• Food Science and Biotechnology
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• v.15 no.3
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• pp.341-346
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• 2006

This study was performed to examine the effects of ${\gamma}$-irradiation on the volatile flavor compounds of dried leeks (Alliums tuberosum R.). Volatile compounds of dried leeks were extracted using simultaneous steam distillation and extraction (SDE), and analyzed by gas chromatography/mass spectrometry (GC/MS). Forty-one, 51, 45, and 42 compounds were tentatively identified in control, 1, 3, and 10 kGy irradiated samples, respectively. The constituents of flavor compounds in irradiated dried leeks were similar to non-irradiated samples. However, the intensities of the peaks were clearly different between them. Sulfur-containing compounds were detected as dominant compounds in all samples and their amounts decreased after ${\gamma}$-irradiation. ${\gamma}$-Irradiation reduced the total concentration of volatile compounds from leeks by 23.19, 15.09, and 30.23% at 1, 3, and 10 kGy doses, respectively.

• Journal of Food Hygiene and Safety
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• v.30 no.3
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• pp.249-257
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• 2015

The purposes of this study were to develop a small scale post-harvest facility, and consequently to evaluate the effects of applying the facility along with hygiene education on the level of microbial safety in Korean leeks production. A total of 135 samples were collected at three Korean leeks farms in Yangju, Gyeonggi province. Food safety indicators (Aerobic plate count (APC), coliform count, and Escherichia coli) and foodborne pathogens (E. coli O157:H7, Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus) on/in the samples were assessed. The microbial load measured as APC with harvesting tools such as comb, chopping board, and knife, at the farms where the small scale post-harvest facility had been operated (Farms A and B) was lower than that at another farm having no post-harvest facility (Farm C) by 1.44~2.33 log CFU / $100cm^2$. Moreover, the chopping board from Farm C was observed being contaminated with B. cereus at 6.03 log CFU / $100cm^2$. The coliform counts from the samples increased by 0.57~1.89 log CFU/g after leeks was submerged in ground water for washing. E. coli was recovered from leeks, soil, and the ground water used in the washing process, while no E. coli O157:H7, Salmonella spp., and L. monocytogenes was detected. Our results indicated that the small scale post-harvest facility developed in this study as well as the hygiene education played an important role in enhancing the level of microbial food safety in the leeks production environment. However, a disinfection technique could be needed during the washing step in order to prevent a potential contamination.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.28-34
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• 2015

This study is to investigate microbiological hazards which can be used as fundamental data to adequately control leeks hazards and develop leeks GAP model for those who want to get GAP system. The microbiological investigations on cultivation environments (soil and water), crops (leeks), personal hygiene (workers' hands, clothes and gloves) and working tools (boxes) have been conducted for one year, so the period was classified under non-cultivation, cultivation, and post harvest. Total bacteria was detected from soil (4.0~6.7 log CFU/g), leeks (4.6~5.1 log CFU/g), hands (ND~3.3 log CFU/hand) and gloves ($ND{\sim}5.4\;log\;CFU/cm^2$) while nothing was detected from the other samples. The coliform contamination of leeks (4.8~5.0 log CFU/g) was more high than that of soil (3.9~4.2 log CFU/g). In case of foodborne pathogens, only B. cereus was detected at the level of 0.5~4.6 log CFU/g (or hand, $100cm^2$). Fungi was observed at the level of 2.1~3.8 log CFU/g (or hand, $100cm^2$) excepting water and some working tools. These results demonstrate that the contamination of leeks is comparatively higher than that of soil sample. The reason may be the cross-contamination by biological hazards presenting on soil. Therefore, it is necessary to properly control soil and fertilizer for safety against biological hazards.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.577-583
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• 2012

