• Food Science and Preservation
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• v.24 no.1
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• pp.27-35
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• 2017

Microbiological, physicochemical, and organoleptic properties of fresh-cut vegetables (FVs), carrots, green peppers, cherry tomatoes, and paprika after X-ray irradiation were evaluated to verify food quality suitable for the immune-depressed patients. Total concentrations of aerobic bacteria in non-irradiated samples, except for cherry tomatoes, were 1.63-3.34 log CFU/g. Irradiation dose exceed 0.4 kGy was used for carrots and green peppers whereas the sterilization dose of 0.2 kGy was used for both cherry tomatoes and paprika. A dose of 0.4 kGy was tentatively determined as the minimum allowable dose for sterilization of the FVs, based on $D_{10}$-values of X-ray irradiation (0.11-0.32 kGy) for Escherichia coli, Listeria monocytogenes, and Salmonella Typhimurium inoculated on the samples. With respect to the physiological properties, only hardness was significantly decreased as the absorbed dose increased; however, there were no significant differences in hardness of the sterilized samples using X-rays at 0.4 kGy compared with those of non-irradiated samples (p<0.05). Moreover, overall acceptance scores of the sterilized FVs were higher than 5.0 points on a 7-point scale, indicating a good organoleptic quality. In a survey on preference of hospitalized patients with cancer (n=50), the average scores for the sterilized FVs, except for carrots, were higher than 4.0 points. In conclusion, it is considered that the FVs, except for carrots, sterilized using X-rays at 0.4 kGy could be served to immune-depressed patients as hygienically safe foods with acceptable organoleptic properties.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1119-1124
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• 1997

This study was carried out for improvement and correction of the traditional pressure variation method (PVM) in the respiration rate measurements of fresh fruits and vegetables using a microcomputer system and a differential pressure sensor. Water vapor pressure in the container was calculated by equations for psychrometric calculations. At the beginning of experimental period water vapor pressure in the container was increased and maintained constantly in the most experimental period, but was decreased dramatically after $CO_2$ scrubbing. The percentages of water vapor pressure on total differential pressure were $33{\sim}46%$ at $1^{\circ}C$, $23{\sim}45%$ at $11^{circ}C$ and $35{\sim}53%$ at $21^{\circ}C$. The differences between the respiration rates determined by gas chromatography and corrected pressure variation method (CPVM) were $0.2{\sim}0.3\;mgCO_2kg^{-1}h^{-1}$ at $1^{\circ}C$, $0.2{\sim}2.9\;mgCO_2kg^{-1}h^{-1}$ at $11^{\circ}C$ and 1.0{\sim}9.0\;mgCO_2kg^{-1}h^{-1}$ at $21^{circ}C$, while those between gas chromatography and normal pressure variation method (PVM) were $0.8{\sim}1.2\;mgCO_2kg^{-1}h^{-1}$ at $1^{\circ}C$, $3.9{\sim}11.0\;mgCO_2kg^{-1}h^{-1}$ at $11^{\circ}C$ and $8.0{\sim}32.0\;mgCO_2kg^{-1}h^{-1}$ at $21^{circ}C$, respectively. The differences of the respiration rates with CPVM were smaller than those with PVM. CPVM, therefore, were more exact and convenient method than PVM in the measurement of respiration rate of fresh produce.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.303-308
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• 2015

