• Title/Summary/Keyword: microbial safety

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Evaluation on Microbial Contamination in Red Pepper and Red Pepper Cultivated Soil in Korea (고추와 고추 재배 토양의 미생물 오염도 조사)

  • Jeong, Bo-Reum;Seo, Seung-Mi;Jeon, Hye-Jin;Roh, Eun-jung;Kim, Se-Ri;Lee, Theresa;Ryu, Jae-Gee;Ryu, Kyoung-Yul;Jung, Kyu-Seok
    • Journal of Food Hygiene and Safety
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    • v.33 no.5
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    • pp.347-353
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    • 2018
  • Red pepper is widely used as a spicy flavor ingredient in the food industry and many households. The objective of this study was to assess the total aerobic bacteria count, coliforms count and incidence of Escherichiacoli, Salmonella spp., Escherichiacoli O157:H7, Listeria monocytogenes, and Bacillus cereus in red pepper and red pepper cultivated soil. The total aerobic bacteria number in red pepper and soil were in the range of 2.97 to 8.13 and 5.91 to 7.65 log CFU/g, respectively. The coliforms in red pepper and soil were in the range of 1.87 to 6.71 and 0.67 to 6.16 log CFU/g, respectively. E. coli was detected in 3 of 54 soil samples. In 3 out 63 red pepper and 53 of 54 soil samples, B. cereus was detected, while Salmonella spp., E.coli O157:H7, and L.monocytogenes were not detected. The results from this study provide an important basic information associated with the microbiological safety of fresh vegetables. Continuous caution is needed to prevent the contamination of pathogenic microorganisms during its farming.

Diversity of Mycotoxigenic Fusarium armeniacum Isolated from Rice Grains at Harvest Time in Korea (수확기 벼 이삭에서 분리된 진균독소 생성 Fusarium armeniacum의 다양성)

  • Hong, Sung Kee;Lee, Soohyung;Lee, Theresa;Ham, Hyeonheui;Mun, Hye Yeon;Choi, Hyo Won;Son, Seung-Wan;Ryu, Jae-Gee
    • The Korean Journal of Mycology
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    • v.43 no.3
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    • pp.158-164
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    • 2015
  • A total of 509 rice panicle samples were collected at harvest time from fields in 8 provinces from 2010 to 2014. One hundred five grains per sample were plated on potato dextrose agar and 6,658 Fusarium isolates were obtained; among them, 67 were identified as Fusarium armeniacum by sequencing the translation elongation factor $1{\alpha}$ ($EF-1{\alpha}$) and confirmed by their morphological and cultural characteristics. Considerable variation in conidial size, colony color and $EF-1{\alpha}$ sequences was observed among the fungal isolates. The ability of 24 F. armeniacum isolates to produce T-2 and HT-2 toxin in potato sucrose agar was determined using liquid chromatography-mass spectrometry. Twenty one isolates produced T-2 and HT-2 toxin, resulting in varying toxin levels among the isolates. The results show that Korean isolates of F. armeniacum have diversity with respect to morphological, cultural, genetic, and toxigenic properties.

Stability of pUC-Derived Plasmids with a Fluorescence Marker in Pectobacterium carotovorum subsp. carotovorum and subsp. betavasculorum

