction (RT-qPCR) and the effects of thermal treatment on mussel quality (Hunter colors and sensory properties). Reductions of >1-log10 for HuNoV in PMA-treated mussels required 70 °C for 20 min, 80 °C for 10 min and 90 °C for 5 min. As assessed by PMA/RT-qPCR, the log10 reduction values of HuNoV in PMA-treated samples was significantly reduced (46% or 0.27 log10; P

Ochratoxin A (OTA), a mycotoxin classified as a potentially carcinogenic to humans, is slightly soluble in water. In this study, the transfer rate of OTA in herbal medicines to decoctions was investigated. Herbal medicine decoctions were prepared by boiling and autoclaving herbal medicines contaminated with OTA after soaking and not soaking in water. OTA amounts in decoctions and residues were analyzed using HPLC. Transfer of OTA (12.72–61.33%) from herbal medicines to decoctions was observed. Soaking and autoclaving steps enhanced the transfer rate of OTA to decoctions. The results meant that there is a potential risk for consumption of herbal medicine decoctions. Therefore, regular monitoring for mycotoxins, including OTA, in herbal medicines and proper management to ensure the safety of herbal medicines is necessary to protect consumers.

From 2008 to 2013, the mussel Mytilus galloprovincialis were collected from a major area of mussel production (Changseon area), which is a designated shellfish-cultivating area for export, located on the southern coast of Korea. The samples were analyzed for mercury (Hg) using a direct Hg analyzer and for other metals, such as cadmium (Cd), lead (Pb), arsenic (As), chromium, copper, nickel, and zinc, using inductively coupled plasma mass spectrometry. The concentrations and bioaccumulation of the heavy met- als were determined, and a potential risk assessment was conducted to evaluate their hazards towards human consumption. The concentration and bioaccumulation ratio of Cd were the highest of the three hazardous metals (Cd, Pb, and Hg). The concentrations of hazardous metals in all samples were within the limits set by Korea and other countries. The estimated dietary intake (EDI) was compared to the provisional tolerable daily intake (PTDI) adopted by the Joint FAO/WHO Expert Committee on Food Additives and the U.S. Environmental Protection Agency. The EDIs of all heavy metals tested for mussel samples ranged from 0.01 to 4.99% of the PTDI; the highest value was measured for As. The hazard index (HI) can be used to assess the risk of heavy metal consump- tion associated with contaminated food. The HI for all samples was far less than 1.0, which indicates that the mussels produced in the Changseon area do not represent an appreciable hazard to humans and are fit for consumption.

The influences of inland pollution sources nearJeokyang and Jangpoports following rainfall events on the bacteriological water quality and safety of commercial shellfish were investigated in the Changseon area, Korea. Stream flow rates exhibited 1.9- to 5.7-fold increases after rainfall events and then fell to 68~81% of that level after 24 h. The calculated impact area of inland pollution sources was 0.47 in the Jeokyangport area and 0.27 in the Jangpoport area at 24 h following 11 mm of rainfall. When the flow rate of inland pollution increased, the level of male-specific bacteriophage (MSB) decreased, and no MSB could be detected in seawater samples, whereas 30 PFU/100 g was detected in shellfish samples. Fecal coliform levels in seawater and shellfish samples did not exceed their respective tolerance levels (4.5 MPN/100 mL) and 130 MPN/100 g, respectively and thus complied with the standard for approved shellfish growing area. The sanitary conditions of areas adjacent to Jeokyang and Jangpoports under conditions of rainfall below 29 mm met the criteria for approved growing area under the United States National Shellfish Sanitation Program and the EC Regulations.

To evaluate the bacteriological water quality in Yongnam-Gwangdo, located in western Jinhae Bay, seawater samples were analyzed using sanitary indicator bacteria at 57 sampling stations. According to survey results from January 2007 to December 2009, the range of the geometric mean and the estimated 90th percentile for coliforms and fecal coliforms in the samples were