The consumption of leaf vegetables has been steadily increasing in Korea. Leaf vegetables are used for "Ssam (vegetable wrap-up), eaf vegetables has been steadily increasing in Korea. Leaf vegetables are used for asoned condiments inside several layers of young vegetable leaves. This study investigated the effect of air temperature on the growth and phytochemical contents of beet (Beta vulgaris L.) and Ssamchoo (Brassica lee L. ssp. namai) grown in a closed-type plant factory system where fluorescent lamps were used as an artificial light source. Seeds of beet and Ssamchoo were sown in a peat-lite germination mix. The roots of 20-day-old seedlings were washed, and the seedlings were planted on a styrofoam board and grown in hydroponic beds for 25 days under fluorescent light. Plants were exposed to one of three different air temperature regimes (20, 25 and $30^{\circ}C$ during the day combined with $18^{\circ}C$ during the night), which were monitored with a sensor at 30 cm above the plant canopy. Increased plant height and leaf area were observed in beet at $25^{\circ}C$ and $30^{\circ}C$ compared to $20^{\circ}C$. For Ssamchoo, the greatest plant height, leaf area, fresh weight and dry weight were obtained at $20^{\circ}C$. Ascorbic acid content of beet and Ssamchoo leaves were highest at $30^{\circ}C$. In beet, total polyphenol and flavonoid contents were higher at $20^{\circ}C$ (42.4, $197.0mg{\cdot}g^{-1}DW$) and $25^{\circ}C$ (46.9, $217.0mg{\cdot}g^{-1}DW$) than $30^{\circ}C$ (22.4, $88.0mg{\cdot}g^{-1}DW$). In Ssamchoo, total polyphenol and flavonoid contents were also higher at $20^{\circ}C$ (79.2, $268.2mg{\cdot}g^{-1}DW$) and $25^{\circ}C$ (66.3, $258.3mg{\cdot}g^{-1}DW$), respectively, than $30^{\circ}C$ (53.7, $134.7mg{\cdot}g^{-1}DW$). Hence, the optimum temperature appears to be $20^{\circ}C$ for growing both beet and Ssamchoo in a closed-type plant factory system with fluorescent light.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.872-878
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• 2014

This study aimed to enhance storage and freshness of strawberry fruits and foliage vegetables by spray treatment with Chlorella vulgaris as a bio-fertilizer. The tested strain, C. vulgaris CHK0008, was isolated from an organically cultivated rice paddy and identified as C. vulgaris by its morphology and 18S rDNA and 23S rDNA sequence homology. We successfully cultured C. vulgaris CHK0008 in BG11 modified medium (BG11MM) and adjusted $2.15{\times}10^6cell/mL$ C. vulgaris CHK0008 to one OD value by measuring the optical density at 680 nm using a UV-vis spectrophotometer. The soluble solid content of 'Seolhyang' and 'Yukbo' strawberry fruits treated by spray application with C. vulgaris CHK0008 was enhanced by 22.2% and 11.5% respectively, compared to untreated controls. Additionally, the decay rates of treated 'Seolhyang' and 'Yukbo' strawberry fruits decreased 63.8% and 74.4% respectively, compared to untreated control. Surface color changes and chlorosis of leaves in leaf vegetables such as lettuce, kale, red ornamental kale, white ornamental kale and beet were observed in samples treated with water spray for 10 days after cold storage. However, the decay rate of leafy vegetables treated with foliar application of 25% C. vulgaris CHK0008 liquid culture was significantly decreased compared to that of the untreated control during storage at $4^{\circ}C$.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.400-407
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• 2014

Urban farming supplies emotional stability and fresh vegetables to participating persons, however, no information regarding the biosafety of agricultural products from urban farming is available. Here, we collected 260 samples of Chinese cabbages and lettuce from 4 urban community gardens and 6 roof gardens in Seoul from September through October 2012, and monitored the microbiological and parasitological contamination quantitatively and/or qualitatively. The mean counts of total aerobic bacteria and coliforms were $6.1{\pm}0.8\;log\;CFU{\cdot}g^{-1}$ ( range, $5.4{\pm}0.6{\sim}7.1{\pm}0.8\;log\;CFU{\cdot}g^{-1}$) and $4.0{\pm}0.7\;log\;CFU{\cdot}g^{-1}$ (range, $2.3{\pm}0.6{\sim}6.1{\pm}0.9\;log\;CFU{\cdot}g^{-1}$), respectively. Coliforms were detected on 59.6% among 260 vegetable samples. There were no significant differences in the contamination levels of total aerobic bacteria and coliforms between the Chinese cabbages and lettuce, whereas both levels of vegetables from urban community gardens were higher than those of roof gardens (p > 0.05). Escherichia coli was isolated at 3.1% among whole vegetables, and contamination level was $1.5{\pm}0.2\;log\;CFU{\cdot}g^{-1}$. Among foodborne pathogens, Staphylococcus aureus was detected in 1.5%, however, Salmonella spp., Listeria monocytogenes and E. coli O157:H7 were not detected on any of the vegetable samples. We also found undefined parasite eggs from two samples of Chinese cabbages (0.8% of total vegetables we tested). From these study, we found the presence of microbial contamination of agricultural products from urban farming, thus we need further concern to improve the biosafety during production of agricultural products.

• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.465-474
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• 2011

Agricultural environment of Lam Dong province, which is located in central highland area, is totally different from that of other lower areas in Vietnam. In Lam Dong province, abundant plant resources were naturally grown such as pine trees, taxus, and wild orchids, which can grow in high mountainous area. In Lam Dong, the field proportion of perennial crops was higher than that of annual crops. However, the field proportion and yields of vegetables were highest among the all cultivated crops, estimating 38% (36,552ha) and 72% (993,082MT), respectively. Especially in Da Lat, vegetables, flowers, orchids, and industrial crops were mainly produced because this area is geographically close to Ho Chi Minh city. And also in Da Lat, 64% (8,447ha) and 36% (4,777ha) of farm fields were used for producing annual and perennial crops, respectively, and the yields of fresh vegetables in this area was estimated to 213,478MT which was 21.5% of the whole yields in Lam Dong province. Thus Korea, Taiwan, Japan, France, and Holland have invested to agriculture in Da Lat for producing and exporting flowers, vegetables, and tea. In 2009, flower cultivation area of Da Lat was over 55% in Lam Dong province and average amount of values were 9,781 million USD, which was higher than that of al other crops. Thus following strategies could be suggested for the development of agriculture in Lam Dong province. The first, agricultural cooperation with Da Lat, Lam Dong, should be characterized to horticulture and floriculture, followed by supporting both appropriate R&D techniques and equipments. And then agricultural system should be made in relationship with the local companies. Finally, agricultural cooperation program should be conducted toward the direction for both donor and recipient countries.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.659-667
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• 2000

Quality attributes of fresh-cut green onion(Allium fistulosum L.) as affected by rinsing and packaging were investigated in terms of flesh weight, color, viable cell counts, sensory properties during storage at $10^{\circ}C$. Fresh green onions were trimmed, cut, and rinsed with cold water(approximately $5^{\circ}C$) as well as chlorine solution(100 mg/L) and then packaged in low density polyethylene film pouches of $63\;{\mu}m$ thickness. Rinsing treatments with cold water or chlorine solution did not significantly influence changes in microbial populations but sensory characteristics, resulting in cut green onions of better visual quality as compared to the control without rinsing. Fresh-cut green onions were also rinsed with cold water and packaged in sealed bags of low density polyethylene films with different thickness(22, 36, $63\;{\mu}m$), and stored at $10^{\circ}C$ for 18 days. Thickness of polyethylene film was a significant factor for microorganisms populations and sensory attributes. Mesophilic aerobic bacterial count after 13 days for the control, packed in punched film bags, was $3.07{\times}10^6}$ CFU/g, while those for samples in hermetically sealed bags ranged only $1.74{\sim}2.02{\times}10^5}$ CFU/g. Gas composition within the sealed packages changed from normal air to about $1.3{\sim}5.4%\;O_2$ and $4.0{\sim}8.0%\;CO_2$ after 13 days of storage. Particularly, the visual sensory quality of cut green onion samples was retained better in polyethylene film bags of $63\;{\mu}m$ thickness(gas transmission rate: 600 $O_2\;mL/day{\cdot}m^2{\cdot}atm;\;2,500\;CO_2\;mL/day{\cdot}m^2{\cdot}atm$) than in the others.

