• Journal of Life Science
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• v.32 no.1
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• pp.36-43
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• 2022

Mucosal immunity is a well-designed defense system that builds precise and dynamic relationships against pathogens, and the gastrointestinal tract is the most important organ with this system, acting as a guardian at the forefront of its activity. Salmonella spp. cause food poisoning, entering the body orally and mainly invading the Peyer's patches of the small intestine. Although Salmonella strains share similar mechanisms for inducing innate immunity, different serotypes may have different effects on the intestinal mucosa due to host specificities and pathogenicity. In this study, we evaluated the effects of Salmonella enteritidis infections in mouse intestine and observed significantly reduced dose-dependent survival rates in a challenge test. Flow cytometry data showed no significant differences in intestinal immune cell populations, although histology indicated increased mucin production and decreased goblet cell counts in the Salmonella-treated groups. Furthermore, Claudin expression was significantly decreased in the samples with Salmonella. To investigate the relationship between S. enteritidis infection and inflammatory response, dextran sodium sulfate (DSS) was administered after infection and the results indicate lower survival rate after DSS treatment. In conclusion, we were able to identify the optimal concentration of S. enteritidis to modulate the intestinal mucosal immunity of mice and inflammatory response.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.896-903
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• 2021

For the safety assessment of microbiological and chemical hazards in raw short-neck clam Ruditapes philippinarum distributed in the Yeongnam and Honam areas during the spring season, the contamination levels of total viable bacteria, coliforms, Escherichia coli, and nine pathogenic bacteria (Staphylococcus aureus, Salmonella spp., Vibrio parahaemolyticus, Clostridium perfringens, Listeria monocytogenes, enterohemorrhagic Escherichia coli, Yersinia enterocolitica, Bacillus cereus, Campylobacter jejuni) as microbiological hazards, and heavy metals (lead, cadmium, total mercury), benzopyrene, shellfish poison (paralytic, diarrhetic, amnesic), and radioactivity (¹³¹I, ¹³⁴Cs+¹³⁷Cs) were also analyzed in 15 samples based on the methods of the Korean Food Code. The average contamination levels of total viable bacteria were 3.11 (1.40-4.49) log CFU/g, and coliforms were detected in 5 out of 15 samples (1.18-1.85 log CFU/g). E. coli and S. aureus were not detected in all samples. Furthermore, the presence of 8 pathogens were not detected in all samples. The average contamination levels of lead, cadmium, and total mercury were 0.155 (0.079-0.264), 0.160 (0.040-0.287), and 0.017 (0.008-0.026) mg/kg, respectively. Benzo(a)pyrene, shellfish poison, and radioactivity were not detected in all samples. The results of this study suggest that the safety against all microbiological and chemical hazard factors in raw short-neck clams distributed in markets has been assured.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.1
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• pp.83-93
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• 2021

Objectives: 'Confined space' was only defined in the Safety and Health Regulations as a place where oxygen deficiency and hydrogen sulfide must be dealt with at the time of the initial enactment (1982). The danger of fire and explosion were added in 2003. We will compare and review the regulations related to confined space work under the current safety and health rules alongside regulations in other countries and prepare a plan to improve the system through enhanced clarity and execution. Methods: In a comparison of systems for the prevention of suffocation in confined spaces in major countries (Germany, United States, Japan) different concepts of the definition of confined spaces in different countries apparently due to differences in each country's legal implementation system, accident analysis methods, the status of safety and health implementation in workplaces, the precautions against actual confined space work, and the definition of confined spaces were found to be not much different between Korea and the other foreign countries. Results: In the case of Germany and the United States, a confined space is defined as a contextual concept rather than a place, so more careful attention is needed from operators or enclosed space managers as it is often necessary to judge the actual workplace. In the case of Korea and Japan, the interior of the place is mainly defined as a place, especially in the case of Japan, which concentrates on oxygen deficiency and hydrogen sulfide poisoning. Conclusions: For measures to improve regulations on the prevention of suffocation accidents in Korea, I would like to propose three major measures to improve the system in the rules on domestic industrial safety and health standards. It is necessary to prepare and provide a guide to ensure that the 18 types of confined spaces currently defined as confined spaces are clearly understood by field management supervisors or workers.

