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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Korean Journal of Food Science and Technology
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Journal DOI :
Korean Society of Food Science and Technology
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Volume & Issues
Volume 45, Issue 6 - Dec 2013
Volume 45, Issue 5 - Oct 2013
Volume 45, Issue 4 - Aug 2013
Volume 45, Issue 3 - Jun 2013
Volume 45, Issue 2 - Apr 2013
Volume 45, Issue 1 - Feb 2013
Selecting the target year
Evaluation of Residual Pesticides in Commercial Agricultural Products Using LC-MS/MS in Korea
Lee, Hwa-Mi ; Hu, Soo Jung ; Lee, Hyun-Sook ; Park, Seung Young ; Kim, Nam-Sun ; Shin, Yong Woo ; Choi, Keun Hwa ; Kim, Sung Il ; Nam, Seul Yi ; Cho, Dae Hyun ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 391~402
DOI : 10.9721/KJFST.2013.45.4.391
Pesticide residues in agricultural products in Korea were evaluated to create a data base to inform food policy. Pesticide residues were investigated in 17 commodities collected from 9 provinces in 2012. Our analytical method of multiresidue analysis, involved the analysis of individual recovery, linearity, limit of detection, and limit of quantitation of 60 pesticides in six matrices. The pesticides, including acetamiprid and forchlorofenuron, were evaluated in 358 agricultural samples by liquid chromatography/tandem mass spectrometry. Twenty three pesticides were detected from 67 samples. The results showed that the ratio of estimated daily intake to acceptable daily intake was 0.00009-0.0861% by the intake assessment, which means that residual pesticides in agricultural products in Korea are properly controlled.
Composition and Antioxidant Activity of Dried Laver, Dolgim
Oh, Sujeong ; Kim, Jeongin ; Kim, Hyangsuk ; Son, Soojeong ; Choe, Eunok ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 403~408
DOI : 10.9721/KJFST.2013.45.4.403
The composition and antioxidant activity of three kinds of dried laver were compared (ondolgim, bandolgim, and paraegim). Dolgim was high in protein (>35%), carbohydrates (>41%), and minerals (>7.5%). Lipid content in dolgim was very low (<1%); eicosapentaenoic acid was the most abundant fatty acid. There were higher levels of carotenoids than phycobilin in dolgim, and chlorophyll among pigments was present at the least amount. Porphyran content was high (>110 g/kg), while tocopherol content was very low (<12.0 mg/kg). Ondolgim had the lowest levels of carotenoids, phycobilin, and chlorophyll, however, polyphenol content was higher in ondolgim. The antioxidant activity was the same among the three kinds of dolgim, and both water and a 20% ethanol extract of dolgim showed higher antioxidant activity than did a 100% ethanol extract. The results suggested that dried laver dolgim was a good food and that all varieties provided both food and health functionality.
Determination of Post-harvest Fungicide in Citrus Fruits Using LC-MS
Choi, Su-Jeong ; Kim, Eun-Jeong ; Lee, Jae-In ; Cho, In-Soon ; Park, Won-Hee ; Hwang, In-Sook ; Kim, Moo-Sang ; Kim, Gun-Hee ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 409~415
DOI : 10.9721/KJFST.2013.45.4.409
Post-harvest fungicide residue was measured in citrus fruits. Samples were collected from local markets in Seoul and analyzed using liquid chromatography coupled with mass spectrometry (LC-MS). LC-MS results were validated for the assay of pesticides by using linearity, accuracy, precision, and limits of detection and quantification. The linearity in the concentration ranged from 0.005 to 2.0 mg/kg (
>0.999). Sample recoveries ranged from 80.2 to 98.3% with relative standard deviations below 4.0% for spiking levels from 0.01 to 1.0 mg/kg. The limits of detection ranged between 0.002 and 0.008 mg/kg, and the limits of quantification ranged between 0.006 and 0.027 mg/kg. The highest residue levels for carbendazim, thiabendazole, imazalil, and azoxystrobin in citrus fruits were 0.541, 0.958, 0.721, and 0.052 mg/kg, respectively. The pesticide residues found in citrus fruits were blow maximum residue limits (MRLs) and are not a serious public health problem.
