• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.67-71
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• 2017

This study examined the antimicrobial activity of flaxseed meal extract (FME) against Staphylococcus aureus and Escherichia coli O157:H7 inoculated on red mustard. With the treatment of 0.7% FME for 3 min, the reduction levels of S. aureus and E. coli O157:H7 populations were 1.23 and 1.83 log CFU/g, respectively. In addition, the combined treatment of 0.7% FME at $50^{\circ}C$ for 3 min reduced the populations of the pathogenic bacteria by 2.28 and 2.41 log CFU/g, respectively. The color and the vitamin C content were not significantly different between treatments. Thus, FME can be used as a novel antimicrobial agent in fresh-cut vegetables.

• Food Science of Animal Resources
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• v.34 no.5
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• pp.665-673
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• 2014

We compared standard culture methods as well as conventional PCR and real-time PCR for the detection of Listeria monocytogenes (L. monocytogenes) in milk, cheese, fresh-cut vegetables, and raw beef that have different levels of background microflora. No statistical differences were observed in sensitivity between the two selective media in all foods. In total, real-time PCR assay exhibited statistically excellent detection sensitivity (p<0.05) and was less time consuming and laborious as compared with standard culture methods. Conventional culture methods showed poor performance in detecting L. monocytogenes in food with high levels of background microflora, generating numerous false negative results. While the detection of L. monocytogenes in fresh cut vegetable by culture methods was hindered only by L. innocua, various background microflora, such as L. innocua, L. welshimeri, L. grayi, and Enterococcus faecalis appeared on the two selective media as presumptive positive colonies in raw beef indicating the necessity of improvement of current selective media. It appears that real-time PCR is an effective and sensitive presumptive screening tool for L. monocytogenes in various types of foods, especially foods samples with high levels of background microflora, thus complementing standard culture methodologies.

• Journal of the Korean Dietetic Association
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• v.26 no.2
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• pp.116-125
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• 2020

The purpose of this study was to assess the sugars contents of home meal replacement (HMR) products currently sold in Korea. This study surveyed and examined the sugars contents in 835 popular HMRs (294 ready-to-eat foods; RTE, 499 ready-to-cook foods; RTC, 42 fresh-cut vegetables; FCV) through the nutrition labels. The average price, weight and energy content of 835 HMR products were 3,917.5 Korean won, 336.0 g, and 522.7 kcal, respectively. The sugars content per product was significantly higher in the RTCs (13.4 g) and RTEs (10.3 g) than that in the FCVs (4.2 g) (P<0.001), and the percentage of energy from sugars was 9.7% for the RTEs, 10.2% for the RTCs, and 8.7% for the FCVs without any significant difference. The sugars contents of 9 RTE types were in the order of side dishes (34.3 g), sunsik (22.5 g) and hamburgers (12.1 g) per package. The percentage of energy from sugars was highest in side dishes (28.1%), followed by kimchi (24.9%), sunsik (17.2%), and hamburgers (10.6%). Among 14 RTC types, the sugars contents were in the order of hot dogs (52.9 g), tteokbokki (30.4 g) and noodles (21.2 g) per package. The percentage of energy from sugars was the highest at 22.9% for sauces, followed by side dishes (17.3%), porridges (14.4%), instant stews (14.3%), and hot dogs (13.1%). Strategies and practices are needed to reduce the sugars contents of HMR producers and the sugars intakes of HMR consumers.