  • Hur, Woon-Yung;Roh, Eun-Jung;Oh, Chang-Sik;Han, Man-Wi;Lee, Seung-Don;Kim, Doo-Ho;Heu, Sung-Gi
    • The Plant Pathology Journal
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    • v.25 no.3
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    • pp.286-290
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    • 2009
  • The stability of three different kinds of pUC-derived plasmids, pDsRed, pZsYellow, and pGFPuv, was investigated in Pectobacterium strains to utilize those plasmids as tracers. All three plasmids pDsRed, pZsYellow and pGFPuv showed their specific colors in Pectobacterium strains. Especially, the plasmid pDsRed conferred bright pink colonies on the Pectobacterium strains. When the bacteria lost the plasmid pDsRed, the colonies turned white, suggesting that the plasmid could be a good marker system for Pectobacterium strains on different environmental conditions. The effect of the antibiotic pressure on the stability of the plasmid was different depending on the host bacteria. P. carotovorum subsp. betavasculorum was more sensitive to the antibiotic pressure than P. carotovorum subsp. carotovorum Pcc21. However, temperature change significantly affected plasmid stability on both Pectobacterium strains. Almost all strains lost the plasmids with the shift in temperature from $28^{\circ}C$ to $37^{\circ}C$. Presence of the plasmids did not affect bacterial pathogenicity on their own host plants. Among three plasmids, pZsYellow was not useful as a marker because the yellow fluorescent proteins from pZs Yellow were interfered with the yellow natural fluorescence of the plant tissues induced by the defense system. Since the red color of DsRed can be seen with naked eyes, plasmid pDsRed was applicable as a marker. However, the color change was slow so that additional manipulation to increase the expression speed was necessary. Plasmid pGFPuv could serve as a perfect marker without any problem, tracing the reproduction and spread of the plant pathogens perfectly.

Microbial Contamination Levels of Strawberries at Domestic Farms of South Korea

  • Kim, Won-Il;Jo, A-Ra;Kim, Se-Ri;Ryu, Song Hee;Nam, Ki-Woong;Yoon, Yohan;Yoon, Deok-Hoon;Oh, So-Yong;Nam, Myeong Hyeon;Ryu, Jae-Gee;Kim, Hwang-Yong
    • Korean Journal of Soil Science and Fertilizer
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    • v.47 no.6
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    • pp.437-442
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    • 2014
  • Foodborne illness due to the consumption of contaminated raw strawberries is a continuing food safety concern. This study investigated and evaluated contamination levels of bacteria on strawberries at farms stage to evaluate potential hazards associated with fresh strawberries. A total of 315 samples, 105 samples from 5 sampling sites (A to E) of 21 farms and 210 samples from 1 sampling site of 6 farms, was collected every month for four months and analyzed to enumerate aerobic bacterial counts, Coliforms/E. coli, Bacillus cereus and Staphylococcus aureus. In addition, the prevalence study of five pathogens (S. aureus, E. coli, E. coli O157:H7, Salmonella spp. and Listeria monocytogenes) was performed on each sample. Aerobic bacterial counts ranged from 0.48 to 6.36 Log CFU/g, with the highest bacterial cell counts recorded for D and E sites. Coliforms were detected in 71 samples (22.5%) with a minimum of 0.48 cfu/g and a maximum of more than 4 Log CFU/g. B. cereus was detected in 98 samples (31.1%) among total samples analyzed. S. aureus was detected in 2 samples with a minimum of 0.48 Log CFU/g and a maximum of 1.38 Log CFU/g. E. coli, E. coli O157:H7, Salmonella spp. and L. monocytogenes were not isolated from any of the samples. The microbial contamination levels of strawberries determined in this study may be used as the fundamental data for microbiological risk assessment.

Profiles of Toxin Genes and Antibiotic Susceptibility of Bacillus cereus Isolated from Perilla Leaf and Cultivation Areas (들깻잎과 생산환경에서 분리한 Bacillus cereus의 독소 유전자와 항생제 감수성 분석)

  • Kim, Se-Ri;Lee, Ji-Young;Lee, Seo-Hyun;Ryu, Kyoung-Yul;Park, Kyeong-Hun;Kim, Byung-Seok;Yoon, Yo-Han;Shim, Won-Bo;Kim, Kyoung-Yul;Ha, Sang-Do;Yun, Jong-Chul;Chung, Duck-Hwa
    • Korean Journal of Food Science and Technology
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    • v.43 no.2
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    • pp.134-141
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    • 2011
  • Two-hundred Bacillus cereus isolated from perilla leaf cultivation areas in Miryang, Korea were investigated for toxin genes and antibiotic susceptibility. Toxigenic patterns of isolates were identified to be 11 groups through toxin gene profiles. 21% of strains isolated from the perilla leaves had both enterotoxin and emetic toxin. Toxin genes entFM (100%), nheA (100%) and hblA, C, D (65.5%) were frequently found in the perilla leaves, whereas EM (21.0%) was less common. Most isolates were susceptible to 10 antibiotics, but they were highly resistant to penicillin (100%), ampicillin (100%), oxacillin (94.9%), amoxicillin-clavulanic acid (95.6%), cefazolin (78.2%), and rifampicin (58.0%). These results indicate that food-borne outbreak caused by B. cereus might lead to diarrhea and emetic syndromes.