Stability of the Anthocyanin Pigment Extracted from Aronia (Aronia melancocarpa)
Hwang, Eun-Sun ; Ki, Kyong-Nam ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 416~421
DOI : 10.9721/KJFST.2013.45.4.416
The purpose of this study was to investigate the effects of pH, temperature, light, sugars, and organic acids on the stability of anthocyanin pigments extracted from aronia (Aroniamelanocarpa). Pigments from aronia were most stable at pH 3.0, with maximal absorbance at 514 nm. High temperatures and prolonged heating substantially reduced anthocyanin contents. Anthocyanin levels were as low as approximately 21.70 and 79.63% of normal levels after 300 min of heating at 30 and
, respectively. All of the sugars tested decreased the abundance of aronia pigments, with the levels highest in the presence of maltose, and decreasing progressively in the presence of galactose, sucrose, glucose, and fructose. Among the organic acids tested, citric acid was the most effective in stabilizing the aronia pigment, followed by tartaric acid, malic acid, formic acid, and ascorbic acid. These results provide useful reference data for efforts to use pigments from aronia in processed foods or for developing natural food colorants.
Physicochemical Properties of Black Doraji (Platycodon grandiflorum)
Lee, Soo-Jin ; Shin, Seung-Ryeul ; Yoon, Kyung-Young ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 422~427
DOI : 10.9721/KJFST.2013.45.4.422
The physicochemical properties of raw and black doraji were examined with the goal of increasing the utilization of doraji. Raw and Black doraji contained similar amounts of crude ash, crude fat, and crude protein, but raw doraji had higher level of fiber. Arginine was the major free amino acid in both types of doraji. Free sugar and organic acid contents of doraji increased after steaming heat treatment. Potassium was a prominent mineral in both raw and black doraji, constituting 85% of total minerals. Black doraji contained almost twice as much crude saponin as did raw doraji. Black doraji showed lower values of L (lightness), a (redness), and b (yellowness). The hardness and chewiness of raw doraji were higher than those of black doraji. Black dorai showed a higher amount and extraction rate of saponin, even though nutrient value of doraji slightly decreased after steaming heat treatment. Therefore, black doraji can be a valuable ingredient in functional foods.
Physicochemical Characteristics of Galactomannan by Fractionation to Evaluate Heterogeneity
Kim, Kyeong-Yee ; Lee, Eun-Kyung ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 428~433
DOI : 10.9721/KJFST.2013.45.4.428
Heterogenous samples of locust bean gum (galactomannan) were prepared into homogeneous substances. Locust bean gum was fractioned using ammonium sulfate (14.11-23.08%, w/w). The intrinsic viscosity was obtained by extrapolating reduced viscosity versus concentration by using an Ubbelohde viscometer. The ranges of intrinsic viscosity for fractions that not included protein (F3-F6) and fractions that included protein (F1-F2) were 9.89-8.10 and 8.44-4.59, respectively. Values for Huggins' coefficient (k'), which depends on physical interactions, were 0.46-0.78. Increasing ammonium sulfate concentration was associated with a weak trend towards lower molecular weight and intrinsic viscosity by size-exclusion chromatography (SEC):
ranged from 674 to 617 kg/mol and [
] from 9.80 to 8.10 dL/g between F3 and F6. The evaluations of those fractions by using SEC and the Ubbelohde viscometer produced very similar values, as predicted. We verified the application of a gradient of ammonium sulfate to precipitate locust bean gum into fractions of different molecular size and show structural variations.
Physicochemical Characteristics of Cheonnyuncho Fruit (Opuntia humifusa) Fermented by Leuconostoc mesenteroides SM
Park, Min-Ju ; Lee, Sam-Pin ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 434~440
DOI : 10.9721/KJFST.2013.45.4.434
Functional properties of Cheonnyuncho fruit paste (CFP) were enhanced by fermentation, using Leuconostoc mesenteroides SM. The stability of CFP pigment was maintained and microorganisms in crude CFP were sterilized by heating at
for 30 min. The production of dextran in CFP was increased by increasing the fermentation time and sugar content, resulting in an increase of consistency. The CFP fermented with 20% sucrose contained 4.8% mucilage after fermentation for 2 days. In particular, the production of mucilage was greatly enhanced by fortification with 3% sodium citrate in CFP, resulting in mucilage production of 7%. In addition, the viscous modulus of fermented CFP showed a greater increase than that of the elastic modulus. Thus, it was concluded that CFP fermented by L. mesenteroides SM can be fortified with functional ingredients, such as mucilage and probiotics, with enhanced rheological properties. Therefore fermented CFP can be utilized as the functional ingredients for functional foods.
