• Journal of the East Asian Society of Dietary Life
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• v.23 no.5
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• pp.654-661
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• 2013

The current research is designed to analyze sterilization effects on mulberries in terms of storage temperature and storage period after treating with tap water (TW), electrolyzed water (EW) and aqueous chlorine dioxide ($ClO_2$). The treated $ClO_2$ concentrations are 10, 50, 100 and 200 ppm. In each concentration, the mulberries are soaked for 30 seconds respectively. The sterilization effects are being compared at room temperature ($25^{\circ}C$) and at $4^{\circ}C$, respectively. And the enzyme activity related to quality is also being investigated and analyzed about for browning inhibition effects. Microbial sterilizing power increases more in treating plots with EW and $ClO_2$ than treating plot with TW. Futhermore sterilizing power of $ClO_2$ increased sharply on high concentration treatment plot as well. Sterilization effects of $ClO_2$ during storage time are better at cold temperature. Pictures taken from scanning electron microscope reveal that there are no microbes in sterilizing solutions treatment plots. From measurement of the enzyme activity, it is concluded that activities decrease more in sterilizing solutions treatment plots as comparing with TW treated plot during the time. The amount of total polyphenolics decrease with the time passing and EW and $ClO_2$ treatment shows less contents than TW treatment. Thus, EW and $ClO_2$ treatment of mulberris are considered as method to improve safety by reducing total plate count and to contribute to quality maintenance and to extend storage time.

• Microbiology and Biotechnology Letters
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• v.43 no.1
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• pp.31-37
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• 2015

This study was conducted to investigate the bactericidal activity of electrolyzed water (EW) against coliform bacteria on Undaria pinnatifida (UP). The UP was washed with 15% EW, tap water (TW), and distilled water in the following order: 15% EW for 5 and 10 min (1st to 3rd washing process), TW for 1 min, and distilled water for 10 min (3rd to 5th washing process). The washing processes using 15% EW and distilled water occurred a total of 6 times. The number of viable cells, coliform bacteria, and molds in the untreated sample were in the range of 10¹ to 10³ CFU/g. In the case of the UP with 15% EW for 5 min sample, the viable cell counts were reduced by 1-2 log cycles as compared with the untreated sample. The coliform bacteria were not detected except after the 1st EW washing process. Mold counts were not detected in all treatments. In the UP with 15% EW for 10 min sample, the viable cells, coliform bacteria, and mold counts were not detected. In color, there were no significant differences among samples. In sensory evaluation, the UP treated with 15% EW for 10 min (first washing process) got higher scores for color, aroma, and taste than others. These results suggest that the treatment of 15% EW for 10 min is the most effective way to reduce coliform bacteria of the UP.

• Journal of Food Hygiene and Safety
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• v.27 no.3
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• pp.264-270
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• 2012

This study was performed to compared the effectiveness of individual treatments (electrolyzed water: EW, organic acid, and ultrasound) and their combination on reducing foodborne pathogens from perilla leaves. Perilla leaves were innoculated with a cocktail of Salmonella Typhimurium, Staphylococcus aureus, Bacillus cereus. Inoculated perilla leaves were treated with EW combined with different concentration of acetic acid (0.5%, 1.0%, 1.5%, 2.0%) for 1 min at room temperature. Treatment of 3 pathogens on perilla leaves with electrolyzed water combined with ultrasound (25 kHz) and 0.5% acetic acid was also performed for 1 min. While the numbers of S. Typhimurium and B. cereus showed reduced with increasing acetic acid concentration, there is no difference in the number of S. aureus treated with EW containing 0.5% to 1.5% acetic acid. Discoloration was observed the perilla leaves treated with EW combined with more than 1.0% acetic acid. For all three pathogens, the combined treatment of EW and ultrasound resulted in additional 0.42 to 0.72 $log_{10}$ CFU/g. The maxium reductions of S. Typhimurium and B. cereus were 0.95, 1.23 $log_{10}$ CFU/g after treatment with EW combined with 0.5% acetic acid and ultrasound simultaneously. The results suggest that the treatment of EW combined with 0.5% acetic acid and ultrasound increased pathogens reduction compared to individual treatment.