Investigation of Microbial Contamination Level during Production of Baby Leafy Vegetables (어린잎채소 생산 농장의 위생지표세균과 병원성미생물 오염도 조사)

  • Lee, Eun-Sun;Kwak, Min-Gyu;Kim, Won-Il;An, Hyun Mi;Lee, Hyo-Sup;Ryu, Song-Hee;Kim, Hwang-Yong;Ryu, Jae-Gee;Kim, Se-Ri
    • Journal of Food Hygiene and Safety
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    • v.31 no.4
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    • pp.264-271
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    • 2016
  • The purpose of this study was to investigate contamination sources of baby leafy vegetables by assessing microbial loads on baby leafy vegetables and agricultural inputs contacted with the vegetables. To estimate microbial loads, fecal indicators (coliform and Escherichia coli) and foodborne pathogens (E. coli O157:H7, Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus) were examined. A total of 126 samples including eleven kinds of leafy vegetables, irrigation water, media, and tools were tested, resulting in coliform contamination observed from most of samples. For E. coli, 10.3% (13/126) of the samples were positive including irrigation water, knife, handler, media, tools, and three kinds of leafy vegetables. B. cereus was detected from 38% (48/126) of the samples including media, tools and three kinds of leafy vegetables. No E. coli O157:H7, Salmonella spp., and L. monocytogenes was detected. This result implies that contacting with agricultural inputs could explain microbial load of baby leafy vegetables.

Change of fungi and mycotoxin in hulled barley under different conditions and period (저장 중 겉보리에 발생하는 곰팡이와 곰팡이독소 변화)

  • Ham, Hyeonheui;Baek, Jiseon;Lee, Mijeong;Lee, Theresa;Hong, Sung-Kee;Lee, Seungdon
    • Korean Journal of Food Preservation
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    • v.24 no.6
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    • pp.857-864
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    • 2017
  • To establish good storage practices for hulled barley against mycotoxin contamination, we measured occurrence of fungi and mycotoxin in hulled barley grains under various storage conditions. Hulled barley grains collected from two places were stored in five different warehouses: 1) two without temperature control, 2) one with temperature controlled at $12^{\circ}C$, 3) a chamber set at $15^{\circ}C/65%$ relative humidity, and 4) one seed storage set at $10^{\circ}C$. The samples were stored for six month with temperature and relative humidity monitored regularly. Every stored samples were retrieved after 0, 1, 3, and 6 month to investigate fungal and mycotoxin contamination. From the stored grains, Fusarium, Epicoccum, Alternaria, and Drechslera spp. were frequently detected. In the warehouses without temperature control, Fusarium and Alternaria spp. constantly decreased, whereas Drechslera spp. increased along with storage period. In the other warehouses with temperature controlled, Fusarium spp. decreased slowly and more than 2.5 log CFU/g of Fusarium spp. were detected after 6 month storage. The level of nivalenol was maintained during 0-3 month but increased after 6 month storage. There was no difference in the nivalenol levels between the warehouses. Therefore reducing storage period less than 6 months could be more effective to control nivalenol contamination in hulled barley grains.