• Journal of The Korean Society of Clinical Toxicology
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• v.19 no.2
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• pp.83-92
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• 2021

Purpose: Glyphosate herbicide (GH) is a widely used herbicide and has been associated with significant mortality as poisoned cases increases. One of the reasons for high toxicity is thought to be toxic effect of its ingredient with glyphosate. This study was designed to determine differences in the clinical course with the salt-type contained in GH. Methods: This was a retrospective study conducted at a single hospital between January 2013 and December 2017. We enrolled GH-poisoned patients visited the emergency department. According to salt-type, patients were divided into 4 groups: isopropylamine (IPA), ammonium (Am), potassium (Po), and mixed salts (Mi) groups. The demographics, laboratory variables, complications, and their mortality were analyzed to determine clinical differences associated with each salt-type. Addtionally, we subdivided patients into survivor and non-survivor groups for investigating predictive factors for the mortality. Results: Total of 348 GH-poisoned patients were divided as follows: IPA 248, Am 41, Po 10, and Mi 49 patients. There was no difference in demographic or underlying disease history, but systolic blood pressure (SBP) was low in Po group. The ratio of intentional ingestion was higher in Po and Mi groups. Metabolic acidosis and relatively high lactate level were presented in Po group. As the primary outcome, the mortality rates were as follows: IPA, 26 (10.5%); Am, 2 (4.9%); Po, 1 (10%); and Mi, 1 (2%). There was no statistically significant difference in the mortality and the incidence of complications. Additionally, age, low SBP, low pH, corrected QT (QTc) prolongation, and respiratory failure requiring mechanical ventilation were analyzed as independent predictors for mortality in a regression analysis. Conclusion: There was no statistical difference in their complications and the mortality across the GH-salt groups in this study.

• Korean Journal of Veterinary Service
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• v.45 no.3
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• pp.155-164
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• 2022

This study was conducted for safety evaluation on 130 pet food products, which are distributed in Gwangju, South Korea. The microbial contamination part and the usage of food additives part were mainly investigated. The five microorganisms that we tested were total viable cell counts (TVC), Coliforms, Salmonella spp., Campylobacter spp., pathogenic Escherichia coli and there were 15 products that exceed the microbial criteria or detected food poisoning bacteria. Specifically, Coliforms (13 products, 10%), TVC (9 products, 6.9%), Salmonella spp. (2 products, 1.5%), and E. coli (2 products, 1.5%) were followed. On the other hand, food additives such as preservatives, antioxidants and sodium nitrite were detected in 61 products. Among the preservatives, sorbic acid and benzoic acid were detected in 58 (44.6%) products. In antioxidants, Butylated hydroxytoluene (BHT) was detected in 3 (2.3%) products. In addition, preservatives and antioxidants were detected in 8 of 20 products labeled as 'additive-free'. Microbial contamination tended to occur mainly in small-scale individual homemade feed stores, while food additives were all detected in pet shops and supermarkets. Currently, the criteria for microorganisms and food additives for pet foods are insufficient in Korea. So, it is necessary to establish detailed feed standards and specifications for companion animals.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.866-873
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• 2022

Growth rate and production of the paralytic shellfish poisoning toxin (PST) of a toxic dinoflagellate Alexandrium pacificum (LIMS-PS-2611) isolated from the southern sea of Korea, were examined under various temperatures and salinity conditions. The maximum growth rate (0.28 day^-1) was observed under 25℃ and 30 psu. Optimal growth (≥ 70% of maximum growth rate) was obtained between 20~25℃ and 25~35 psu. Among the PSTs of A. pacificum, the principal toxins were C1+2 and GTX5 in N-sulfocarbamoyl toxin group, and minor components were characterized as neoSTXs in the carbamate toxin group. Maximum toxin content was observed under 20℃ and 30 psu, and the toxin content increased with the increase of salinity. Low toxin contents were measured under the temperature and salinity conditions of the maximum growth rate. Therefore, the PSP of bivalve, which occurs at a temperature range of 20-25℃ in June, might have been derived from A. pacificum.

• Journal of Food Hygiene and Safety
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• v.37 no.4
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• pp.232-237
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• 2022

The present study investigated the bactericidal effects of chlorine dioxide (CD) and electrolyzed water (EW) on pathogenic bacteria, such as Bacillus cereus, Staphylococcus aureus, Salmonella Typhimurium, and Escherichia coli O157:H7, by treatment them with CD and EW, respectively, for 0, 2, 4, 6, 8, and 10 min. Additionally, the sensitivities of Gram-positive (B. cereus and S. aureus) and Gram-negative (S. Typhimurium and E. coli O157:H7) to CD and EW were compared, respectively. In CD, the D-values for B. cereus, S. aureus, S. Typhimurium, and E. coli O157:H7 were 1.85±0.64, 2.06±0.85, 2.26±0.89, and 2.59±0.40 min, respectively. In EW, the D-values for B. cereus, S. aureus, S. Typhimurium, and E. coli O157:H7 were 2.13±0.32, 1.64±0.64, 1.71±0.32, and 1.86±0.36 min, respectively. All strains decreased consistently for 10 min in both CD and EW. However, the D-values of each bacterial species did not differ significantly between CD and EW (P>0.05). When comparing the bactericidal effect of CD and EW, no difference in D-value was observed, even though the pH and available chlorine concentration of CD were significantly lower than those of EW. These data could be used for the application of CD and EW in the food industry, considering characteristics such as the selection of optimal disinfectants, determination of optimal concentrations, and sensitivity to disinfection targets.

