• Korean Journal of Environmental Agriculture
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• v.36 no.4
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• pp.279-287
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• 2017

BACKGROUND: Many farmers who cultivate the strawberries for export have used agricultural chemicals which MRL (Maximum Residue Limits) of main export target countries or simultaneous multi-residue analysis in Korea have not been established. Among them, the cyenopyrafen and cyflumetofen were selected and applied to this study to determine the PHI (pre-harvest interval) which is appropriate to the PLS (Positive List System) criterion (0.01 mg/kg) and to investigate the residual amounts in the samples. In addition, Fifty pesticides were monitored to check up whether it is suitable or not for main export target countries. METHODS AND RESULTS: Cyenopyrafen and cyflumetofen were spayed out to the strawberries. Samples for residual analyses were taken for maximum 60 days. After sampling, they were extracted by the QuEChERS method and analyzed using the LC-MS/MS. Cyenopyrafen and cyflumetofen were detected in a range of 0.0106~2.6517 mg/kg and of 0.0005~1.4480 mg/kg, respectively. From this results, they were found to be suitable for PLS concentration after 30 or 45 days after spray. In addition, they were detected in most samples that were selected at random. Their concentrations were higher than the PLS criterion in the maximum twenty samples. Twelve of pesticides unsuitable for main export target countries have been detected in the monitoring of simultaneous multi-residue analysis. The result indicates they are unsuitable for export since they excesses over PLS criterion. CONCLUSION: The monitoring result showed it is necessary to establish the pesticide standards of safe use suitable for the PLS criterion. In addition, it is considered continues management and inspection are needed to solve problems caused by unsuitable pesticides in export strawberries.

• Korean Journal of Agricultural Science
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• v.29 no.1
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• pp.24-31
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• 2002

This experiment was conducted to improve the market quality of fresh strawberries through postharvest treatment of $CO_2$ at commercial level. Postharvest application of $CO_2$ increased flesh firmness regardless of ripeness of strawberries. Firmness further increased in berries of full maturity but the actual firmness was higher in less mature berries. The optimal condition of $CO_2$ treatment was above 15% of $CO_2$ for 4 hours during cooling of harvested fruit. Residual effect of firmness increase was remained until simulated shipment as well as retail condition for 1 days at ambient temperature. Market quality of full ripe fruit at harvest significantly reduced due turning skin color to dark red and dryness of physically injured surface. Result indicated that a short term application of $CO_2$ during cooling has a benefit for keeping freshness of strawberries during export and local marketing.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.23 no.2
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• pp.83-87
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• 2017

This study was conducted to determine types of oxygen transmission rate (OTR) films suitable for modified atmosphere (MA) storage treatment of strawberries (cv. 'Maehyang') for export and examination related changes in quality of strawberries during simulated shipping distribution conditions ($2^{\circ}C$ for $10days{\sim}8^{\circ}C$ for 11 days). Strawberries were packed by 1,300, 10,000, 20,000, and $30,000cc/m^2{\cdot}day{\cdot}atm$ OTR films for MA storage treatment and perforated film as the control for MAP. Fresh weight loss rate was less than 0.5% in OTR films except for the perforated film. Carbon dioxide and oxygen content in packages prevailed in permissible range for strawberries under recommended CA/MA conditions (i.e., $CO_2$: 15~20%, $O_2$: 5~10%) at 10,000 cc, 20,000 cc, and 30,000 cc OTR films. Ethylene content in OTR films did not reveal significant differences during storage. The 1,300 cc OTR film revealed highest off-flavor and lowest fungal incidence rate by sensory evaluation. The firmness, soluble solids, and visual quality were preserved the highest at 10,000 cc OTR film. In conclusion, 10,000 cc OTR film preserved the highest quality and extended shelf-life by 13 days if compared with conventional distribution conditions.

