• Title, Summary, Keyword: USDA method

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Isolation and Characteristics of Listeria monocytogenes from Frozen Foods in Korea (국내에서 판매되는 냉동식품으로부터 Listeria monocytogenes의 분리 및 특성조사)

  • Chang, Yun-Hee
    • Korean Journal of Food Science and Technology
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    • v.31 no.5
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    • pp.1324-1329
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    • 1999
  • This study was carried out to investigate the distribution and characteristics of Listeria monocytogenes isolated from frozen Mandoo and pizza in 1998. A total 72 samples were examined and USDA, FDA and modified cold enrichment methods were used for the detection of Listeria spp. Overall prevalence of L. monocytogenes in frozen foods was 9.7% and L. monocytogenes was isolated from 11.1% of frozen Mandoo and 5.6% of frozen pizza. The highest detection rate of Listeria spp. in frozen Mandoo was found at USDA method and the serotype of L. monocytogenes isolates was 4. Isolated L. monocytogenes was confirmed by PCR method with Hly 1 and 2 as primers. It would be necessary to develop more rapid and specific method to isolate and confirm L. monocytogenes from foods because USDA and PCR methods used in this study took 3-4 days. D value of L. monocytogenes isolate in tryptic soy broth was 49.2 sec at $60^{\circ}C$ and 8.8 sec $at\;65^{\circ}C$, and D value of L. monocytogenes in foods with high distribution rate of Listeria spp. would be necessary to evaluate for the safe use of frozen foods.

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Marker-Exchange Mutagenesis of Pectate Lyase Gene in Rhizobium fredii (Rhizobium fredii Pectate Lyase 유전자의 Marker-Exchange 변이)

  • 정민화;박용우;윤한대
    • Microbiology and Biotechnology Letters
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    • v.19 no.3
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    • pp.222-227
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    • 1991
  • Rhizobium fredii USDA193 is one of the causal organism for root nodule formation in soybean (peking). Previously we cloned the pectate lyase gene (SY1) of R. fredii USDA193. The $pel^-$ mutants (SY1$\Omega$ and SY1$\Omega$1) of SY1 were obtained using the in vitro insertional omega mutagenesis of RpelB (of Rhizobium pel) and fill-in reaction of RpelE (of Rhizobium pel) gene respectively, and we constructed two mutants (R, fredii USDA193$\Omega$ and R. fredii USDA193$\Omega$1) in pectate lyase function by marker-exchange with pe1B::$\Omega$ and R. fredii USDA193 strain (rif). The pectate lyase activity of two pel- mutant of R. fredii USDA193 was determined by spectrophotometric method. However, all pectate lyase activity of these mutants was not lost upon the mutagenesis by marker-exchange. This suggests that other pectate lyase genes may be present on the plasmid or the chromosome of R. fredii. As yet we do not have evidence linking RpelB and RpelE genes of R. fredii directly to the early nodulation process.

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Contamination of Listeria spp. in Market Beef (국내 시판 쇠고기의 Listeria spp. 오염)

  • 구동환;정충일;정동관;남은숙
    • Journal of Food Hygiene and Safety
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    • v.10 no.2
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    • pp.89-95
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    • 1995
  • Highly lethal Listeria monocytogenes, causing bromatoxism through vegetables, dairy products, meat products and shellfish etc, was examined for possible contamination in market beef. USDA, FDA, Malthus and Modified Cold Enrichment methods were used for the detection of Listeria spp.. Samples of domestic and imported market beef were collected from local meat shopsat Seoul, Korea. Total two hundreds and six of Listeria spp. were isolated and identified from beef. Among 206 isolates, the number of L. welshimeri was one hundred and twenty-one(44.8%). The numbers of isolated L. innocua, L. murrayi, L. monocytogenes, L. grayi, L. seeligeri, and L. ivanovii were 49(18.1%), 14(5.2%), 12(4.4%), 6(2.2%), 2(0.7%), and 2(0.7%), respectively. Detection rates of Listeria spp. varied among four methods. The highest detection rate of Listeria spp. in market beef was found at USDA method and that of L. monocytogenes was found at Malthus method.