Optimization of the Preparation of Domestics Wheat Cookies by Addition of Red Radish (Raphanus sativus L.) Sprout Powder
Cheon, Chun Jin ; Kim, Young-Ho ; Oh, Jong Chul ; Kim, Jin Kon ; Yu, Hyeon Hee ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 441~450
DOI : 10.9721/KJFST.2013.45.4.441
The purpose of this study was optimization of the conditions for mixing different amounts of red radish (Raphanus sativus L.) sprout powder, butter, and sugar when baking domestic wheat cookies prepared using red radish sprout powder. Response surface methodology, with a central composite design comprising 5 levels and 3 variables, was used to identify the best possible combination of amounts of red radish sprout powder (
), butter (
), and sugar (
). The physical and mechanical properties of each of the 20 samples analyzed, including color L (p<0.001), color a (p<0.01), color b (p<0.001), spread ratio (p<0.001), and hardness (p<0.01), differed significantly. The results of sensory evaluations, including color (p<0.001), appearance (p<0.001), texture (p<0.001), flavor (p<0.01), taste (p<0.001), and overall quality (p<0.001) also differed significantly among the samples. The optimal compositional ratios were 5.15 g for the red radish sprout powder, 64.84 g for the butter, and 47.18 g for the sugar.
Physico-chemical Characteristics of Black Raspberry Fruits (Bokbunja) and Wines in Korea
Lee, Seung-Joo ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 451~459
DOI : 10.9721/KJFST.2013.45.4.451
Korean black raspberry fruits (bokbunja) were collected from 11 different producing regions, and commercial black raspberry wines were obtained from 24 manufacturers. Samples were analyzed for soluble solids, titratable acidity, pH, reducing sugar content, hunter color values, intensity, hue, total phenolic content, and organic acids. The fruit samples showed similar pH levels (3.43-3.52), but significantly differed in total acidity levels (9.98-16.2 g/L). The predominant organic acids in the fruit samples were citric acids (1.39-5.63 mg/mL) and succinic acids (0.25-6.53 mg/mL). Among the samples, black raspberry fruits from Goksung and Nonsan showed the lowest levels of total phenolic content, and the lowest values in intensity. The fruits from Jeongeup and Sunchang showed higher levels of phenolic content, soluble solids, and intensity. Some wine samples, including BH, KO, SR, and SE, showed overall high levels of phenolic content, organic acids like citric and succinic acid, and color values such as
, and intensity. Other wine samples, including DW, SC, GJ, and NB, were high in acetic acid, color values like
, and hue.
Preparation of Garaedduk with Buckwheat Flour Using Retrogradation-retardation Technology
Lee, Jun Woo ; Bae, In Young ; Oh, Im Kyung ; Kim, Myung Hwan ; Han, Gwi Jung ; Lee, Hyeon Gyu ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 460~465
DOI : 10.9721/KJFST.2013.45.4.460
Garaedduk made with various levels of buckwheat flour (0, 15, 30, and 45%) for rice flour was prepared using retrogradation-retardation technology and their physical and sensory properties were investigated. The moisture content of garaedduk decreased and the color differences increased as the ratio of buckwheat flour to rice flour increased. During storage at
, the hardness values of garaedduk made with 15 and 30% buckwheat flour were maintained for up to three days. Immediately after manufacture, garaedduk made with higher levels of buckwheat flour had reduced overall acceptability. However, there was no significant difference in the overall acceptability of garaedduk made with 0 and 15% of buckwheat flour after storage. Therefore, buckwheat flour can replace rice flour with retrogradation-retardation technology to inhibit the starch retrogradation of garaedduk, which maintained its overall quality at a buckwheat flour level of 15%.