Recently as the user experience`s importance has been emphasized, there has been many tries of various research methodology in order to understand the user. Specially, as the political investigation method`s user understanding method based on the statistical analysis so far has encountered a limit, there has been a continuous tendency to try to introduce a humanitarian or cultural anthropological methodology. As part of this effort, there has been many tries of various approach methods of the Ethnography which is the cultural anthropological typical research methodology, but among those the Diary Study Method is mentioned as one of the effective methodologies. Therefore this thesis applies the Diary Study Method to the notebook PC bundle SW`s attitude research and tries a deep rooted research about the user attitude. Also centered to the project of understanding the notebook PC bundle SW`s user receptivity. it shows a specific example of the Diary Study applied to the user understanding. Through this process, we will examine the summary about the Ethnography research method, and will discuss an effective research methodology by through the process of analyzing and deducting the user inclination by applying and designing the Diary Study to the project. That is to say, it was progressed by actually applying the research methodology through a specific case, with the purpose of breaking away from the textbook discussion and progress with an application aspect discussion. Through the current research, we will verify an active user-inclined process about the user`s notebook PC SW, and it is expected to be useful in establishing a SW UX strategy and distribution related to the bundle software.

Usually, bundled software is unwittingly packaged with a user`s PC when purchased it. A reason of provides it is for manufacturers to increase the value of the product. However, almost users cannot recognize bundled SW. Paradoxically, sometimes the bundled SW may complain to the user. Eventually these symptoms negatively affect the product. As a result, the SW bundle could not reflect user needs. This study for installed bundled SW on users laptop and we would like to know the understanding and acceptance it of the user. Finally, how can we provides it more effectiveness and looking for ways to make was conducted. From a user perspective, these study four major countries (USA, Germany, China, South Korea) laptop users to perform a total 3,000 people were surveyed. A method of investigation was the quantitative evaluation survey and was conducted online survey approach. Through this study was an analysis to awareness of users by different ages, gender, and usage patterns. Bundle SW through the study of the laptop to the user, effectively providing a way to be confirmed. And right through bundle SW distribution is expected to increase the manufacturer`s worth.

In coastal areas that are affected by continuous, seasonal or occasional pollution sources, bivalves accumulate biological contaminants such as pathogenic bacteria. We investigated the effect of natural seawater relaying and electrolyzed seawater depuration on the bacteriological quality of artificially contaminated oysters Crassostrea gigas and short-necked clams Ruditapes philippinarum to suggest an alternative method of shellfish sanitation control.When artificially contaminated oysters and short-necked clams (fecal coliform level 1,700 MPN/100 g) were relayed into a sea area of safe bacteriological water quality, the fecal coliform level dropped to below 110 MPN/100 g after 1 day. The bacteriological quality of oysters and short-necked clams that are contaminated at a fecal coliform level of 1,700 MPN/100 g could be improved, and become appropriate for raw consumption by a single day relay under proper environmental conditions. When artificially contaminated oysters (fecal coliform level 330 MPN/100 g) were depurated with electrolyzed seawater, 94% of fecal coliform was eliminated after 12 h and fecal coliform was undetectable after 24 h. After 24 h depuration with electrolyzed seawater, the fecal coliform level of short-necked clams with initial fecal coliform of 2,400 MPN/100 g was below 20 MPN/100 g. However, the fecal coliform level of short-necked clams with initial fecal coliform of 17,000 MPN/100 g was relatively high, at 790 MPN/100 g, even after 24 h of depuration with electrolyzed seawater, because of the repeated cycle of excretion and accumulation of fecal coliform in shellfish tissue under the closed depuration environment. Such natural seawater relaying and electrolyzed seawater depuration can be restrictively applied to improve or secure the bacteriological quality of oysters and short-necked clams in accordance with safety levels for bivalves for raw consumption.

In 2007, pet food contaminated with melamine caused hundreds of dogs and cats to develop renal failure all over the world. In 2008, over 294,000 infants consumed infant formula and developed kidney stones in China. Further investigation revealed that fish feed also contained melamine; this raised concerns about melamine residues in edible fish tissues, which could have caused the urinary tract stone epidemic. In Korea, catfish fed with assorted feed that included cuttlefish organs that contained melamine developed whitening syndrome and fell dead in some populations in 2008. This event raised suspicions about the toxicity of melamine and all feeds containing melamine were immedi-ately recalled. In this study, we investigated the rates of melamine accumulation and depletion in muscle and viscera of catfish to propose proper withdrawal periods. One group of catfish was fed a commercially available diet that con-tained 30, 100 and 300 mg melamine per kg diet for 14 days. To investigate residual melamine contents in muscle and viscera, other experimental groups were fed a melamine free diet after being fed melamine for 7 days. The residual amount of melamine was analyzed by LC-MS/MS. The melamine concentration in muscle was estimated to be 3.7 mg/kg after 6 days of feeding with a diet containing 300 mg melamine/kg. After 2 days of culture with a melamine free diet, the residual melamine was depleted and the concentration had decreased from 1.15 mg/kg to 0.19 mg/kg in the muscle of catfish fed a diet containing 300 mg melamine/kg for 7 days. The residual amount of melamine was reduced to 0.03 mg/kg in muscle after 7 days of culture with a melamine free diet and was undetectable after a pro-longed culture period of 14 days. Catfish tend to excrete melamine rapidly after oral administration and changes in body color were not observed during the short dosing period. Key words: Melamine, Catfish, LC-MS/MS