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Development and Validation of a Predictive Model for Listeria monocytogenes Scott A as a Function of Temperature, pH, and Commercial Mixture of Potassium Lactate and Sodium Diacetate

  • Abou-Zeid, Khaled A.;Oscar, Thomas P.;Schwarz, Jurgen G.;Hashem, Fawzy M.;Whiting, Richard C.;Yoon, Kisun
    • Journal of Microbiology and Biotechnology
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    • v.19 no.7
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    • pp.718-726
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    • 2009
  • The objective of this study was to develop and validate secondary models that can predict growth parameters of L. monocytogenes Scott A as a function of concentrations (0-3%) of a commercial potassium lactate (PL) and sodium diacetate (SDA) mixture, pH (5.5-7.0), and temperature (4-37DC). A total of 120 growth curves were fitted to the Baranyi primary model that directly estimates lag time (LT) and specific growth rate (SGR). The effects of the variables on L. monocytogenes Scott A growth kinetics were modeled by response surface analysis using quadratic and cubic polynomial models of the natural logarithm transformation of both LT and SGR. Model performance was evaluated with dependent data and independent data using the prediction bias ($B_f$) and accuracy factors ($A_f$) as well as the acceptable prediction zone method [percentage of relative errors (%RE)]. Comparison of predicted versus observed values of SGR indicated that the cubic model fits better than the quadratic model, particularly at 4 and $10^{\circ}C$. The $B_f$and $A_f$for independent SGR were 1.00 and 1.08 for the cubic model and 1.08 and 1.16 for the quadratic model, respectively. For cubic and quadratic models, the %REs for the independent SGR data were 92.6 and 85.7, respectively. Both quadratic and cubic polynomial models for SGR and LT provided acceptable predictions of L. monocytogenes Scott A growth in the matrix of conditions described in the present study. Model performance can be more accurately evaluated with $B_f$and $A_f$and % RE together.

A selective Assay To Measure Antioxidant Capacity in Both The Aqueous and Lipid Compartments of Plasma

  • Giancarlo Aldini;Yeum, Kyung-Jin;Robert. M. Russel;Norman I. Krinsky
    • Nutritional Sciences
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    • v.6 no.1
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    • pp.12-19
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    • 2003
  • The measurement of the total antioxidant capacity (TAC) of human plasma has been widely applied in nutritional science, for example to evaluate the antioxidant contribution of dietary components and to study, although indirectly, the bioavailability of dietary antioxidants. Several methods have been proposed for the measurement of TAC, most of them based on the ability of plasma to withstand the oxidative damage induced by aqueous radicals. Although plasma contains both hydrophilic and lipophilic antioxidants that interact through extensive cross-talk in most of the methods employed for the TAC measurement, the hydrophilic antioxidants such as ascorbic acid, uric acid, and protein thiols mainly contribute to the total antioxidant plasma capacity (almost 70%) while lipophilic antioxidants embedded in the lipoproteins (carotenoids, a-tocopherol, ubiquino1-10) participate only in a negligible amount (less than 5%). The present paper reviews the analytical methods used to assess the TAC and in particular focuses on new approaches that are capable of distinguishing the antioxidant capacity of both the aqueous and lipid compartments of plasma. The general principle of the method as well as some in vitro and ex vivo applications will be discussed within the text.

Machine Vision Technique for Rapid Measurement of Soybean Seed Vigor

  • Lee, Hoonsoo;Huy, Tran Quoc;Park, Eunsoo;Bae, Hyung-Jin;Baek, Insuck;Kim, Moon S.;Mo, Changyeun;Cho, Byoung-Kwan
    • Journal of Biosystems Engineering
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    • v.42 no.3
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    • pp.227-233
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    • 2017
  • Purpose: Morphological properties of soybean roots are important indicators of the vigor of the seed, which determines the survival rate of the seedlings grown. The current vigor test for soybean seeds is manual measurement with the human eye. This study describes an application of a machine vision technique for rapid measurement of soybean seed vigor to replace the time-consuming and labor-intensive conventional method. Methods: A CCD camera was used to obtain color images of seeds during germination. Image processing techniques were used to obtain root segmentation. The various morphological parameters, such as primary root length, total root length, total surface area, average diameter, and branching points of roots were calculated from a root skeleton image using a customized pixel-based image processing algorithm. Results: The measurement accuracy of the machine vision system ranged from 92.6% to 98.8%, with accuracies of 96.2% for primary root length and 96.4% for total root length, compared to manual measurement. The correlation coefficient for each measurement was 0.999 with a standard error of prediction of 1.16 mm for primary root length and 0.97 mm for total root length. Conclusions: The developed machine vision system showed good performance for the morphological measurement of soybean roots. This image analysis algorithm, combined with a simple color camera, can be used as an alternative to the conventional seed vigor test method.

