Predictive modeling of bacterial growth in ready-to-use salted napa cabbage (<i>Brassica pekinensis</i>) at different storage temperatures

Kim, H.W.,Lee, K.,Kim, S.H.,Rhee, M.S. Elsevier 2018 FOOD MICROBIOLOGY Vol.70 No.-

<P><B>Abstract</B></P> <P>The objectives of the current study were to investigate the fate of microbial indicators [aerobic plate counts (APC), total coliforms (TC), and lactic acid bacteria (LAB)] in commercial salted napa cabbages during storage conditions at different temperatures (5, 22, and 30 °C, for up to 72 h) and to develop a predictive growth model using the modified Gompertz equation to determine shelf life. Microbial population sizes (initial log CFU g<SUP>−1</SUP>: APC, 5.1; TC, 3.0; LAB, 3.7) remained stable at 5 °C, but rapidly increased by 2–4 log CFU g<SUP>−1</SUP> within 12 h at 22 and 30 °C; furthermore, the pH of salted napa cabbages decreased significantly (<I>P</I> < 0.05: initial pH 6.3; final pH 4.1–4.4) due to LAB fermentation. The pH showed a negative correlation with all bacterial groups and did not prevent the growth of TC during storage. According to the modified Gompertz model (R<SUP>2</SUP> ≧ 0.97), the highest <I>μ</I> <SUB>max</SUB> was observed for LAB at 30 °C [0.61 log CFU h<SUP>−1</SUP>], while the lowest was noted for TC at 5 °C [0.04 log CFU h<SUP>−1</SUP>]. Shelf-life was determined using APC (7.7 log CFU g<SUP>−1</SUP>) and LAB (6.0 log CFU g<SUP>−1</SUP>) limits; the microbiological acceptability period of salted napa cabbage was predicted to be 12.6 and 9.3 h at 22 and 30 °C, respectively. Thus, consumers should use the product within 12 h of storage at room temperature (more quickly in the summer (9 h)), or store it in a refrigerator. The presented research proposes a shelf-life modeling of commercial salted napa cabbages, which may be used as a scientific basis for product quality control and issuing appropriate guidance for consumer use at home.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A first-ever study of the microbiological shelf life of salted napa cabbage (SNC). </LI> <LI> Bacterial growth data fitted the modified Gompertz model, with R<SUP>2</SUP> ≧ 0.97. </LI> <LI> A decrease of pH on lactic acid fermentation did not inhibit total coliform growth. </LI> <LI> Consumers should use SNC within 12 and 9 h of storage at 22 and 30 °C, respectively. </LI> </UL> </P>

Synergistic bactericidal action of phytic acid and sodium chloride against Escherichia coli O157:H7 cells protected by a biofilm

Kim, N.H.,Rhee, M.S. Elsevier Science Publishers 2016 International journal of food microbiology Vol.227 No.-

<P>The food industry must prevent the build-up of strong Escherichia coli O157:H7 biofilms in food processing environments. The present study examined the bactericidal action of phytic acid (PA), a natural extract from rice bran and the hulls/peels of legumes, against E. coli O157:H7 biofilms. The synergistic bactericidal effects of PA plus sodium chloride (NaCl) were also examined. E. coli O157:H7 biofilms were allowed for form on stainless steel coupons by culture in both rich (tryptic soy broth, TSB) and minimal (M9) medium at 22 degrees C for 6 days. Bacterial cells within biofilms grown in M9 medium were significantly more resistant to PA than those grown in TSB (p < 0.05); thus M9 medium was selected for further experiments. The anti-biofilm effect of PA was significantly increased by addition of NaCl (2-4%) (p < 0.05); indeed, the combination of 0.4% PA plus 3-4% NaCl completely inactivated E. coli O157:H7 biofilms without recovery (a > 6.5 log CFU/cm(2) reduction). Neither PA nor NaCl alone were this effective (PA, 1.6-2.7 log CFU/cm(2) reduction; NaCl, < 0.5 log CFU/cm(2) reduction). Confocal laser scanning microscopy images of propidium iodide-treated cells showed that PA (0.4%) plus NaCl (2-4%) had marked membrane permeabilizing effects. These results suggest that a sanitizer that combines these two naturally occurring antimicrobial agents may be useful to food safety managers who encounter thick biofilm formation in food processing environments. (C) 2016 Elsevier B.V. All rights reserved.</P>

Antagonistic effect of acetic acid and salt for inactivating <i>Escherichia coli</i> O157:H7 in cucumber puree

Lee, S.Y.,Rhee, M.S.,Dougherty, R.H.,Kang, D.H. Blackwell Publishing Ltd 2010 Journal of applied microbiology Vol.108 No.4