• Korean Journal of Food Science and Technology
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• v.41 no.5
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• pp.578-586
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• 2009

This study was conducted to determine the effects of alkaline electrolyzed water (AIEW), acidic electrolyzed water (AcEW), 1% citric acid, and 100 ppm sodium hypochlorite, either alone or in combination with citric acid, in reducing the populations of spoilage bacteria and foodborne pathogens (Listeria monocytogenes and Escherichia coli O157:H7) on lettuce at various exposure times (3, 5, and 10 min) with different dipping temperatures (1, 20, 40, and $50^{\circ}C$). In addition, the inhibitory effect of alkaline electrolyzed water combined with citric acid on the browning reaction during storage at $4^{\circ}C$ for 15 days was investigated. Compared to the untreated control, electrolyzed water more effectively reduced the number of total bacteria, mold, and yeast than 100 ppm sodium hypochlorite under the same treatment conditions. All treatments exposed for 5 min significantly reduced the numbers of total bacteria, yeast, and mold on head lettuce. The inactivation effect of each treatment on head lettuce was enhanced as the dipping temperature increased from 1 to $50^{\circ}C$, but there was no significantly difference at temperatures greater than $40^{\circ}C$ (p<0.05). The total counts of yeast and mold in head lettuce were completely eliminated when a combination of 1% citric acid and AlEW treatment was used at temperatures greater than $40^{\circ}C$. However, decreased reduction in L. monocytogenes (2.81 log CFU/g), and E. coli O157:H7 (2.93 log CFU/g) on head lettuce was observed under these treatment conditions. In addition, enhanced anti-browning effect was observed when the samples were subjected to both 1% citric acid and AlEW treatment at temperatures greater than $40^{\circ}C$ compared to when single treatments alone were used. Thus, this combined treatment might be considered a potentially beneficial sanitizing method for improving the quality and safety of head lettuce.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.8
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• pp.1296-1303
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• 2014

This study was conducted to develop predictive models for the growth of Bacillus cereus on carrot treated with slightly acidic electrolyzed water (SAcEW) and ultrasonication (US) at different storage temperatures. In addition, the inactivation of B. cereus by US with SAcEW was investigated. US treatment with a frequency of 40 kHz and an acoustic energy density of 400 W/L at $40^{\circ}C$ for 3 min showed the maximum reduction of 2.87 log CFU/g B. cereus on carrot, while combined treatment of US (400 W/L, $40^{\circ}C$, 3 min) with SAcEW reached to 3.1 log CFU/g reduction. Growth data of B. cereus on carrot treated with SAcEW and US at different temperatures (4, 10, 15, 20, 25, 30, and $35^{\circ}C$) were collected and used to develop predictive models. The modified Gompertz model was found to be more suitable to describe the growth data. The specific growth rate (SGR) and lag time (LT) obtained from the modified Gompertz model were employed to establish the secondary models. The newly developed secondary models were validated using the root mean square error, bias factor, and accuracy factor. All results of these factors were in the acceptable range of values. After compared SGR and LT of B. cereus on carrot, the results showed that the growth of B. cereus on carrot treated with SAcEW and US was slower than that of single treatment. This result indicates that shelf life of carrot treated with SAcEW and US could be extended. The developed predictive models might also be used to assess the microbiological risk of B. cereus infection in carrot treated with SAcEW and US.

• Microbiology and Biotechnology Letters
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• v.43 no.1
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• pp.38-44
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• 2015

This study was conducted to investigate the effects of electrolyzed water (EW) and hot-air-drying with ultraviolet light (UV) to reduce coliform bacteria of Undaria pinnatifida (UP). The UP was washed in the order of 15% EW, tap water (TW), and distilled water (DW) under following conditions: 15% EW for 10 min (washing: 1 time), TW for 1 min, and DW for 10 min (washing: 5 times). Viable cells, coliform, and mold counts were at 10²-10³ CFU/g in untreated samples. After EW treatment, viable cells, coliform, and molds were not detected in whole samples or on the surface of UP. But, after hot-air-drying at 48°C for 48 h, the number of viable cells, coliform, and molds were 10¹-10⁵ CFU/g. After hot-air-drying at 48°C for 48 h with UV (12-48 h), viable cells, coliform, and molds were not detected in whole samples or on the surface of UP. In respect of color value, there were no significant changes. In sensory evaluation, the UP with hot-air-drying with UV (12 h) had the highest score in overall preference among UV treatment groups. These results suggest that the treatments at 15% EW for 10 min and hot-air-drying at 48°C for 48 h with UV (12 h) were effective to reduce coliform bacteria of the dried Undaria pinnatifida.