This study investigated the antioxidant activities, and antimicrobial activity $in$ $vitro$ of an 80% ethanol extract from garlic, daikon, leek, ginger, onion, and green onion, which are widely-used ingredients in Korean food that contain sulfur. The total polyphenol content in ginger and leek extracts showed a high value ($233.63{\pm}4.59$ and $220.98{\pm}10.56$ mg/g GAE) and onions, leeks, garlic, and daikon followed by with $69.07{\pm}1.42$, $68.83{\pm}2.11$, $19.41{\pm}0.40$, $19.05{\pm}03.32$ mg/g GAE, respectively. DPPH radical scavenging activity was highest with ginger extracts ($1.57{\pm}0.15$ mg/mL as $IC_{50}$) followed in order of decreasing activity by leeks, onions, daikon, green onions, and garlic. The results of ABTS radical scavenging activity and FRAP value showed higher antioxidant activity in extracts from ginger and leek. The order of vegetables with most to least prevalent ABTS radical scavenging activity was green onions, onions, garlic, and finally daikon. From greatest to least FRAP value, the relevant vegetables were green onions, onions, daikon, and garlic (p<0.05). Ginger extracts showed promise against seven strains of microbes: $Bacillus$ $cereus$, $Bacillus$ $subtillis$, $Staphylococcus$ $aureus$, $Lactobacillus$ $plantarum$, $Escherichia$ $coli$, $Salmonella$ $enterica$, and $Pseudomonas$ $aeruginosa$. Garlic extracts (5 mg/disc) showed strong antimicrobial activity against $B.$ $cereus$ (22.3 mm) and $E.$ $coli$ (24.3 mm). Extracts of both onion and green onion showed antimicrobial activity against only $E.$ $coli$ (12.7 and 10.3 mm) and $B.$ $cereus$ (12.0 and 12.5 mm) at 10 mg/disc, and the inhibition zone diameter from extracts of garlic and leeks were 18.0 mm and 10.4 mm vs. $L.$ $plantarum$ at 10 mg/disc. This study showed positive antioxidant activities for ginger and leeks, and positive antimicrobial activities for leeks and garlic. These sulfur-containing vegetables are widely used in Korean food. Leeks especially could serve as a functional food preservative.

• Journal of the Korean Society of Food Culture
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• v.20 no.2
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• pp.186-193
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• 2005

The antioxidative and antimicrobial activities were carried on the leeks (Allium tuberosun R.) ethanol extracts in order to find out new food functional components. Three species of leeks used in this study were Chinese leek(long type, LL), general leek(medium type, LM), and medicinal leek (short type, LS). Total amounts of polyphenol compounds in LS was shown as the highest (436.60mg%) value. All of ethanol extracts of these leeks were shown to be had good electron donating ability(EDA) and nitrite scavenging activity. Specialty, the ethanol extract of LS(LSEx) had the highest EDA 30.47% and nitrite scavenging activity 77.24% and the lowest was LMEx. The antioxidative activities of these ethanol extracts on the corn germ oil were measured by peroxide values(POV) and conjugated diene values (CDV) storaging for 30 days at $60{\pm}2^{\circ}C$. The antioxidative activities of these extracts by POV and CDV were determined as following order as LSEx> LLEx) LMEx. The antioxidative activities of all extract were presented as high tendency by increasing adding amounts (0.02%>0.05%>0.1%). When the antioxldative activities were compared with BHT and ${\alpha}-tocopherol$, the degree of the antioxidative activities of these extracts were certified as lower than BHT and higher than ${\alpha}-tocopherol$. And also LSEx, LMEx, and LLEx had antimicrobial effects on the several micro organisms, especially the effect on the Pseudomonas aeruginasa was remarkable. While LMEx had shown inhibit effect on most of micro organism used in this study.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.152-158
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• 2001

In this study, we determined major foods and food groups which contributed to the intake of folate in korean child-bearing women. Folate content of the major foods was also analyzed. A total of 91 healthy women with childbearing potential participated. They were divided into one of three groups by age; A (15∼24 yrs), B(25∼34 yrs) and C (35∼49 yrs). Food consumption data of the subjects were obtained by the 24-hr recall method. The rate of contribution of each food to the total intake of dietary folate was determined. Seventy major foods for folate were selected from the 178 foods they consumed. Two sets of the 70 foods were collected from different markets. After extracting folates from the foods by heating with a HEPES-CHES buffer, the samples were treated with α-amylase, protease and folate intakes was Korean cabbage kimchi followed by laver, soybean sprout, rice, yolmu kimchi, eggs, lettuce, perilla leaves, sea mustard and radish root. Food items that contributed to folate intake were slightly different among the age groups. Although the folate content of Korean cabbage kimchi was 51.6 ㎍/100g, but due to the high amount of intake, it was ranked the first major food prviding folate. High folate foods containing over 100㎍/100g were laver, corn flakes, spinach, mungbean, sesame, quail's eggs, small radish kimchi, kidney beans, leeks and peanuts. However, based on the serving size, spinach, corn flakes, leeks, sweet potato, pepper leaves, quail's eggs, crown daisy, small radish kimchi and perilla leaves contributed above 50㎍ of folate per serving size.

