• 한국수산과학회지
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• 제54권6호
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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.

• 한국수산과학회지
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• 제54권6호
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• pp.904-911
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• 2021

For the safety assessment of microbiological and chemical hazards in dried sea mustard, fifteen samples of dried sea mustards Undaria pinnatifida were purchased from the supermarkets distributed throughout Korea. The contamination levels of total viable bacteria, coliforms, Escherichia coli, and nine pathogenic bacteria [Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, Bacillus cereus, Vibrio spp., Clostridium perfringens, Enterohemorrhagic Escherichia coli (EHEC), Yersinia enterocolitica and Campylobacter jejuni/coli] were quantitatively or qualitatively assessed. Also, the heavy metals (lead, cadmium, total mercury, and inorganic arsenic), and radioactivity (¹³¹I, ¹³⁴CS+¹³⁷CS) were quantitatively assessed. This microbial and chemical analysis was performed using standard methods in Korean food code. The total viable bacteria ranged from 4.3×10² (5.0×10-1.5×10³) CFU/g. Coliforms and E. coli were not detected in all samples (ND, <1 log₁₀ CFU/g). All nine pathogenic bacteria were qualitatively detected as negative. The contamination levels of lead, cadmium, total mercury, and inorganic arsenic were 0.036 (0.015-0.051), 0.117 (0.088-0.156), 0.030 (0.017-0.048), and 0.058 (0.056-0.064) mg/kg, respectively. Radioactivity was also not detected in any sample. The microbial contamination levels determined in the current study may be potentially used as basis for performing microbial risk assessments of dried sea mustards.

• 한국식품위생안전성학회지
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• 제37권5호
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• pp.356-363
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• 2022

감귤류 종류에 따른 과피의 생리활성을 조사하기 위해 mandarin, lemon, orange, grapefruit 과피 분말을 시료로 하여 70% ethanol 추출물을 제조한 후 산화방지 성분 및 활성과 식중독 세균 억제 활성을 측정하였다. Mandarin 과피는 총 페놀화합물과 총 플라보노이드 물질을 각각 21.46±0.12 mg GAE/g, 11.57±0.05 mg RE/g으로 가장 많이 함유하고 있었다. Mandarin 이외 3종의 감귤류 과피의 총 페놀화합물 함량은 14.16±0.18-18.44±0.07 이었으며, 총 플라보노이드 함량은 5.51±0.10-7.46±0.09 mg RE/g으로 나타났다. 산화방지 활성을 측정한 결과 lemon 과피의 DPPH 라디칼 소거능이 가장 높은 87.64±0.21%를 나타냈으며, ABTS 라디칼 소거능과 FRAP 측정 결과 mandarin 과피가 각각 43.20±0.61%, 78.82±1.06 mM TE/g으로 가장 우수한 산화방지 활성을 가지는 것으로 나타났다. 식중독 세균 억제 활성 시험에서 grapefruit 과피는 처리 시간이 경과함에 따라 억제 활성이 증가했으며 S. aureus를 4.05 log cfu/mL 정도 억제하여 4종의 감귤류 중 식중독 세균 억제 활성이 가장 뛰어났다. 본 연구 결과에 따라, 감귤류 중 mandarin과 grapefruit 과피는 산화방지 및 식중독 세균 억제 등 식품의 저장성을 향상시킬 목적으로 사용될 수 있으며 이에 따라 품질보존료로서 잠재적 가능성이 높다고 생각된다.