• Journal of The Korean Society of Clinical Toxicology
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• v.20 no.1
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• pp.1-7
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• 2022

Purpose: In patients with acute drug overdose, identification of drugs ingested is crucial to make a precise diagnosis. In most cases, the diagnoses are made on the medical history and physical examination findings. This study was undertaken to determine the concordance of diagnosis made on the basis of patient history by comparing it with urine toxicology analysis. Methods: This was a retrospective study of drug intoxicated patients over 18 years old who presented to the emergency center from 2017 to 2019. Specimens from urine were tested using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-TMS). The test results were compared with information obtained from patients. Diagnostic concordances for drug detection in intoxicated patients were calculated. Logistic regression analysis was used to examine the association between clinical characteristics and diagnostic discrepancy. Results: Totally, 370 patients were included in the analysis. Overall, 66 types of drugs were detected by UPLC-TMS. The drugs detected most frequently were zolpidem (104, 27.8%), citalopram (70, 18.7%), and paracetamol (66, 17.6%). The mean diagnostic concordance of patients was 52.7%. There were statistically significant diagnostic discrepancies in patients with underlying depression and patients intoxicated with multiple types of drugs. Conclusion: In ED patients with acute drug overdose, the diagnoses made on history alone were often inaccurate. It is essential to perform urine toxicology tests such as UPLC-TMS as a confirmatory instrument to improve accuracy in evaluating patients with drug intoxication.

• Membrane Journal
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• v.32 no.6
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• pp.442-455
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• 2022

High-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) has been studied as an alternative to low-temperature PEMFC due to its fast activation of electrodes and high resistance to electrode poisoning by carbon monoxide. It is highly required to develop stable PEMs operating at high temperatures even doped by ion-conducting materials for the development of high-performance and durable HT-PEMFC systems. A number of studies have been conducted to develop polybenzimidazole (PBI)-based PEMs for applications in HT-PEMFC due to their high interaction with doped ion-conducting materials and outstanding thermomechanical stability under high-temperature operation. This review focused on the development of PBI-based PEMs showing high performance and durability. Firstly, the characteristic behavior of PBI-based PEMs doped with various ion-conducting materials including phosphoric acid was systematically investigated. And then, a comparison of the physicochemical properties of the PEMs according to the different membrane manufacturing processes was conducted. Secondly, the incorporation of porous polytetrafluoroethylene substrate and/or inorganic composites to PBI matrix to improve the membrane performances was studied. Finally, the construction of cross-linked structures into PBI-based PEM systems by polymer blending method was introduced to improve the PEM properties.

• Journal of Food Hygiene and Safety
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• v.38 no.4
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• pp.246-254
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• 2023

V. parahaemolyticus causes waterborne and foodborne disease such as acute diarrhea. In this study, V. parahaemolyticus isolates from seawater, fish tanks, and distributed fishery products in Jeju were investigated for potential toxin or species-specific genes (tdh, trh, tlh, and toxR) using RT-PCR and their genetic characteristics were analyzed using Pulsed-field gel electrophoresis (PFGE). Overall, V. parahaemolyticus of 90 strains (36.7%), including 33 strains from seawater, 8 strains from fish tanks, and 50 strains from fishery products, were isolated from 245 samples. All V. parahaemolyticus strains did not detect the tdh gene, whereas all strains detected tlh or toxR genes. In addition, trh genes were detected in 3 strains from seawater and 1 strain from fishery products. Monthly quantitative testing of seawater revealed that V. parahaemolyticus was positively correlated with water temperature. The 90 strains of V. parahemolyticus obtained in this study showed by gene homology between types, ranging from 64.0-97.3%. Among these, thirteen types showed 100% homology between genes. These results indicate that continuous monitoring is needed to facilitate food poisoning epidemiological investigations because some isolated V. parahaemolyticus strains harbored toxin genes and V. parahaemolyticus strains isolated from seawater, fish tanks, and distributed fishery products showed genetic similarity.