• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.287-292
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• 2013

The efficient elution of viruses from contaminated food is a critical step for its detection. In this study, conditions optimal for enteric viral recovery from three leafy vegetables (cabbage, lettuce, sesame leaf) and three root vegetables (carrot, onion, mooli) were analyzed to find common buffers (statistically not different) applicable to the leafy and root vegetables. Viral recovery varied depending on the food matrices or elution buffers. Buffer solutions containing 0.25M threonine / 0.3M NaCl (pH 9.5) or 0.25M glycine / 0.14M NaCl (pH 9.5) could efficiently recover poliovirus from five out of six vegetables. The threonine buffer was applied to one leafy vegetable (sesame) and one root vegetable (carrot) for genogroup II norovirus (NoV) detection. The detection sensitivity was significantly higher from the leafy vegetable compared to the root vegetable. The use of these common elution buffers should facilitate the detection of low levels of NoV and other enteric viruses in a wide range of vegetables.

• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.40-45
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• 2018

Potassium in vegetables is known to have an adverse impact on a patient with chronic kidney desease. However, since vegetables also contain many other nutrient, consumption of vegetables by these patients is inevitable. The objective of this study was conducted to develop a fresh lettuce which contains low level of potassium for nephropathy in a closed-type plant factory system. Lettuce of "Charles" was used for experiment. The plants were cultivated in hydroponic system with a 16-h photoperiod at $15-21^{\circ}C$, 65% RH, $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$(LED W:R, 9:1) and $600-650mg{\cdot}L^{-1}$ $CO_2$ during 28 days. Nutrient solution which contains 1%, 5% and 10% potassium compared to conventional composition were supplied at 1 week and 2 weeks before harvest. The content of potassium and macro elements in leafy vegetables were analyzed by ICP emission spectroscopy after harvest. The potassium content in leaf of the 2 weeks before harvest treatment was significantly lower at than control. There were no significant differences between control and treatments in fresh weight and number of leaves. But there were differences among treatments. Considering the vegetable amounts consumed by nephropathy patients, the supply of nutrient which contain 1% and 5% potassium at 2 weeks before harvest was suitable for low potassium lettuce production. This study indicated that low potassium lettuce could be produced by developed nutrient composition and supply method.

• Horticultural Science & Technology
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• v.19 no.2
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• pp.140-144
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• 2001

Field investigations were initiated to determine possible new 'ssam' vegetable that could be grown during the summer season in highland. Korean 'ssam' means cooked rice in vegetables. The 'ssam' vegetable is called that those leaves has been used for wrapping at meal. Seventeen leafy vegetables were studied, including chard (Beta vulgaris L. var. flavescens DC.), leaf broccoli (Brassica oleracea L. var. italica), Chinese leek (Allium tuberosum Rottl.), Japanese hornwort (Cryptotaenia japonica Hassk), red leaf mustard (Brassica juncea L.), green leaf mustard (Brassica juncea L.), leaf parsley (Petroselinum crispum Nijim), pakchoi (Brassica campestris L. ssp. chinensis Jusl.) tatsoi (Brassica campestris var. narisoma), kale (Brassica oleracea var. acephala), collard (Brassica oleracea var. acephala), Korean mint (Agastache rugosa O. Kuntze), romaine lettuce (Lactuca sativa L. var. longifolia Lam.), red leaf chicory (Cichorium intybus L. var. folisum), red chicory (Cichorium intybus L. var. folisum), green leaf chicory (Cichorium intybus L. var. folisum), and sprouting broccoli (Brassica oleracea L. var. italica). Date of the first harvest in 1999 was July 10th in chard, leaf broccoli, red mustard, mustard, leaf parsley, pakchoi, tatsoi, kale, collard, Korean mint, red leaf chicory, red chicory, green leaf chicory, and sprouting broccoli. Date of the first harvest for Chinese leek, Japanese hornwort, and romaine lettuce was from the middle of June to the late of August. Based on ratings on marketable yield, we found good leaf shape, taste and yield in chard, red leaf mustard, green leaf mustard, pakchoi, tatsoi, romaine lettuce, red leaf chicory, red chicory, and green leaf chicory. Even though the most of all these vegetables were obtained high scores by test panels in shape, taste and quality, but some of them revealed inadequate leaf size as a 'ssam' vegetable. That problem will be solved by control of harvesting time. On the basis of this observation, chard, red leaf mustard, green leaf mustard, pakchoi, tatsoi, romaine lettuce, red leaf chicory, red chicory, and green leaf chicory were rated as promising 'ssam' vegetable by analysis of profits, adaptation, and quality.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.408-417
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• 2023