• Journal of Veterinary Science
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• 제23권6호
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• pp.12.01-12.10
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• 2022

Background: Staphylococcus aureus and Streptococcus agalactiae are the main cause of clinical mastitis in dairy cattle in Argentina, whereas coagulase-negative staphylococci (CNS) and environmental streptococci are the main cause of subclinical mastitis. Bacteria isolated from infected animals show increasing antimicrobial resistance. Objectives: This study aims to determine the antimicrobial resistance of staphylococci and streptococci isolated from milk with mastitis, and to genotypically characterize the methicillin-resistant (MR) staphylococci. Methods: Isolation was performed on blood agar and identification was based on biochemical reactions. Antimicrobial susceptibility was according to the Clinical and Laboratory Standards Institute guidelines. The antimicrobial resistance genes, SCCmec type and spa type were detected by the polymerase chain reaction method. Results: We isolated a total of 185 staphylococci and 28 streptococci from 148 milk samples. Among the staphylococcal isolates, 154 were identified as CNS and 31 as S. aureus. Among the 154 CNS, 24.6% (n = 38) were resistant to penicillin, 14.9% (n = 23) to erythromycin, 17.5% (n = 27) to clindamycin, 6.5% (n = 10) to cefoxitin and oxacillin. Among the S. aureus isolates, 16.1% (n = 5) were resistant to penicillin, 3.2% (n = 1) to cefoxitin and oxacillin (MRSA). Six MR isolates (5 CNS and 1 MRSA) were positive to the mecA gene, and presented the SCCmec IVa. The MRSA strain presented the sequence type 83 and the spa type 002. Among the 28 streptococcal isolates, 14.3% (n = 4) were resistant to penicillin, 10.7% (n = 3) to erythromycin and 14.3% (n = 4) to clindamycin. Conclusions: The present findings of this study indicate a development of antimicrobial resistance in main bacteria isolated from cows with mastitis in Argentina.

• 한국수산과학회지
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• 제56권2호
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• pp.182-187
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• 2023

Fifteen samples of dried laver Pyropia tenera were collected from markets and processing plants in Korea for an assessment of their microbial and chemical hazards, in accordance with the Korean food code. The contamination levels of total viable bacteria, coliforms, Escherichia coli, and nine other pathogenic bacteria (Staphylococcus aureus, Salmonella spp., Vibrio parahaemolyticus, Clostridium perfringens, Listeria monocytogenes, Enterohemorrhagic Escherichia coli, Yersinia enterocolitica, Bacillus cereus, and Campylobacter jejuni) were evaluated The concentrations of heavy metals (lead, cadmium, total mercury, and total arsenic) and radioactive isotopes (¹³¹I, and ¹³⁴Cs+¹³⁷Cs) in the laver samples were also determined. The total viable count of bacteria was 2.62±0.80 (1.48-4.45) CFU/g. The contamination levels of lead, cadmium, total mercury, and total arsenic were 0.024±0.005 (0.018-0.035), 0.090±0.038 (0.041-0.146), 0.008±0.005 (0.003-0.018) and 1.315±0.372 (0.814-1.930) mg/kg, respectively. All samples tested negative for significant levels of radioactivity, the nine pathogenic bacteria, coliforms, and E. coli (<1.00 CFU/g). We assume that ensuring the microbiological and chemical safety of dried laver can increase the demand for its exportation. The present study may serve as a basis for microbiological and chemical hazard assessment of dried lavers.

• 한국식품영양학회지
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• 제36권1호
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• pp.33-41
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• 2023

To increase antioxidant and antibacterial activities of seasoned soy sauce, five kinds of oriental medicinal plant(Scutellaria baicalensis (P1), Coptis japonica makino (P2), Citriunshius pericarpium (P3), Zizyphi spinosi semen (P4), Crataegus pinnatifida(P5)) and four kinds of medicinal mushrooms(Inonotus obliquus (M1), Hericium erinaceus (M2), Phellinus linteus (M3), Lentinula edodes(M4)) were added to seasoned soy sauce. Soluble solid content, pH, salinity, total polyphenol & flavonoid contents were determined. DPPH & ABTS radical scavenging activities, SOD-like activity, and antibacterial activity were analyzed. Experimental sauces showed decreased pH but significant increases of soluble solid content and salinity. Total polyphenol content was 12.76 ㎍ GAE/g in the control. However, M1 and P1 sauce had significantly higher polyphenol contents at 352.14 and 528.25 ㎍ GAE/g, respectively. Total flavonoids content also showed the same pattern. DPPH free radical scavenging activity was the lowest in the control at 15.75%. It was the highest at 81.80% in M1 and 68.88% in P1. ABTS free radical scavenging activity and SOD-like activity showed the same tendencies. They were higher in the experimental groups than in the control. As for the antibacterial activity analyzed by the paper-disc method, the activity increased the most in P1 and P2. In particular, P2 had the strongest antibacterial activity. Its activity against different microorganisms was in the order of Staphylococcus aureus > Bacillus cereus > Escherichia coli > Salmonella typhimurium. In conclusion, these new sauces show increased antioxidative and antioxidant activities. Therefore, they are expected to be used in various ways as a functional soy sauce.