• Food Engineering Progress
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• v.23 no.1
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• pp.55-61
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• 2019

For the vessel export of strawberries, modified atmosphere package (MAP) using polyamide (PA) film and linear low density polyethylene (LLDPE) film was investigated to extend the shelf life of strawberries. Because the temperature and relative humidity changes of the MAP were lower than the changes of the control, the weight loss of the MAP were lower than that of the control. The low oxygen level and high carbon dioxide level were effective to decrease the fungal decay rate and to increase the hardness of strawberries. The Hunter's color differences before and after storage showed no distinct difference between the MAP and the control. The lightness had a tendency to decrease while the redness increased. There were no significant changes of the soluble solids during the storage. The shelf life of strawberries could be extended to 16 days using the MAP considering the weight loss and the fungal decay rate. Thus, this MAP method using PA film and LLDPE film was effective to extend the shelf life of strawberries.

• Journal of Food Hygiene and Safety
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• v.31 no.6
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• pp.451-457
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• 2016

The purpose of this study was to determine the antimicrobial effects of $ClO_2$ gas on pathogenic E. coli and Salmonella spp. colonizing on the fruit surface of strawberries for export. Factorial design was employed to treat strawberries inoculated with pathogenic E. coli or Salmonella spp. with a combination of $ClO_2$ gas concentrations (10, 20, 30, 40, and 50 ppmv), RH (50, 70, and 90%), and treatment time (0, 5, 10, 20, and 30 min). Interaction between the factors was observed to note that the reduced levels of microbial population were the highest when RH is set at 90% with gas concentration- and treatment time-dependent manner. With RH and gas concentration fixed at 90% and 50 ppmv, the populations of E. coli and Salmonella spp. decreased by 2.07 and 2.28 log CFU/g when treated for 20 min whereas population reduction by 0.5 and 0.7 log CFU/g were observed when treated for 5 min, respectively. The results help establish most effective conditions for $ClO_2$ gas treatment to enhance microbial safety of strawberries for export.

• Journal of Applied Biological Chemistry
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• v.60 no.4
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• pp.313-319
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• 2017

Strawberries are one of the main commodities in Korea and have been exported over 30 million dollar. And the safety has recently become an important issue in the agro-trade, pesticide residue is most important matter of safe agricultural products. As strawberries can be cultivated using elevated production system, so it is possible to use the drenching. When spraying the pesticides, the use of drenching can be lower amount of residual than using foliar treatment. In this study, time sequential residual amount of pesticides were compared between drenching and foliar application in strawberries. Pesticides were treated with the standard and double dosage and samples were collected at 0, 3, 6, 9, 13, 16 and 21 day and analyzed by LC and LC-MS/MS after liquid-liquid extraction and QuEChERS. Two pesticides were detected less than 1 mg/kg in all samples for drenching treatment. Carbendazim residues in drenching treatment were 5 to 25 times lower than foliar application. And azoxystrobin was not detected in strawberries of drenching treatment.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.626-633
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• 2016

The objective of this study was to assess the effect of precooling and application of gaseous $ClO_2$ on the retention of freshness and quality of 'Maehyang' strawberry fruits intended for export. 'Maehyang' strawberry fruits (Fragaria ${\times}$ ananassa Duch.) were grown in commercial greenhouses and then harvested. Fruits of uniform and medium size at 60% ripeness were selected and assigned to one of four treatment groups: non-treatment (control), precooling only (PO), gaseous $ClO_2$ only (GCO) or precooling combined with gaseous $ClO_2$ (P + C). Weight loss was lowest in the PO treatment and greatest in the GCO treatment after export. Compared to the control and PO treatment groups, strawberry fruits in the GCO treatment group maintained high brightness and high chroma. Six days after shipping, fruits in the P + C treatment group had the highest soluble solids content, even as high as $10.05^{\circ}Brix$; the lowest value was observed in the PO treatment. The incidence rate of gray mold in strawberry fruits was 20% and 17% in the control and the PO treatment, respectively; in the GCO treatment, the incidence rate of gray mold amounted to 10%. No gray mold was observed in the P + C treatment group. These results indicate that gaseous $ClO_2$ treatment combined with precooling (P + C) was effective in maintaining the freshness of 'Maehyang' strawberry fruits intended for export from South Korea to Hong Kong.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.153-160
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• 2020