<P>Abstract</P><P>Aim: </P><P>This study was conducted to investigate the effects of acetic acid alone or combined with salt for inhibiting <I>Escherichia coli</I> O157:H7 in cucumber puree during storage time at 5 and 22°C.</P><P>Methods and Results: </P><P>Samples at various concentrations were prepared by the addition of acetic acid (0%, 0·25%, 0·5%, 0·75%, 1%, 2%, 2·5%, or 3%) along with NaCl (0% or 3%) and pureed cucumber (50% or 94%). The effect of storage temperature (5 and 22°C) on the survival of <I>E. coli</I> O157:H7 was also tested. The numbers of <I>E. coli</I> O157:H7 were reduced as the amount of acetic acid increased (<I>P </I><<I> </I>0·01) and rate of reduction was more rapid at 22°C than at 5°C. Combinations of acetic acid and salt were less effective at killing <I>E. coli</I> O157:H7 in simulated pickled cucumber samples stored at 5 and 22°C than did treatment of acetic acid alone. The concentration of pureed cucumber affected the reduction rate of <I>E. coli</I> O157:H7. When stored at 5°C, <I>E. coli</I> O157:H7 survived for up to 23 days in a mixture of 94% cucumber puree, 1% acetic acid, and 3% NaCl.</P><P>Conclusions: </P><P>There was the antagonistic effect of acetic acid and 3% NaCl with regard to the reduction of <I>E. coli</I> O157:H7.</P><P>Significance and Impact of the Study: </P><P>Our results suggest that pickled cucumbers prepared with at least 2% acetic acid and stored at room temperature (22°C) after 3 days storage can free from <I>E. coli</I> O157:H7 without heating.</P>

Permalloy/Al₂O₃/Co 접합의 자기터널 효과

이장로,이민숙,송현주,장현숙,김미양,이용호 숙명여자대학교 자연과학연구소 1993 자연과학논문집 Vol.- No.4

1 X 10 -6 Torr의 진공에서 열저항 가열식 진공증착 방법으로 제작한 permalloy/Al₂O₃/Co 강자성 터널접합의 자기저항 효과를 조사하였다. 이 논문에서는 제작한 강자성 터널접합 시료의 전류-전압 특성과 자기 value 효과를 측정하고, 시료진동형자기계로 측정한 자기이력곡선을 통하여 터널저항의 히스테리시스성 자장 의존성을 조사하였다. 터널링은 전류 전압 특성을 측정함으로써 확인 되어진다. 자기저항의 히스테리시스 곡선은 자화의 히스테리시스 곡선과 잘 대응한다. 측정한 자기저항비 △R/R은 실온에서 약 0.6%였다. Magnetoresistance was studied for the ferromagnetic tunneling junction in permalloy/Al₂O₃Magnetoresistance was studied for the ferromagnetic tunneling junction in permalloy/Al₂O₃/Co prepared by evaporation in a vacuum of 1 X 10-6 Torr. We measured voltage-current characteristic and magnetic value effect of prepared ferromagnetic tunneling junction sample. We investigated field-dependency of tunnel resistance by Wheat-stone bridge method and measured magnetic hysteresis curve by vibrating sample magnetometer. The tunneling is confirmed by measuring voltage-current characteristic. The hysteresis curve of magnetoresistance corresponds well with that of magnetization. The magnetoresistance ratio △R/R is 0.6% at room temperature.

항균제 내성 대장균의 생태적 분포 Ⅲ. : Rifampicin, nalidixic acid, oxolinic acid와 sulfa 제제에 관하여

이광호,차창룡,국윤호,최명식,김익상,장우현,이승훈,신정식 대한화학요법학회 1983 대한화학요법학회지 Vol.1 No.1

We studied the differences in the MIC distribution of E. coli isolates, from a doctorless remote arwqwang Won. Do province+WD), a leprosarium (So Rock Do=SRD) and Seoul National University Gospital (SNUH> against rifampicin. nalidixic acid, oxolinic acid &a sulfa drags including co-trinoxawle. . So the widespread and prolonged- use of antimicrobial agents is presumed to facilitate the increase of drng-resistapt strains among the normal flora of the residents in a comunity that .the isolates from SNUH- were further divided into two groups, SNUH in-patient (IP) and SNUH out-patient(OP) and the isolates f p m SRD into DDS (isolates. from.leprosy patients.who are taking DDS only) and R f (isolates from leprosy patients who are taking rifampicin-.and DQS) grougs. Nnmber of, E. coli isolates studied were 93 st;ains from SNUH patients (SNUH-IP, 46; SNUF-OP, 43, 150 strains from SRD patients (SRD-DDS, 102; SRD-Rf,' 48) and 119 strains from 'KWD residents. DisLribntion of E. mli- strains a.mording to thir respective MTC's shows that E. coli possesses not only an intrinsic component in resistance (or susceptibility) to the drugs (rif-ampicin, 2-32 pg/ml; nafii%Xic a,cid, 1-16 pg/d; oxolinic acid, * 0.13-2 pg/ml; DDS, 32-1024 pg/ml; sulfadiazine, 2-256 pg/d, sulfamera&& 4-256 pg/ml; sulfadimethoxine, .16~1024 pg/ml; sdfamonornethoxine, ~-12~,pg&d; sulfamethoxazde, 2-128 pg/m&. trimetk0p-Irim, 0.06-2 pg/fnl; co-trimoxwole, 0,. 25-4 pg/ml) but also distinct MIC values of acquired resistance quite different from the intrinsic ones. The .carriage rate of rifampicin resistant strains in the SRD-Rf patients was the higheest among the study:groups while t m e , of SNUH patients and of the KWD residents were equally negligible, as expectediy. Drug-resistant E. coli strains against nalidixic acid and oxolinic acid were uncommon i n the SNUH, SRD and KWD isolates. However, resistance to sulfa drugs were prevalent in the SNUH, SRD and KWD isolates in the decreasing order. Taken together, these results strongly suggest that drug resistznce in Korea is a localized problem in some community under a high selection pressure of antimicrobial agents rather than a nation-wide one. Trimethoprim resistance gave rise to the high-level resistance 'to co-trimoxazde while the sulfamethoxazole resistance t o the low level resistance against the co-trimoxazole.