• Fisheries and Aquatic Sciences
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• 제25권11호
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• pp.579-586
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• 2022

Research on the potential biological activity of red alga Symphyocladia spp. has been limited to Symphyocladia latiuscula, which is widely used as a food ingredient in Korea. Here, we examined the biological activity of another species, Symphyocladia linearis, which is found in Korea and was reported as a new species in 2013. The aim of this study was to evaluate the antioxidant, anti-inflammatory, and antibacterial properties of a 70% ethanol extract of S. linearis. Antioxidant activity, which was evaluated using radical scavenging assays, revealed half maximal inhibitory concentration values for 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) of 34.57 and 11.70 ㎍/mL algal extract, respectively. Anti-inflammatory activity of the S. linearis ethanolic extract was evaluated using RAW 264.7 cells by measuring the inhibition of lipopolysaccharide-induced nitric oxide (NO) and prostaglandin E₂ (PGE₂) production. The potential cytotoxicity of NO and PGE₂ was first examined, confirming no toxicity at concentrations ranging from 10-100 ㎍/mL. NO production was inhibited 61.1% and 78.0% at 50 and 100 ㎍/mL S. linearis extract, respectively; and PGE₂ production was inhibited 69.1%, 83.2%, and 94.8% at 25, 50, and 100 ㎍/mL S. linearis extract, respectively. Thus, the S. linearis extract showed very strong efficacy against PGE₂ production. The cellular production of reactive oxygen species, measured using 2',7'-dichlorofluorescin diacetate fluorescence, was inhibited 48.8% by the addition of 100 ㎍/mL S. linearis extract. Antibacterial activity was evaluated using the disc diffusion method and minimum inhibitory concentration (MIC). S. linearis was effective only against gram-positive bacteria, exhibiting antibacterial activity against Staphylococcus aureus with a MIC of 256 ㎍/mL extract and against Bacillus cereus with a MIC of 1,024 ㎍/mL extract. Based on these results, we infer that a 70% ethanolic extract of S. linearis possesses strong anti-inflammatory properties, and therefore has the potential to be used in the prevention and treatment of inflammatory and immune diseases.

• 한국포장학회지
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• 제29권2호
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• pp.79-86
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• 2023

최근 플라스틱 포장 폐기물 및 굴 패각이 야기하는 환경문제와 장기간 식품의 품질 보존을 위한 액티브 패키징이 주목받고 있다. 이에 따라 본 연구에서는 PLA/PBAT 복합필름에 OSP의 함량을 서로 달리하여 이축 압출기로 PLA/PBAT-OSP 복합필름을 제조하였고 항균 포장재로써 적용가능성을 확인하였다. 이를 위해 화학적 특성, 표면 특성, 열적 특성, 기계적 특성 및 항균성을 평가하여 분석하였다. PLA/PBAT-OSP 복합필름의 고분자 매트릭스 내에서 OSP의 물리적 분산을 확인하였으며, OSP의 함량이 증가함에 따라 항균성이 증가하였다. 특히 OSP 5%, OSP 10% 필름에서는 99% 이상의 항균성을 나타내어 제조된 필름이 우수한 항균성을 가진다는 것을 확인할 수 있었다. 그러나 OSP의 함량의 증가는 PLA/PBAT-OSP 매트릭스 내의 OSP 응집을 일으켜 기계적 물성의 저하 및 표면의 거칠기 증가가 나타났으며, 이는 필름의 표면 에너지 증가로 이어졌다. 결론적으로 PLA/PBAT-OSP 복합필름은 미생물로 인한 식품의 부패를 막기 위한 포장재로 적용될 수 있지만, 이를 위해 OSP의 분산성과 필름의 기계적 물성을 향상시키기 위한 추가 연구가 필요할 것으로 보인다.