• Journal of Food Hygiene and Safety
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• v.26 no.1
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• pp.25-30
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• 2011

In this study, predictive mathematical models were developed to predict the kinetics of Listeria monocytogenes growth in the mixed fresh-cut vegetables, which is the most popular ready-to-eat food in the world, as a function of temperature (4, 10, 20 and $30^{\circ}C$). At the specified storage temperatures, the primary growth curve fit well ($r^2$=0.916~0.981) with a Gompertz and Baranyi equation to determine the specific growth rate (SGR). The Polynomial model for natural logarithm transformation of the SGR as a function of temperature was obtained by nonlinear regression (Prism, version 4.0, GraphPad Software). As the storage temperature decreased from $30^{\circ}C$ to $4^{\circ}C$, the SGR decreased, respectively. Polynomial model was identified as appropriate secondary model for SGR on the basis of most statistical indices such as mean square error (MSE=0.002718 by Gompertz, 0.055186 by Baranyi), bias factor (Bf=1.050084 by Gompertz, 1.931472 by Baranyi) and accuracy factor (Af=1.160767 by Gompertz, 2.137181 by Baranyi). Results indicate L. monocytogenes growth was affected by temperature mainly, and equation was developed by Gompertz model (-0.1606+$0.0574^*Temp$+$0.0009^*Temp^*Temp$) was more effective than equation was developed by Baranyi model (0.3502-$0.0496^*Temp$+$0.0022^*Temp^*Temp$) for specific growth rate prediction of L.monocytogenes in the mixed fresh-cut vegetables.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.526-533
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• 2019

The purpose of this study was to investigate hazardous microorganisms in mixed baby leafy vegetables and various baby leafy vegetables used as raw materials for fresh-cut produce in spring and summer. To estimate microbial loads, a total of 298 samples including 181 samples of mixed baby leafy vegetables purchased in a Korean market and 117 samples of various baby leafy vegetables from distribution companies were collected. Fecal indicators (coliform and Escherichia coli) as well as food-borne pathogens (E. coli O157:H7, Salmonella spp., Staphylococcus aureus) were enumerated. As a result, the mixed baby leafy vegetable samples showed significantly higher (P<0.05) coliform bacteria numbers in summer (5.59±1.18 log CFU/g) compared to spring (3.60±2.53 log CFU/g). E. coli was detected in 1.3% (1/79) and 42.2% (43/102) of samples collected in spring and summer, respectively. Only one sample collected from a market in spring was contaminated with S. aureus. In the experiment with baby leafy vegetables, the number of coliforms detected in baby leafy vegetables cultivated in soil in spring was 1.15±1.95 log CFU/g, and that in summer was 4.09±2.52 log CFU/g. However, the number of coliforms recovered from baby leafy vegetables cultivated in media was above 5.0 log CFU/g regardless of season. Occurrences of E. coli were 44.4% (12/27) and 19.0% (4/21) for baby leafy vegetables cultivated in soil and media, respectively. However, E. coli O157:H7 and Salmonella spp. were not detected. These results are in relation to microbial loads on mixed baby leafy vegetables associated with raw materials. Therefore, it is necessary to develop and implement hygienic practices at baby leafy vegetable farms to enhance the safety of fresh produce.

• Korean Journal of Food Science and Technology
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• v.49 no.6
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• pp.632-637
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• 2017

This study was conducted to determine the minimal processing characteristics of four vegetables (brown mustard, kale, red beet and red lettuce) for wrapping (Ssam). Prior to evaluation, the vegetable leaves were cut, washed, and packaged. The texture, weight loss, browning index, pH, gas concentrations ($O_2$ and $CO_2$), microbial growth, and organoleptic qualities of the leaves were assessed at $10^{\circ}C$ for 7 days. The cutting strength of red beet was significantly different among leaves. The initial springiness of brown mustard was the lowest (0.98%). The weight loss varied between 0.24 to 4.77%, pH ranged from 6.00 to 6.95, and browning index increased to 0.95 during storage. Changes of gas composition were lower in cut leaf than whole leaf. Aerobic bacteria (4.9-8.0 log CFU/g), yeast (not detected), mold (-3.5 log CFU/g), and total coliforms (5.0-8.0 log CFU/g) were assessed in the samples. Thus, overall quality of kale and red beet leaves with minimal processing showed satisfactory results when stored for 7 days.