• Food Science and Preservation
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• v.14 no.1
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• pp.8-17
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• 2007

The efficacy of strong acidic electrolyzed water (SAEW) at pH 2.53, with ORP of 1,088 mV and HClO concentration of 91.25 ppm, and low alkaline electrolyzed water (LAEW) at pH 8.756, with ORP of 534 mV and HClO concentration of 105.70 ppm, as storing liquids for peeled potato and sweet potato was evaluated in this study. During storage at $5^{\circ}C$, total phenolic contents and PPO activities of peeled potato and sweet potato stored in SAEW and LAEW were lower than those of control samples stored in tap racer (TW) with 0.85% (w/v) NaCl and 0.5% (w/v) sodium metabisulfite (SMS). Increment in color differences and decreases in hardness of peeled potato and sweet potato stored in SAEW and LAEW were lower than those of controls. Also, SAEW and LAEW inhibited growth of microorganisms for at least 3-6 days of storage. The sensory characteristics of peeled potato and sweet potato stored in LAEW were best during the first half of the storage period, compared to samples preserved by other methods.

• Journal of Biosystems Engineering
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• v.34 no.6
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• pp.446-453
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• 2009

This study was conducted to find condition of improving the quality of peach by using surfacing washing system. The rate of weight loss of A,B groups were showed slower decreasing trend than CT group and the value of soluble solid degree was not different significantly among all groups from the results of stored peach treat with surface washing system of peach in the first experiment. The colory value of surface were increased with increasing storage period in all treatments. Browning pace of A,B groups were slower than control. Emission of carbon dioxide was increased from the results of respiration rate, 6-10 mL/kg/hr $(10^{\circ}C)$ and 32-41 mL/kg/hr $(25^{\circ}C)$. In second experiment with surface washing system of peach, the value of soluble solid was showed with similar value from 10 $Brix^{\circ}$ to 13 $Brix^{\circ}$. The pace of soft rot of EW groups were lower than CT groups from the results of hardness during storage period. The results of colory value was not showed with significant difference in $15^{\circ}C$ and $20^{\circ}C$ storage temperature but changed to browning in EW groups. The moisture contents was from 85% to 90% in all groups. And the count of total microorganism of EW groups were lower than control. Also total coliform of EW groups were negative. In sensory evaluation, washing peach was showed higher value with significant difference in all acceptability.

• Food Science and Preservation
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• v.15 no.2
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• pp.169-173
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• 2008

Bacillus subtilis subsp. subtilis constitutes 90% of the total viable bacteria present on Capsosiphon fulvescens. We found that hydrogen peroxide (50 ppm) and NaOCl (50 ppm) were more effective than electrolyzed water (EW, 50ppm) against B. subtilis subsp. subtilis that was isolated from this seaweed. Relative to a control, 50 ppm hydrogen peroxide reduced the total viable population by $1.8{\pm}0.4$ log CFU/g, whereas 50 ppm EW increased the total viable population by $1.7{\pm}0.5$ log CFU/g. CFUs were evaluated following 30 days of storage at $4^{\circ}C$ using air- and vacuum-packaging. Samples treated with 50 ppm hydrogen peroxide and NaOCl showed a $1.6{\pm}0.1$-fold decrease in initial hardness ($7.9{\times}10^6dyne/cm^2$), while the samples treated with 50 ppm EW had a $2.1{\pm}0.1$-fold decrease in initial hardness ($7.9{\times}10^6dyne/cm^2$). Again, measurements were performed after storage at $4^{\circ}C$ for 20 days. This study indicates that B. subtilis subsp. subtilis is the most common contaminant in aerobically or anaerobically packaged seaweed and should therefore be the main target for quality control during long-term storage. Hydrogen peroxide and NaOCl are more effective than EW in inhibiting B. subtilis subsp. subtilis and in reducing total bacterial loads in air- and vacuum-packaged seaweed.