Effect of Different Pre-treatments on the Physicochemical and Antioxidant Activities of Cold-Vacuum Dried Peaches
Kwon, Gi-Man ; Kim, Jae-Won ; Youn, KwangSup ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 466~472
DOI : 10.9721/KJFST.2013.45.4.466
This study was performed to determine the effects of the pretreatment and cold-vacuum drying methods on the physicochemical properties and antioxidant activities of dried peaches. Moisture content was significantly lower with 0.3% NaCl treatment with cold-vacuum drying. The pH, brix and acid ratio (SS/TA) were the lowest with 1.0% soluble Ca treatment, while soluble solid and SS/TA were significantly higher with 0.1% vitamin C treatment compared to those with other treatments. The
and browning degree was lower in the pretreated sample compared to the untreated sample. Cutting strength of dried peaches was highest in the pretreated samples, and it was the highest with 1.0% soluble Ca treatment. Total sugar content with 0.1% vitamin C and 1.0% soluble Ca treatment was significantly higher than that with 0.3% NaCl treatment. The free sugar content was lower with 0.3% NaCl treatment but it was higher with 0.1% vitamin C and 1.0% soluble Ca treatment. The sensory evaluation result was highest with 0.1% vitamin C treatment. Phenolic compounds and antioxidant ability were the highest with the 0.1% vitamin C and 0.1% soluble Ca treatment; all the dried peaches showed relatively high antioxidant activities. These results suggest that pretreatment can affect the quality of dried peaches, showing that cold-vacuum drying can be applied for the production of high quality dried peach products.
Determination of the Optimal Mixture Ratio for Extrudates of Job's-tear and Wheat Flour by Mixture Design Analysis
Cho, Seok-Cheol ; Kang, Byung-Sun ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 473~477
DOI : 10.9721/KJFST.2013.45.4.473
The aim of this study was to identify the optimal ingredient-mixing ratio of Job's-tear and wheat flour subjected to extrusion. A modified distance-based mixture design analysis was chosen for the experimental design. The results showed that the bending failure force, the a-value, and the water absorbtion index (WAI) value had no correlation with the mixture ratio of Job's-tear and wheat flour. However, the diameter of the extrudates, the L- and b-values, and the water solubility index (WSI) value were all found to be correlated to the mixture ratio. While the first three values were determined using a linear model, the WSI value was determined using a quadratic model. The diameter and color had an inverse correlation to the mixture ratio: the higher the ratio of Job's-tear to wheat flour, the lower the diameter and darker the color. The L- and b-values were found to change in accordance with the mixture ratio of Job's-tear to wheat flour. The lowest WSI value was obtained at a 40:60 ratio of Job's-tear to wheat.
Influence of the Number of Sulfur Applications on the Improvement of the Chemical Composition and Quality of Onions
Choi, Bogyoung ; Surh, Jeonghee ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 478~487
DOI : 10.9721/KJFST.2013.45.4.478
Onions were treated with different amounts of sulfur (S) during cultivation and examined for their physicochemical properties and flavor. Onions cultivated without S application were the control group; the treatment groups were grown in soil that had been pretreated with S and received additional S applications or four times before harvest. As the number of S applications increased, the levels of crude protein, quantified with total nitrogen; ash, approximating total amounts of minerals; and dietary fiber of the onions tended to increase. The mineral compositions also improved, with noticeable increases in the levels of Mg, K, Fe, and Zn. In particular, the reducing capacity of the onions increased appreciably (p<0.05), without increases in the levels of S-containing compounds such as thiosulfinate or S-containing amino acids. Nevertheless, the spicy hot taste and flavor, which is generated mainly from S-containing compounds, were perceived more strongly in the onions that had received more S applications.