This study aimed to investigate the effects of an aquaponics system utilizing catfish recirculating water on the growth and water quality in lettuce and chicory cultivation. After 60 d of catfish cultivation in the BFT-AP, the survival rate was 96.0% and average weight gain was 178.5 g. The WGR grew by 241.4% and the SGR was 3.0%. A comparison between lettuce and chicory cultivation using BFT-AP and hydroponics revealed significant increases in shoot height, leaf count per week, and biomass of the cultivated lettuce and chicory. The SPAD values also increased significantly by 15.4-43.3%. Water quality analysis of the BFT-AP systems and crop cultivation beds showed significant differences, except for K and Na. The average NO₃^- concentration in the sediment pond was significantly higher at 45.3±1.0. Comparison of water temperature, pH, EC, DO, and ORP in the BFT-AP system and crop cultivation beds revealed similar monthly water temperatures from July to September. The pH in the catfish culture pond was 0.3-1.2 lower than that in the crop cultivation beds, and the EC was approximately 0.01- 0.03 dS/m lower in the catfish culture pond than the crop cultivation beds. The monthly average ORP in the catfish culture bed steadily increased to 479.9 mV in October. Bacillus velezensis (AFB2-2) and Chlorella fusca (CF) were applied to the biological activation bed; the population density of CF showed a continuous increase, whereas that of AFB2-2 decreased after 15 d and gradually increased thereafter. Thus, the application of the recirculating aquaponics cultivation technology with catfish (BFT) enhances catfish cultivation and promotes the growth of lettuce and chicory. Therefore, it is considered suitable for the environment-friendly cultivation of lettuce and chicory.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.314-321
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• 2007

This study was conducted to select leaf vegetables suitable for cultivation in apartment verandas and simple and easy fertigation method for home gardening. In order to develop the convenient fertigation method, hydroponics, wick irrigation, and overhead irrigation methods were compared. For the wick irrigation, two types of nutrient sources were used; one was slow release fertilizers mixed with medium and the other one was nutrient solution filled in container located under pots. The growth of leafy lettuce, leaf mustard, and leaf beet was better in both of the wick irrigation methods rather than in overhead irrigation and hydroponics. The wick irrigation method is very easy, so that it is expected to bring a good result from the cultivating and managing point of view, if it brings with commercialized system along with slow release fertilizer. As a result of investigation of environment such as temperature, relative humidity, and irradiance level in apartment verandas in autumn the highest irradiance level during a day was just 48% and 35% in verandas facing south and feeing southeast, respectively, comparing to that in greenhouse. The light environment was investigated as a limiting factor for vegetable growing in verandas. Therefore, to select the vegetables showing good growth under low irradiance environment, nine leaf vegetables such as romaine lettuce, lent lettuce, head lettuce, endive, pak-choi, leaf mustard, garland chrysanthemum, leaf beet, and Chinese chive were grown under 0%, 50%, 70%, 90% shading. Among them, Chinese chive showed the best growth under low irradiance levels. Endive showed line growth reduction according to shading degree, however, even under 90% shading condition, it showed good growth. And then leafy lettuce, garland chrysanthemum, and pak-choi followed. Therefore, these results will be of help in selecting vegetables for veranda gardening with different light levels.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.305-311
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• 2012

To investigate the influence electrical conductivity (EC) of nutrient solution and light intensity on growth of red leafy lettuce, fresh and dry weights, number of leave, chlorophyll concentration and production efficiency were evaluated through nutrient film technique system. The levels of EC were 0.5, 1.0, 1.5, 2.0, 3.0, and $6.0dS{\cdot}m^{-1}$, and those of light intensity were 120, 150, and $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Under photoperiod of 16 h/day, the temperature was maintained in the range of $20{\sim}25^{\circ}C$. Planting density was $10{\times}10cm$ (100 plants/$m^2$). When red leafy lettuce were grown in the EC range of $0.5{\sim}1.5dS{\cdot}m^{-1}$, the fresh and dry weights decreased as the EC levels and light intensity were lowered, however, Hunter's a value showed no significant differences among the treatments of EC and light intensity levels (Ex. 1). The fresh and dry weights and production efficiency ($g{\cdot}FW/kw$) were the highest in the treatment of $3.0dS{\cdot}m^{-1}$ and $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ when crops were grown under the EC range of EC $1.5{\sim}6.0dS{\cdot}m^{-1}$ (Ex. 2). But the fresh and dry weights, number of leaves, and production efficiency of $2.0dS{\cdot}m^{-1}$ were the highest when the light intensity was $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ (Ex. 3). The SPAD value increased gradually as EC levels were elevated. From the above results, we concluded that optimum levels of EC and light intensity were $2.0dS{\cdot}m^{-1}$ and $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, respectively, for production as well as production efficiency of red leaf lettuce in plant factory.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.293-301
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• 2013