• Food Science and Preservation
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• v.22 no.5
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• pp.623-628
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• 2015

Fresh cut vegetables provide convenience and rapidity to consumers. However, they have a weakness with respect to their short shelf-life due to browning and quality degradation via increased respiration. To overcome this problem, the effect of packaging film on the short-term storage of cut kimchi cabbages was investigated. Polypropylene (PP), oriented polypropylene (OPP), and low-density polyethylene (LDPE) films were used as packaging film, and cut kimchi cabbages were stored in the packaging films at $5^{\circ}C$ for 4 weeks. PP film packaging showed the least weight loss and soluble solids loss after 4 weeks. Titratable acidity increased during storage for all samples, however, the increase rate of titratable acidity in PP and OPP film packaging decreased, which was lower than that of LDPE film packaging. Color values decreased over time during storage. In appearance, PP film packaging was better than other films due to their high transparency. In a sensory test, there was no statistical difference among samples. Taken together, the transparent PP film packaging was more effective for short-term storage of cut kimchi cabbages. Thus, this study provides useful information for the selection of packaging materials for cut kimchi cabbage marketing.

• Journal of Food Hygiene and Safety
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• v.31 no.6
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• pp.393-398
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• 2016

The objective of this study was to isolate pathogenic Escherichia coli from fresh vegetables with selective media and Petrifilm, and identify a suspicious colony using biochemical identification. Twenty gram of lettuce, twenty gram of cabbage and ten gram of sprout were prepared, and a 5-strain mixture of pathogenic E. coli (Enterohemorrhagic E. coli NCCP11142, Enterotoxigenic E. coli NCCP14037, Enteropathogenic E. coli NCCP14038, Enteroaggregative E. coli NCCP14039, Enteropathogenic E. coli NCCP15661) was inoculated to obtain 1, 2 and 3 log CFU/g. Eighty to ninety milliliter of buffered peptone water (BPW) was placed and pummeled for 60 s. As a results, the Petrifilm method was all positive, but enrichment method of qualitative analysis was negative except for 3-log CFU/g inoculated lettuce. Regarding biochemical identification of pathogenic E. coli, the identification rates were dependent on type of methods and vegetables; lettuce: API 20E 100% (44/44), Microgen GNA 100% (44/44) and Food System 66.7% (10/15), cabbage: API 20E 64.7% (22/34), Microgen GNA 50% (16/32) and Food System 60% (9/15), sprout: API 20E 65.1% (28/43), Microgen GNA 62.3% (27/43) and Food System 53.3% (8/15). These results could be useful in determining an appropriate method to detect pathogenic E. coli in fresh vegetables.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.1
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• pp.1-10
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• 2016

The purpose of this study was to investigate the need to develop foods for the elderly based on their food preferences. A one-to-one survey method was used for data collection, and the survey was conducted on 165 elderly people (male: 47, female: 118) attending senior welfare centers in Seoul. The results of this study show that the preferred cooking method was steaming rather than stir-frying. Vegetables (4.24), fruits (4.22), Kimchi (3.87), fish (3.83), tofu (3.81), rice-cakes (3.65), dairy products/eggs (3.47), meat (3.45), noodles (3.44), seafood (3.44), poultry (3.23), bread/cookies (3.10) showed high preferences in order (p<0.05). The respondent's chewing & swallowing degree were "Not uncomfortable chew" 31.5%, "Hard food, and a big food is a little difficult to intake". 37%, "Hard food, and a big food is difficult to intake" 11.5%, "Small food, and soft foods can intake" 11.5%, and "It is difficult to intake solid food" 1.2%. Foods that were difficult to chew were meat 28.3%, seafood 15.2%, vegetables 15.2%, nuts 14.1%, fruits 12.0%, Kimchi 8.7%, and other 6.5%. For respondents, the most important factors affecting choice of elderly foods were flavor (48.5%), hygiene (43.0%), and nutrition (36.4%). The elderly wanted "Ready to eat (RTE)" 53.9%, "Ready to heat (RTH)" 15.8%, "Ready to cook (RTC)" 21.2%, and 'Fresh cut product" 9.1%.

• 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.