Occurrence of Toxigenic Fusarium spp. and Zearalenone in Scabby Rice Grains and Healthy Ones (붉은곰팡이 감염 벼와 건전 벼의 독성 곰팡이와 제랄레논 발생)

  • Jang, Ja Yeong;Kim, Sosoo;Jin, Hyun Suk;Baek, Seul Gi;O, Sujin;Kim, Kyutae;Kim, Jeomsoon;Lee, Theresa
    • Research in Plant Disease
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    • v.24 no.4
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    • pp.308-312
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    • 2018
  • We analyzed rice sample with scab (collected in 2017) for fungal occurrence and found that frequency of Fusarium spp. was the highest among fungal genera. Within Fusarium, Fusarium asiaticum-nivalenol type dominated as 79%. Among mycotoxins, zearalenone was the highest toxin detected (1117 ng/g), followed by deoxynivalenol (163 ng/g), 15-acetyl deoxynivalenol (155 ng/g), nivalenol (110 ng/g). Analysis of mycotoxin levels in scabby and healthy grains (collected in 2015) revealed that both grain samples were contaminated with zearalenone. However, level difference of zearalenone between the samples was over 5 times as the scabby samples were 1400-2370 ng/g, while healthy ones were 240-430 ng/g. This result indicates that scabby grains should be removed when harvest to reduce zearalenone contamination in rice.

Effects of LED Treatment on Microbial Reduction and Quality Characteristics of Red Pepper Powder (LED 처리에 의한 고춧가루의 미생물 저감화 및 품질특성)

  • Yun, Hyejeong;Park, Kyeonghun;Ryu, Kyoung-Yul;Kim, Se-Ri;Yun, Jong-Chul;Kim, Byung Seok
    • Journal of Food Hygiene and Safety
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    • v.27 no.4
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    • pp.442-448
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    • 2012
  • This study investigated reduction of microbial population, water soluble pigment, capsanthin content, surface color (Hunter L, a, b, ${\Delta}E$), and sensory properties of pepper powder by LED (red, yellow, blue, green) treatments. LED (red, yellow, blue, green) treatment were conducted in 1,000 lux storage at $25^{\circ}C$ for 10 days. The total aerobic bacteria was no significant difference among the control and treated with LED during 10 days. In yellow LED treatment, yeast and molds were decreased about 1.76 log. Surface color such as lightness (L), redness (a), yellowness (b) were showed a decreasing tendency as the storage period. In the overall color difference (${\Delta}E$) of yellow LED treatment was lower less than 3.0. Water soluble pigment was no difference in control and LED treated samples during storage period. Capsanthin content was significantly decreased as storage period was increased, but no significant differences were observed among red and yellow LED treatments. Sensory properties of control was significantly reduced by storage period but yellow and green LED treatments were no significantly differences.

Rapid Detection Method for Fusaric Acid-producing Species of Fusarium by PCR (후자린산(Fusaric acid) 생성 Fusarium 종의 신속 검출 PCR)

  • Lee, Theresa;Kim, Sosoo;Busman, Mark;Proctor, Robert H.;Ham, Hyeonhui;Lee, Soohyung;Hong, Sung Kee;Ryu, Jae-Gee
    • Research in Plant Disease
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    • v.21 no.4
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    • pp.326-329
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    • 2015
  • Fusaric acid is a mycotoxin produced by species of the fungus Fusarium and can act synergistically with other Fusarium toxins. In order to develop a specific detection method for fusaric acid-producing fungus, PCR primers were designed to amplify FUB10, a transcription factor gene in fusaric acid biosynthetic gene cluster. When PCR with Fub10-f and Fub10-r was performed, a single band (~550 bp) was amplified from F. oxysporum, F. proliferatum, F. verticillioides, F. anthophilum, F. bulbicola, F. circinatum, F. fujikuroi, F. redolens, F. sacchari, F. subglutinans, and F. thapsinum, all of which were known for fusaric acid production. Whereas the FUB10 specific band was not amplified from Fusarium species known to be trichothecene producer. Because production of fusaric acid can co-occur in species that also produce fumonisin mycotoxins, we developed a multiplex PCR assay using the FUB10 primers as well as primers for the fumonisin biosynthetic gene FUM1. The assay yielded amplicons from fumonisin producers such as F. proliferatum and F. verticillioides, allowing for the simultaneous detection of species with the genetic potential to produce both types of mycotoxins.