This study was carried out to investigate the pesticide residue pattern among different leafy vegetables applied with foliar spraying under greenhouse and to check extrapolating from some residue trial data to other minor crops. Leafy vegetables used in this study were: Mustard greens (Brassica juncea L.), Kale (Brassica oleracea L.), Dacheongchae (a kind of pak-choi (Brassica rapa subsp. chinensis L.)), Leaf broccoli (Brassica oleracea var alboglabra), Perilla leaf (Perilla frutescens (L.) Britton var. Frutescens), Leaf lettuce (Lactuca sativa L.), Swiss chard (Beta vulgaris L. subsp. vulgaris) and Red leaf chicory (Cichorium intybus L. var. foliosum Hegi). These are cultivated all year under indoor or outdoor and cut the leaf from plant continuously during harvest time. The amounts of pesticide deposit in/on the continuous harvesting leafy vegetables were affected by the ratios of leaf area to weight. Ratio of perilla leaf was the largest among crops as 58 $cm^2/g$. The residue levels of 7 pesticides in/on perilla leaf were the highest than those of other crops through the statistical analysis from zero day to fifth day after last application. The representative crop in 8 crops was perilla leaf selected based on the amounts of daily consumption and the high residues. This study suggest that the continuous harvesting leafy greens should be separated from the one time harvesting leafy vegetables for the pesticide recommendations because of different harvesting habits and pre-harvest intervals.

• Journal of Food Hygiene and Safety
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• v.35 no.4
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• pp.319-325
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• 2020

Widespread consumption of fresh-cut vegetables without cooking results in ingestion of major foodborne pathogens including Bacillus cereus. In this study, we aimed to develop a method to rapidly detect B. cereus in fresh-cut vegetables by combining commercial PCR analysis with enrichment of the pathogenic levels. A mixture of B. cereus strains (KCTC1013, KCTC1014, KCTC1092, KCTC1094, and KCTC3624) was inoculated on the surface of fresh-cut cabbage lettuce (20 g) and baby leafy vegetables (10 g) to concentration 1, 2, 3, 4, and 5 log CFU/g. Eighty milliliters of TSB with 0.15% polymyxin B was used for cabbage lettuce, and 90 mL of medium was used for baby leafy vegetables and incubated at 42℃ for 0, 2, 3, 4, 5, 6, and 7 h. One milliliter of the enriched media was plated on mannitol-egg yolk-polymyxin agar for quantification, and another 1 mL was used for DNA extraction for PCR analysis. Additionally, the minimum number of sub-samples to be tested from a pack of fresh-cut vegetable samples was determined using 5 sub-samples. The results from this study showed that for detecting B. cereus in fresh-cut cabbage lettuce, 3, 4, 5, 6, and 7 h enrichment were required to at least detect 5, 4, 3, 2, and 1 log CFU/g of B. cereus, respectively. B. cereus in fresh-cut baby leafy vegetables could be detected after 2, 3, 4, 5, and 6 h of enrichment at 5, 4, 3, 2, and 1 log CFU/g, respectively, using a combination of enrichment and PCR analysis. To determine if a pack of fresh-cut vegetable is positive, the minimum number of sub-samples should be 3. These results can be used to develop a rapid detection method to semi-quantify B. cereus in fresh-cut vegetable samples combining enrichment and PCR.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.364-375
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• 2014

This study was carried out to investigate the pesticide efficacy and crop safety among different leafy vegetables applied with foliar spraying under greenhouse and to check extrapolating from some trial data to other minor crops. Leafy vegetables used in this study were: lettuce (Lactuca sativar), leaf broccoli (Brassica oleracea.), chicory (Cichorium intybus.), chinese cabbage (Brassica campestris subsp. napus var. pekinensis), radish (Raphanus sativus), rape (Brassica napus), crown daisy (Chrysanthemum coronarium), edible burdock (Arctium lappa), endive (Cichorium endivia) and mustard greens (Brassica jumcea). Based on the result of control efficacy, all crops were classified into the groups. The results showed the probabilities of extrapolating the control value data of minor crop within the same group. It would be possible to use the pesticides which are already been registered for similar crops to those crops have no registered pesticides.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.237-243
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• 2013

Pesticides were sprayed on perilla leaf and leafy lettuce in a greenhouse and the reduction rate of pesticide residues on each vegetable by washing were tested. The reduction rate of pesticide residues by washing for 30 sec~3 min on perilla leaf were 3~63% in tap water, 2~58% in salt water, 6~74% in green tea water, and 8~86% in detergent solution. The detergent solution only showed significant difference in reduction rates compared to the tab water washing. Considering reduction effects of the washing duration, it was showed that the reduction rates were a pattern of inclining as the duration of washing process increased, but there was no significant difference in the reduction rates except the reduction rates between washing in the detergent solution for 1 min and 3 min. Comparing washing in flowing tab water and in stagnant tab water with leafy lettuce, the reduction rate by one time washing were 8~68% in flowing tab water and 7~64% in stagnant tab water. The water and the time used in this experiment were 17.5 L, 2.9 min with flowing tab water and 4 L, 1 min with stagnant tab water. The reduction rate by 3 times washing in stagnant tab water were 16.5~76.6%, and the water and the time used were 12 L, 3 min. Therefore, when the water and the time used to wash vegetables were considered, washing two or three times in stagnant tab water could be more effective than washing one time in flowing tab water.