Anti-diabetic Effects of Fermented Green Tea in KK-A
Lee, So-Young ; Park, So-Lim ; Nam, Young-Do ; Yi, Sung-Hun ; Lim, Seong-Il ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 488~494
DOI : 10.9721/KJFST.2013.45.4.488
The anti-diabetic effect of green tea fermented by cheonggukjang was evaluated using KK-
mice, an animal model of type 2 diabetes mellitus. Over a 90 day testing period, food and water intake decreased significantly in the group fed fermented green tea (FGT) and a group fed commercially available health functional food (PC), when compared with a diabetic control group (DC). The blood glucose levels of FGT mice were lower than in DC mice throughout the test period and were similar to the levels in PC after 60 days. Levels of Hemoglobin A1c (HbA1c) levels and insulin resistance were lower in mice of the FGT group than in mice of the DC group. DNA microarray analysis showed that administration of FGT increased the abundance of 12 mRNA transcripts related to diabetes. Whereas FGT increased hexokinase transcripts related to glycolysis more than 37 fold, levels of Pdx1 (pancreatic and duodenal homeobox1) and Cacna1e (calcium channel) transcripts increased more than 1.8 fold.
Antimicrobial Activity of Psoralea corylifolia, Schisandra chinensis, and Spatholobus suberectus Extracts
Choi, Eun-Jeong ; Jang, Sung-Ran ; Kang, Ok-Ju ; Bang, Woo-Suk ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 495~500
DOI : 10.9721/KJFST.2013.45.4.495
This study was performed to identify safe natural food preservatives from medicinal herbs and to evaluate the antimicrobial effects of medicinal plants against microorganisms. Medicinal herbs were extracted 3 times with methanol at
for 3 h and fractionated with n-hexane. The antimicrobial effects of the fractions were determined by measuring the diameter of the inhibition zone by using an agar-well diffusion assay. The MIC of fractions for the inhibition of microorganisms was determined using a microplate reader. The antimicrobial effects of fractions were greater against gram positive bacteria than against gram negative bacteria, but the difference was not significant. The antimicrobial effects of fractions were concentration dependent. While these results have implications, the underlying mechanisms of microbial inactivation need to be further elucidated. The results showed the possibility of developing safer food preservatives.
Optimal Extraction Conditions to Produce Rosemary Extracts with Higher Phenolic Content and Antioxidant Activity
Lee, Chang-Yong ; Kim, Ki-Myeong ; Son, Hong-Seok ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 501~507
DOI : 10.9721/KJFST.2013.45.4.501
We evaluated the effects of temperature, time, solvent type, and solvent concentration on the phenolic content and antioxidant activity of rosemary extracts. The antioxidant capacity of rosemary extracts was demonstrated by their ability to scavenge stable free radicals, and the phenolic content of the extracts was determined using the Folin Ciocalteu method. The highest values were obtained by water-based extraction at
for 30 min, a 75% methanol solution at
for 30 min, and a 50% ethanol solution at
for 10 min. The aqueous solution of 75% methanol, extraction temperature of
, and extraction time of 30 min were the most efficient parameters for the extraction of polyphenols from dry rosemary.
T-lymphocyte Inactivation and Anti-atopic Effects of Diarylheptanoid Hirsutenone Isolated from Alnus japonica
Lee, Do Ik ; Seo, Seong Jun ; Joo, Seong Soo ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 508~514
DOI : 10.9721/KJFST.2013.45.4.508
2Department of Marine Molecular Biotechnology, College of Life Science, Gangneung-Wonju National University Recently, we reported that diarylheptanoid hirsutenone (HST) effectively inactivated T lymphocytes. However, it has not been evaluated whether HST is involved in calcineurin or calmodulin inactivation. In the present study, cells were treated with T-cell inhibitors with or without HST. Our results revealed that HST successfully inhibited expression of T-helper type I (Th1) and Th2 cytokines. Co-treatment with HST and nuclear factor-activated T cell (NFAT) activation inhibitor III (INCA-6) showed a more sensitive effect than that with other inhibitors, suggesting that HST contributes to inhibition of dephosphorylation of NFAT in the cytosol. HST up-regulated cell cycle arrest genes and inhibited the growth of Staphylococcus aureus. These effects were confirmed in an NFAT electrophoretic-mobility shift assay via successful inhibition of NFAT translocation and in the histological recovery in a 2,4-dinitrochloro benzene-induced in vivo model. Taken together, HST was shown to effectively inhibit T-cell activation via inhibition of cytosolic NFAT dephosphorylation, similar to INCA-6.