The influences of inland pollution sources because of rainfall events on the bacteriological water quality in Geoje Bay, a major shellfish production area in Korea, were investigated. The sanitary status of sea water and shellfish after rainfall events was also evaluated. The flow rates of 13 streams around Geoje Bay showed 6 to 7-fold increases after 15 to 21 mm of rainfall. Peak pollution was observed in the Naegan Stream, the Gandeok Stream and the Seojeong Stream. The calculated impact area of inland pollution sources was 3.1 ㎢ immediately after 15 mm of rainfall and expanded to 3.5 ㎢ after 24 hours. These calculations of impacted area matched results from fecal coliform analyses with sea water. The distance between the major pollution source in the bay (the Gandeok Stream) and the station with the worst bacteriological water quality immediately after 15 mm of rainfall, which was below the Korean standard, was 0.8 km in a straight line; this distance increased to 2.0 km after a period of 24 hours. The area impacted by inland pollution sources after a 15 mm rainfall event was wider than after a 21 mm rainfall. Although the flow rate from in-land pollution sources was higher, the concentration of fecal coliform in the discharged water was lower after higher rainfall events. These observations corresponded with the results of fecal coliform analyses with sea water samples. According to the evaluation of the influences of inland pollution sources and fecal coliform analyses on sea water and shellfish samples in Geoje Bay, pollutants from inland sources did not reach the boundary line of the shellfish growing area after rainfall events of 15 or 22 mm. The bacteriological water quality of the shellfish growing area in Geoje Bay met the Korean standard and US NSSP requirements for approved shellfish growing areas.Key words: Geoje Bay, Oyster, Fecal coliform, Shellfish growing area, Inland pollution source

The impact of rainfall events on the sanitary indicator bacteria density of the shellfish-growing waters in Geoje Bay and Jaran Bay in Korea was investigated. The shellfish-growing area in Geoje Bay, which is a nearly closed basin, was not affected significantly, except near the stream mouth after 11.5 mm of rainfall in 1 day. However, most of the shellfish-growing water in the bay was polluted by fecal coliform bacteria after rain as heavy as 43.0 mm, and the levels of fecal indicator bacteria in some of the sea near the coast did not recover completely until 24 hours after the rainfall. By contrast, in Jaran Bay, which has no significant pollution source in the drainage area, although 9.3-490 MPN/100 mL of fecal coliform bacteria were detected near the stream mouth after rainfall of 33.5 and 81.0 mm, a very low level of the indicator bacteria was detected in the designated shellfish-growing area. During the investigation, the correlations between the sanitary indicator bacteria density and physical parameters, such as salinity and turbidity, were evaluated. Both the total coliform and fecal coliform densities were inversely correlated with salinity. Turbidity was positively correlated with the indicator bacteria density. The survey results suggest that for more efficient management of the shellfish-growing areas located in coastal areas, such as shellfish harvesting after rainfall, a detailed investigation of the effects of rainfall on the bacterial water quality in each growing area is needed.

In Hansan Geojeman area, 2,050 ha of shellfish growing area has been designated as shellfish production area for export. The main shellfish species from the designated area is oysters. For the sanitary management of the designated area established in Hansan Geojeman area, bacteriological examination of sea water and shellfish at the sampling stations inside and outside of the designated area were performed from January 2006 to December 2008. The range of fecal coliform of 756 sea water samples at 21 stations located in the designated area were 1,600 MPN/100mL. And the range of geometric mean and the estimated 90th percentile of fecal coliform were 1.8~2.9 and 2.7~15.8 MPN/100mL, respectively. Sanitary conditions of the current designated area in Hansan Geojeman meets the required standards of the Fisheries Product Quality Control and National Shellfish Sanitation Program (NSSP, USA) criteria for the approved area. Also, the sanitary status of the shellfish harvested from the designated area met the Korean Shellfish Sanitation Program (KSSP) fecal coliform criterion (