• Food Science of Animal Resources
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• v.32 no.1
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• pp.1-5
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• 2012

The objective of this study was to examine the effects of a combined treatment regarding antimicrobial food ingredients and high pressure processing (HP) on the inactivation efficiency of Escherichia coli and Listeria monocytogenes inoculated into ground pork. Ethanol extracted from garlic, leeks, onions, and ginger powder was prepared. Half of the prepared powder was irradiated at 5 kGy to see the effect of pasteurization before addition. The prepared food ingredients were added into radiation-sterilized ground pork (1%, w/w), and inoculated with E. coli and L. monocytogenes. The samples were vacuum-packed and applied with HP at 0.1 (control), 300, 450, and 600 MPa. Microbial log reduction increased with the increase of pressure up to 600 MPa. With minor exceptions, overall efficiency of HP treatment with regards to inactivation of pathogens increased. Inoculated microorganisms showed approximately 7-8 Log reductions by 600 MPa, except for L. monocytogenes treated with garlic (5.7 Log reductions). The E. coli reduction in ground pork mixed with ethanol extracted garlic showed the highest efficiency (1.86) compared to leeks (1.25-1.31), onions (1.17-1.44), and ginger (1.50-1.82) when treated at an HP of 450 MPa. There was no evidence for the advantage of pasteurization concerning the food ingredients before addition of antimicrobial food ingredients and HP. Results demonstrate that the combination of antimicrobial food ingredients and HP treatment may help improve the efficiency of sterilization in meat systems.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.534-541
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• 2019

his study assessed microbial contamination of leeks and leek-cultivated soil. Leeks and leek-cultivated soil were collected in A and B regions and accounted for 39 and 33 samples, respectively. All of the samples were analyzed for the presence of sanitary indicator bacteria (total aerobic bacteria, coliforms and Escherichia coli), Salmonella spp., E. coli O157:H7, Listeria monocytogenes, and Bacillus cereus. In A and B region, the total aerobic bacteria was in the range of 5.87-8.78 log CFU/g for leeks and 5.94-8.45 log CFU/g for leek-cultivated soil. The coliform in leeks and leek-cultivated soil was in the range of 1.20-7.36 log CFU/g and 2.45-5.87 log CFU/g, respectively. B. cereus was detected from some of the samples while other pathogens were not detected. This study provides important background information on the microbiological safety of fresh vegetable cultivation environments.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.4
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• pp.513-518
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• 2005

Volatile compounds of $\gamma-irradiation$ leeks (Aillum tuberosum R.) were isolated by simultaneous steam distillation and extraction method (SDE) and analyzed by gas chromatography/mass spectrometry (GC/MS) along with the non-irradiated sample. Leeks were irradiated at dose of 20 kGy and non-irradiated samples were considered as control sample. 56 and 54 compounds were identified in non-irradiated and irradiated samples, respectively. These components included the functional groups; alcohols, aldehydes, esters, ketones, N- and S-containing compounds. S-containing compounds such as dimethyl trisulfide, methyl-(Z)-l-proenyl trisulfide, dimethyl disulfide, 3-ethyl-l,2-dithi-5-ene and methyl allyl disulfide were the major compounds. Methyl-(Z)-l-propenyl trisulfide, diallyl trisulfide, (E)-2-hexanal and 3-ethyl-l,2-dithi-5-ene were clearly decreased by the $\gamma-irradiation$, but dimethyl disulfide, diallyl sulfide, allyl methyl sulfide and pyridine were increased by the $\gamma-irradiation$.

• Korean Journal of Food Science and Technology
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• v.42 no.6
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• pp.664-675
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• 2010

This survey was carried out to estimate pesticide residue levels in commercial agricultural products in the year 2009. Residues were examined in 16 commodities (rice, foxtail millet, buckwheat, kidney beans, peanuts, sesame, oranges, grapefruit, kiwifruit, spinach, perilla leaves, leeks, garlic stem, garlic, ginger, and oak mushroom) collected from 22 provinces in Korea. Analyses were performed by multi-methods capable of detecting up to 60 pesticides by LC/MS/MS. A total of 510 samples were collected and analyzed. Of the samples, 96.1% contained no detectable pesticide residues. Detectable residues at or below the MRLs were found in 3.5% of the samples. However, in 0.4% of the samples (spinach and leeks), residue (ethaboxam and fluquinconazole) levels exceeded the MRLs. Furthermore, intake assessments of 7 kinds of pesticide residues were carried out, excluding those exceeding the MRLs. The results showed that the ratios of EDI (estimated daily intake) to ADI (acceptable daily intake) were 0.0001-0.0006%, which indicates that the detected pesticide residues were in a safe range. It is concluded that residual pesticides in agricultural products are properly controlled in Korea.