• Journal of Microbiology and Biotechnology
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• 제33권2호
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• pp.219-227
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• 2023

Lettuce is one of the most consumed vegetables worldwide. However, it has potential risks associated with pathogenic bacterial contamination because it is usually consumed raw. In this study, we investigated the changes in the bacterial community on lettuce (Lactuca sativa L.) in Chungcheong-do, South Korea, and the prevalence of foodborne pathogens on lettuce in different seasons using 16S rRNA gene-based sequencing. Our data revealed that the Shannon diversity index showed the same tendency in term of the number of OTUs, with the index being greatest for summer samples in comparison to other seasons. Moreover, the microbial communities were significantly different between the four seasons. The relative abundance of Actinobacteriota varied according to the season. Family Micrococcaceae was most dominant in all samples except summer, and Rhizobiaceae was predominant in the microbiome of the summer sample. At the genus level, the relative abundance of Bacillus was greatest in spring samples, whereas Pseudomonas was greatest in winter samples. Potential pathogens, such as Staphylococcus and Clostridium, were detected with low relative abundance in all lettuce samples. We also performed metagenome shotgun sequencing analysis on the selected summer and winter samples, which were expected to be contaminated with foodborne pathogens, to support 16S rRNA gene-based sequencing dataset. Moreover, we could detect seasonal biomarkers and microbial association networks of microbiota on lettuce samples. Our results suggest that seasonal characteristics of lettuce microbial communities, which include diverse potential pathogens, can be used as basic data for food safety management to predict and prevent future outbreaks.

• 한국응용곤충학회지
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• 제62권2호
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• pp.95-102
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• 2023

최근 들어 반려동물을 키우는 가구 수가 증가하고 있다. 그로인해 진드기와 냄새에 대한 관심 또한 증가하고 있다. 본 연구는 제충국 추출물(Tanacetum cinerariifolium), 수용성 피톤치드(water-soluble phytoncide)가 진드기 퇴치제로서 효과와 탈취 및 항균 효과가 있는지 알아보기 위하여 연구를 진행하였다. 틱 클라이밍 테스트(Tick climbing test)에서 제충국 추출물(Tanacetum cinerariifolium) 23.33점, 수용성 피톤치드 22.00점으로 높은 기피효과를 보였다. 복합추출물로서의 진드기 기피 효과를 확인하기 위해 위 실험에서 기피 효과가 확인된 제충국 추출물, 수용성 피톤치드를 포함한 복합추출물(Sample이라 함.), 타사 제품(Control이라 함.)로 틱 클라이밍 테스트(Tick climbing test)를 진행하였다. 결과 Sample 13.00점, Control 26.67점으로 Sample이 높은 기피 효과를 나타내었다. 참진드기 실내 기피제 효력 시험법에서도 Sample이 88%, Control이 12%로 우수한 진드기 기피효과를 보인다는 것을 확인하였다. Sample을 가지고 탈취 시험을 진행한 결과 암모니아에서 98.3%, 트리메틸아민에서 99.5%의 탈취 효과를 보여주었으며, 항균시험에서 대장균, 황색포도상구균, 폐렴균 모두 99.9%의 항균 효과를 보여주었다. 본 연구결과를 종합해 볼 때 위 소재를 포함한 복합추출물은 추후 진드기 기피제와 탈취 및 항균에도 효과가 있는 소재로서의 활용 가치가 높다고 판단된다.