Draft genome sequence of Halolamina rubra CBA1107^T, an agarolytic haloarchaeon isolated from solar salt

Lee, M.H.,Lee, H.W.,Song, E.J.,Song, H.S.,Yim, K.J.,Cha, I.T.,Seo, M.J.,Rhee, J.K.,Choi, H.J.,Kim, D.,Kim, K.N.,Roh, S.W.,Nam, Y.D. Elsevier Publishing Services 2014 MARINE GENOMICS Vol.18 No.2

Halolamina rubra CBA1107<SUP>T</SUP> (=CECT 8421<SUP>T</SUP>, JCM 19436<SUP>T</SUP>), an extremely halophilic archaeon, was isolated from non-purified solar salt in the Republic of Korea. H. rubra CBA1107<SUP>T</SUP> shows agarase activity, and its draft genome contains 2955,064bp with a G+C content of 69.0%. This is the first genome that has been sequenced in the genus Halolamina.

A Comparison of Nilvadipine and Diltiazem in the Treatment of Hypertension

Park, D. G 大韓臨床藥理學會 1996 臨床藥理學會誌 Vol.4 No.2

Draft genome sequence of Halorubrum halophilum B8^T, an extremely halophilic archaeon isolated from salt-fermented seafood

Lee, H.W.,Yim, K.J.,Song, H.S.,Nam, Y.D.,Choi, H.J.,Seo, M.J.,Kim, K.N.,Kim, D.,Roh, S.W.,Rhee, J.K. Elsevier Publishing Services 2014 MARINE GENOMICS Vol.18 No.2

The extremely halophilic archaeon, Halorubrum halophilum B8<SUP>T</SUP> (=JCM 18963<SUP>T</SUP>, CECT 8278<SUP>T</SUP>) was isolated from salt-fermented seafood. We report here the draft genome of H. halophilum B8<SUP>T</SUP>, containing 3,677,984bp with a G+C content of 65.1%. The genome consists of 19 genes predicted to encode esterases.

Permalloy/Al₂O₃/Co 접합의 자기터널 효과

이민숙,송현주,장현숙,김미양,이장로,이용호 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.16 No.-

1×10 exp (-6) Torr의 진공에서 열저항 가열식 진공증착 방법으로 제작한 permalloy/Al_2O_3/Co 강자성 터널접합의 자기저항 효과를 조사하였다. 이 논문에서는 제작한 강자성 터널접합 시료의 전류-전압 특성과 자기 valve 효과를 측정하고, 시료진동형자기계로 측정한 자기이력곡선을 통하여 터널저항의 히스테리시스성 자장 의존성을 조사하였다. 터널링은 전류-전압 특성을 측정함으로써 확인 되어진다. 자기저항의 히스테리시스 곡선은 자화의 히스테리시스 곡선과 잘 대응한다. 측정한 자기저항비 ΔR/R은 실온에서 약 0.6 %였다. Magnetoresistance was studied for the ferromagnetic tunneling junction in permalloy /Al_2O_3/Co prepared by evaporation in a vacuum of 1×10 exp (-6) Torr. We measured voltage current characteristic and magnetic valve effect of perpared ferromagnetic tunneling junction sample. We investigated field dependency of tunnel resistance by Wheat stone bridge method and measured magnetic hysteresis curve by vibrating sample magnetometer. The tunneling is confirmed by measuring voltage-current characteristic. The hysteresis curve of magnetoresistance corresponds well with that of magnetization. The magnetoresistance ratio ΔR/R is 0.6% at room temperature.

Pathogenesis and Prevention of Stomach Cancer

Youn, H.-S Korean Academy of Medical Science 1996 Journal of Korean medical science Vol.11 No.5