Denaturing Gradient Gel Electrophoresis and Culture-based Analysis of the Bacterial Community in Cheonggukjang, a Korean Traditional Fermented Soybean Food from Gangwon Province
Hong, Sung Wook ; Lim, In Kyu ; Kim, Yong Woo ; Shin, Seung-Mee ; Chung, Kun Sub ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 515~520
DOI : 10.9721/KJFST.2013.45.4.515
Bacterial communities derived from cheonggukjang and raw rice straw collected from a Mireuksan farm and a Heungup cheonggukjang in Gangwon province were investigated using both culture-based method and denaturing gradient gel electrophoresis (DGGE) analysis. Pure cultures, which were isolated from raw rice straw and cheonggukjang and cultured on tryptic soy agar plates (53-76 colonies per plate), were identified by analysis of 16S rRNA sequences. The traditional culture-based method and analysis of PCR-amplified 16S rRNA by DGGE revealed that for samples collected from the Mireuksan farm, Pantoea agglomerans and Bacillus subtilis were the predominant species in the raw rice-straw and cheonggukjang, respectively. For samples collected from the Heungup cheonggukjang, Bacillus amyloliquefaciens was the predominant species in both raw rice straw and cheonggukjang. Other microorganisms, including members of Pantoea, Bacillus, Enterococcus, Enterobacter, Pseudomonas, Rhodococcus, and Acinetobacter, were also present in the raw rice-straw and cheonggukjang, as were bacteria that could not be cultured.
Quality and Antioxidant Activity of Wet Noodles Supplemented with Non-glutinous Sorghum Powder
Kim, Hyun Young ; Ko, Jee Yeon ; Kim, Jung In ; Jung, Tae Wook ; Yun, Hong Tae ; Oh, In Seok ; Jeong, Heon Sang ; Woo, Koan Sik ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 521~525
DOI : 10.9721/KJFST.2013.45.4.521
In this study, we investigated the physicochemical characteristics of wet noodles that had been fortified by adding non-glutinous sorghum (Sorghum bicolor L. Moench cv. Donganme) powder (SP). The wet noodles were evaluated for quality characteristics, total contents of polyphenols and flavonoids, and capacities to scavenge free radicals. The weight, volume, capacity to absorb water, and turbidity of the cooked noodles differed considerably from the unfortified control. The L- and b-values of the cooked noodles differed significantly between the treatment types, and the a-value increased significantly with increasing concentrations of SP. The tension of the cooked noodles decreased significantly with decreasing concentrations of SP. Total polyphenol and flavonoid contents, as well as free radical-scavenging activities increased significantly with increasing concentrations of SP. In conclusion, SP could be used as an ingredient to increase the sensory and antioxidant properties of wheat flour noodles without affecting their quality.
Effects of the 461-nm LED Light and Combination with Acid Stress Treatment on Staphylococcus aureus and Escherichia coli
Kim, Se-Hun ; Bang, Woo-Suk ;
Korean Journal of Food Science and Technology, volume 45, issue 4, 2013, Pages 526~529
DOI : 10.9721/KJFST.2013.45.4.526
This study was conducted to evaluate the disinfection effects of Staphylococcus aureus, and Escherichia coli treated with 461-nm LED and pH 5 at
for 10 h. S. aureus strains were decreased by about 4 log CFU/mL after 461-nm LED irradiation treatment alone for 10 h. E. coli strains were inactivated by irradiation. However, when microorganisms were subjected to a combined treatment of 461-nm LED and pH 5, both strains were inactivated by irradiation for 7 h. The highest D-value was 5.05 h for S. aureus ATCC 27664 and the lowest D-value was 1.39 h for E.coli O157: H7 ATCC 35150 (p<0.05) with 461-nm LED irradiation. For the combined treatment (461-nm LED and pH 5), the highest D-value was 1.58 h for S. aureus ATCC 19095, whereas the lowest D-value was 0.83 h for S. aureus ATCC 27664 (p<0.05). These data showed that bactericidal effects of a combination of pH 5 with 461-nm LED irradiation were enhanced compared to 461-nm LED irradiation alone.