• Korean Journal of Food Science and Technology
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• v.45 no.5
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• pp.545-549
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• 2013

Liquid paraffin is a mixture of heavier alkanes derived from petroleum. It can be used as a lubricant in processing machinery, as a coating agent, or as a releasing agent. The purpose of this study was to analyze liquid paraffins in foods by using a gas chromatography-flame ionized detector (GC-FID). Liquid paraffin was extracted from the food samples using n-hexane. Non-polar aromatic or olefinic co-extractives were removed by alkaline permanganate oxidation followed by clean up on an aluminium oxide SPE cartridge before the GC-FID analysis. The results of recovery tests were 91.5-103.2%. Based on this optimized method, we investigated the amount of liquid paraffin in various food samples purchased from domestic markets. The levels of liquid paraffin in bread were $95.5{\pm}156.0$ mg/kg (0.008%), those in capsules were $40.2{\pm}54.5$ mg/kg (0.001%), and those in dried fruits and vegetables were $3.0{\pm}18.1$ mg/kg (0.0001%). No liquid paraffin was detected in fresh fruits and vegetables. We propose that our method can be used to monitor and detect liquid paraffin in foods for food safety management.

• Journal of Food Hygiene and Safety
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• v.20 no.3
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• pp.147-158
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• 2005

A food safety survey was conducted to assess the housewives' handling practices and consumption of potentially risky foods in family home. More than $40\%$ of the respondents wash their hands without soap or use their wash towels after contact with potentially risky foods such as meat, poultry, fish, shellfish, raw eggs, meat processed foods, raw fruits and vegetables. Over half of the respondents have consumed undercooked eggs without recognizing the potential health risk of consumption of raw eggs. $34\%$ of the respondents do not wash their hands after breaking raw eggs, indicating high risk of cross contamination while handling raw eggs. More than $60\%$ of the respondents just use running water to wash fresh fruits and vegetables. $78.9\%\;and\;45.2\%$ of the respondents have consumed sushi/sashimi or raw oysters, respectively in the past 12 months. The results of this study indicate the substantial risks of unsafe food-handling practice at the points of cross-contamination, cooling practices, storage time, and consumption of potentially risky foods at home. Considering the housewives' participation in school food service, development of food safety education program for the housewives is needed to promote safe handling practices of potentially risky foods.

• Korean journal of food and cookery science
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• v.26 no.1
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• pp.104-109
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• 2010

Korean Chinese cabbage (Brassica campestris L. ssp. pekinensis) is one of the major cruciferous vegetables. Cruciferous vegetables contain a series of relatively unique secondary metabolites of amino acids called glucosinolates. Although glucosinolates do not appear to be bioactive, they are hydrolyzed by plant myrosinase when the cells in plants are damaged, and release biologically active compounds such as isothiocyanates, nitriles, and thiocyanates. The objective of this study was to determine the myrosinase activity and total glucosinolate levels of Korean Chinese cabbages by different salting times (0, 12, 18, and 24 h) and salt concentrations (6, 10, 14%). The total water content, salt content, and pH of brined cabbages decreased with increasing salting time. The myrosinase activity as determined by a glucose kit, decreased with increasing salting time and salt content. The total glucosinolates were purified using an anion exchange column and measured by UV-visible spectrophotometer. The fresh Korean Chinese cabbages contained $25.38{\pm}1.45\;{\mu}mol/g$ dry weight of glucosinolates. However, the total glucosinolates of brined cabbages decreased with increasing salting time and salt concentration. After 24 h of salting time, the total glucosinolates of brined cabbages rapidly decreased by $16.12{\pm}11.09$, $11.25{\pm}10.91$, $9.29{\pm}10.73\;{\mu}mol/g$ in 6%, 10%, and 14% salt solution, respectively. Overall, the total glucosinolate levels of Korean Chinese cabbages were found to vary inversely with salting time and salt concentration.