This study was conducted out to investigate the effect of harvest time of the day, precooling or not, and temperature of precooling and storage on the marketability in strawberries 'Maehyang' for export in May. Strawberry colored with 60±5% of the skin was harvested at 07:00 am or 15:00 pm, respectively. After harvesting, some strawberries were precooled to 0, 2, 4℃ for 3 hours in the cold store, respectively, and the others were kept at room temperature. And then, strawberries were stored at low temperature in the cold store set at 4, 8 or 10℃ storage temperatures. The weight loss rate, firmness, soluble solids content, color, incidence of gray mold of strawberries were measured at two days intervals during storage for 14 days. Both 07:00 am and 15:00 pm harvest, fruits as the storage periods lapses increased weight loss rate compared to the weight at harvest time of the day, and the difference in the weight loss rate of fruits depending on the treatment was greater at 15:00 pm harvest than at 07:00 am. Firmness tended to increase again after 8th day at 07:00 am or 15:00 pm harvest, respectively. In the afternoon harvest, 10℃ storage without precooling showed the lowest fruit firmness on the 2nd day after storage. The soluble solids content at 07:00 am or 15:00 pm harvest tended to be maintained at high value with precooled and stored at low temperature as storage days elapse. The color values were significantly higher at 'L' indicating brightness and lower at 'a', indicating redness at low storage temperature regardless of harvesting time of the day and whether it was precooling or not. The incidence of gray mold was higher at 15:00 pm harvest than at 07:00 am harvest, and it was significantly higher in the treatments stored at 10℃ after precooling similarly. In this study, strawberry 'Maehyang' for export harvested at 07:00 am and stored at 4℃ after precooling at 0℃ maintained the best shelf life, therefore, it is judged that desirable to harvest in the morning with low temperature and to precool and store at low temperature.

• Food Science and Preservation
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• v.24 no.3
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• pp.351-360
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• 2017

We have studied the technology to extend the storage period of 'Seolhyang' strawberries using modified atmosphere package (MAP) and ethyl pyruvate (EP) treatment for domestic distribution and export. The selected ripe strawberries harvested on December 28, 2016 at the Sancheong farmhouse were transported to the laboratory for 2 h and tested. After a day's precooling at $4^{\circ}C$, the strawberries were divided into seven experimental groups. These groups were control, active MAP using low density polyethylene (LDPE), active MAP using polyamide (PA), active MAP using PA with EP treatment, passive MAP using LDPE, passive MAP using PA and passive MAP using PA with EP treatment. Quality analysis was carried out every 4 days during the storage period of 16 days. During the storage period of 16 days, MAP decreased from 3.5% to less than 1.1% in weight loss ratio compared with control, and decreased from 36% to less than 7% in fungal incidence. In the case of fungi in the EP treatment group, hyphae did not grow on the outside of the strawberry but grew to the inside. This tendency was similar to that in the low oxygen and high carbon dioxide environment of the MAP, the mycelium of the fungus did not grow outside of the strawberry. Fungi are the biggest problem in the distribution and export of strawberries, and these results suggest that MAP alone could inhibit mold and increase shelf life.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.366-371
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• 2010

A study was conducted to examine the effect of precooling (2, 4, or $8^{\circ}C$) and storage (4, 8, or $10^{\circ}C$) temperatures on the storage life of 'Maehyang' and 'Soogyeong' strawberries for export. Fruits at a 70% ripe stage were harvested from a commercial greenhouse in Jinju on March 16, 2010. Fruits were precooled by a forced draft cooling for 3 hours, transported for about 30 minutes to a lab., and then stored. For precooling, small precoolers set in the farm were used. During storage, fruits were examined for their changes in weight, hardness, color (hunter value), soluble solid content, incidence of gray mold (Botrytis cinerea), and marketability at a two days interval from March 16 to March 30. In both cultivars, hardness, sugar content, and hunter value were higher in 'Soogyeong' than 'Maehyang'. The greatest hardness and soluble solid content were obtained after storage at $4^{\circ}C$ in both cultivars. As the ripening stage progressed, hardness and soluble solid content decreased. Also, fresh weight decreased during storage at all temperatures. Gray mold was the greatest at $10^{\circ}C$ storage temperature. The results indicate that effectiveness for keeping the freshness was best achieved by precooling at $2^{\circ}C$ and storage at $4^{\circ}C$ in both cultivars.