【Bacteriological examination of a 12,700 ha area within Jaranman Saryangdo area, located in Jaran bay and Saryangdo island, was conducted with 35 fixed (designated areas and adjacent areas) seawater sampling stations between January 2006 and December 2008. According to results, the geometric mean range and the estimated 90th percentile range of fecal coliform counts in sea water samples collected in the designated area were】

Antimicrobial resistance patterns of Vibrio species isolated from brackish water in Geoje, Tongyeong and Goseong, Gyeongsangnamdo province into which streams, sewage and leachate all flowed. Only 19 strains (10.7%) of 177 V. parahaemolyticus were susceptible to 15 antimicrobials. 146 strains (69.5%) proved resistant against more than one antimicrobial and 12 strains (6.8%) were multi-drug resistant. The resistance rate of 152 strains were 85.9% against AM and 26.6% against RA, 16.4% against AN, 13.6% against Sand 13.0% against TMP. 86 strains of 129 V. cholerae non-O1 (66.7%) were susceptible to antimicrobials and 31 strains (24.0%) were resistant to more than one antimicrobial and 12 strains (9.3%) were multi-drug resistant. The antimicrobial resistance rate of 129 strains against 15 antimicrobials, with the exception of C, CIP, E and GM, i.e. 11 antimicrobials, was 0.7-16.2%, 16.2% of 129 strains proved resistant against RA and 13.9% against AM, 9.3% against TMP, 7.7% against SXT and 6.9% against TE. 19 of 49 strains of V. mimicus (38.8%) were susceptible to antimicrobials and 31 strains (61.2%) were resistant against more than one antimicrobial; none of the strains were multi-drug resistant. 15 strains of V. mimicus were resistant against only RA, AmC and TE. The resistance rate was 59.2% against RA (highest) 4.1% against AmC and 2.0% against TE.

Heavy metal complexations with host molecules have been received much attention, not only because of prime environmental concern, but also the heavy metal binding is one of fundamental problems of molecular recognition. Based on the optimal requirement of cooperative effect of the mixed coordinating sites via thiaoxa donor set for heavy metals, we have reported the solvent extraction, membrane transport and crystal structures of Ag and Pd complexes with the new system of the cyclic and acyclic ionophores incorporating a potential thiaoxa donor system. Particularly, the acyclic thiaoxa ionophores can be obtained simply and cheaply because there is no need for expensive and timeconsuming steps, such as high dilution or template methods, which is usually required in preparations of cyclic analogues. In the continuing work on the metal complexation, we were recently able to prepare the new Hg complex of the S2O2 dipodal ligand L and have determined its X-ray crystal structure. Although the stability constant for the Hg complex with L is not yet available, this result is enough to motivate the works on the stripping voltammetry by using the modified carbon paste electrode (CPE) as a more sophisticated detection procedure for Hg. Herein, we describe the preparation of the Hg complex of L together with its crystal structure. In addition, the characteristics of the L-modified CPEs are presented in terms of the Hg detection.

An amperometric biosensor based on carbon paste electrodes (CPEs) for the determination of urea was constructed by enzyme (urease/GL-DH)-modified method. Urea was hydrolyzed to NH4 + by catalyzing urease onto the enzyme-modified electrode surface in sample solution. In the presence of α -ketoglutarate and reduced nicotinamide adenine dinucleotide(NADH), a liberated NH4 + produce to L-glutamate and NAD + by Lglutamate dehydrogenase (GL-DH). After the chemical reaction was proceeded, the electrochemical reaction was occurred that an excess of the NADH was oxidized to NAD + . The oxidation current of NADH was monitored at +1.10 volt vs. Ag/AgCl. An optimum conditions of biosensor were investigated: The optimum pH range for catalyzed hydrolysis reaction of urea was pH 7.0-7.4. The linear response range and detection limit were 2.0 × 10 −5 ~2.0 × 10 −4 M and 5.0 × 10 −6 M, respectively. Another physiological species did not interfere

From 2009 to 2013, 80 oyster and 16 seawater samples were collected from the southern coast of Korea, including designated shellfish growing areas for export. The concentrations and bioaccumulation of heavy metals were determined, and a potential risk assessment was conducted to evaluate their hazards towards human consumption. The cadmium (Cd) concentration in oysters was the highest of three hazardous metals, including Cd, lead (Pb), and mercury (Hg), however, below the standards set by various countries. The metal bioaccumulation ratio in oysters was relatively high for zinc and Cd but low for Hg, Pb, arsenic, and chromium. The estimated dietary intakes of all heavy metals for oysters accounted for 0.02%-17.75% of provisional tolerable daily intake. The hazard index for all samples was far

Chemically modified electrodes for Ag(I) ion determination were constructed by incorporating S2O2-donor podand, L1 with a carbon paste mixture composed of graphite powder. Ag(I) ion was chemically deposited onto the surface of the modified electrode and then reduced at -0.4 V vs. Ag/AgCl. Well-defined stripping voltammetric peak was obtained by scanning the potential to the positive direction. By differential pulse stripping voltammetry, the appropriate calibration graph for Ag(I) was obtained between 5.0 × 10-7 M and 1.5 × 10-6 M and detection limit was 2.0 × 10-7 M. The ionic species such as Cd(II), Cu(II), Zn(II), Hg(II), EDTA, and oxalate(II) did not influence the determination of Ag(I) ion, except Pb(II).

An immunochromatography (ICG) strip test based on a monoclonal antibody for the rapid detection of L. monocytogenes in meat and processed-meat samples was developed in this study. A monoclonal antibody (MAb) specific to L. monocytogenes was produced from cloned hybridoma cells (FKLM-3B12-37) and used to develop an ICG strip test. The antibody showed a stronger binding to L. monocytogenes than other Listeria species, and a weak cross-reaction to S. aureus based on an ELISA. The detection limit of the ICG strip test was 10(5) cell/ml. In total, 116 meat and processed-meat samples were collected and analyzed using both the ICG strip test and a PCR. The ICG strip test and PCR indicated L. monocytogenes contamination in 34 and 27 meat samples, respectively. The 7 meat samples not identified as L. monocytogenes positive by the PCR were also tested using an API kit and found to be contaminated by Listeria species. In conclusion, the ICG strip test results agreed well with those obtained using the PCR and API kit. Thus, the developed ICG has potential use as a primary screening tool for L. monocytogenes in various foods and agricultural products, generating results within 20 min without complicated steps.

A total of 50 raw milk samples from Gyeongnam Province of Korea were examined for the incidence of Listeria monocytogenes between July 1998 and August 1998. L. monocytogenes isolated by biochemical test was confirmed by polymerase chain reaction (PCR) with two sets of primers designed from the invasion-associated protein (iap) gene. After standard PCR with external primers, the amplified DNA was confirmed by a second round of PCR with internal primers (nested PCR). Both the external and internal primers generated 468-bp and 287-bp products, respectively. Only one (G9 strain) of the three suspect samples that tested positive in biochemical tests for L. monocytogenes from 50 raw milk samples was also PCR positive. Following this procedure, PCR-positive G9 strain was confirmed by Southern blot using the 287-bp internal iap probe again. The detection limit of G9 strain by standard PCR assay was as few as 10 2 cells, equivalent to approximately I pg of L. monocytogenes DNA. These PCR assays may be useful for novel detection as well as rapid confirmation for L. monocytogenes from food samples and the field. 50 laits crus ont ete analyses entre juillet et aout 1998. Listeria monocytogenes est isolee et testee par PCR. 2 amorces correspondant au gene iap sont utilisees. 2 PCR sont effectuees. 1 echantillon est teste positif par PCR. La limite de detection par PCR est 10 2 cellules soit 1pg de DNA de L.monocytogenes. Cette methode est sensible et rapide.

From 2011 to 2013, we conducted a full sanitary survey of pollution sources in proximity to a shellfish growing area in the Hansan-Geojeman region in Korea, which includes a designated shellfish growing area. In the sea area, 1152 seawater and 209 oyster samples were collected and examined to evaluate their bacteriological quality. There were 758 potential pollution sources in the drainage area, including 40 sources discharging water in 2013. Fecal coliform (FC) concentrations and impact radii of discharges ranged from 1.8 to 700,000 MPN/100 mL and from 3 to 600 m, respectively; however, the pollutants did not reach the designated area. This demonstrates that the dilution of waste was sufficient such that no significant impact occurred within the designated shellfish growing area. The variation in the FC levels of seawater was closely related to season and rainfall. The FC levels of seawater and oysters from the designated area met the regulation limits set by various countries. No pathogens were found in any oysters. The results of the survey indicate that the oysters produced in this area are apparently safe for raw consumption based on their bacterial quality.