Profiling of Recovery Efficiencies for Three Standard Protocols (FDA-BAM, ISO-11290, and Modified USDA) on Temperature-Injured Listeria monocytogenes

  • Lee, Hai Yen;Chai, Lay Ching;Pui, Chai Fung;Wong, Woan Chwen;Mustafa, Shuhaimi;Cheah, Yoke Kqueen;Issa, Zuraini Mat;Nishibuchi, Mitsuaki;Radu, Son
    • Journal of Microbiology and Biotechnology
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    • v.21 no.9
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    • pp.954-959
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    • 2011
  • There have been a number of studies conducted in order to compare the efficiencies of recovery rates, utilizing different protocols, for the isolation of L. monocytogenes. However, the severity of multiple cell injury has not been included in these studies. In the current study, L. monocytogenes ATCC 19112 was injured by exposure to extreme temperatures ($60^{\circ}C$ and $-20^{\circ}C$) for a one-step injury, and for a two-step injury the cells were transferred directly from a heat treatment to frozen state to induce a severe cell injury (up to 100% injury). The injured cells were then subjected to the US Food and Drug Administration (FDA), the ISO-11290, and the modified United States Department of Agriculture (mUSDA) protocols, and plated on TSAyeast (0.6% yeast), PALCAM agar, and CHROMAgar Listeria for 24 h or 48 h. The evaluation of the total recovery of injured cells was also calculated based on the costs involved in the preparation of media for each protocol. Results indicate that the mUSDA method is best able to aid the recovery of heat-injured, freeze-injured, and heat-freeze-injured cells and was shown to be the most cost effective for heat-freeze-injured cells.

Development of Kiln-Drying Schedules for Neolitsea sericea and Dendropanax morbifera Grown in Jeju Island (제주산 참식나무와 황칠나무의 건조스케줄 개발)

  • 김수원;정성호;정두진;박병수;강호양
    • Journal of the Korea Furniture Society
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    • v.14 no.2
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    • pp.13-20
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    • 2003
  • This research is to develop kiln-drying schedules for 2.7 mm thick boards of Neolitsea sericea and Dendropanax morbifera, which grow in the southern region of Korean Peninsula. These two species are lesser-known to woodcraft industry in this country. The proper USDA drying schedules for Neolitsea sericea and Dendropanax morbifera were found to be T10-C6 and T10-E6, respectively, by using the Quick Oven-drying Method. The boards dried in a kiln with the newly-developed schedules were revealed to be free from warping and checking.

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Soil Water Diffusivity and Soil Water Stress Coefficient Studies Using Weighting Lysimeter Data (토양수분확산계수 측정과 자동측정리이시메타를 이용한 토양수분계수 추정)

  • Oh, Dong-Shig;Ayars, James E.;Soppe, Richard;Eom, Ki-Cheol
    • Korean Journal of Soil Science and Fertilizer
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    • v.32 no.4
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    • pp.344-356
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    • 1999
  • A new and relatively simple equation for the soil water content-pressure head curve, ${\theta}$(h) is described in this paper. The particular form of the equation enables one to derive closed-form analytical expressions for the relative hydraulic conductivity, Kr, when substituted in the predictive conductivity models of Y. Mualem. Hopmans' equation is presented as an experimental method. The experienced method, $ET_a=K_sK_cET_o$ is introduced to estimate the actual evapotranspiration, $ET_a$(or $ET_c$). Using $ET_c$ and coil water data measured automatically in a weighing lusimeter, $K_s$ and $K_c$ values are estimated. Recently, FAO has introduced calculation procedures for the soil water(stress) coefficient, Ks in "Guidelines for computing crop water requirements".

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Discovery of Spathius ibarakius Belokobylskij et Maeto (Hymenoptera: Braconidae) as a Larval Ectoparasitoid of Citrus Longhorned Beetle in Korea (알락하늘소 유충의 외부기생 알락하늘소살이고치벌(Spathius ibarakius Belokobylskij et Maeto)의 발견)

  • Kim, Moo-Sung;Lee, Hye-Lin;Ku, Deok-Seo;Herard, Franck;Gould, Juli R.;Williams, David W.;Kim, Il-Kwon;Hong, Ki-Jeong
    • Korean journal of applied entomology
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    • v.55 no.3
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    • pp.285-291
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    • 2016
  • Spathius ibarakius Belokobylskij et Maeto, which belongs to the Spathius exarator species group (Hymenoptera: Braconidae: Doryctinae) was found as an ectoparasitoid of the first- and second-instar larvae of the citrus longhorned beetle, Anoplophora chinensis ($F{\ddot{o}}rster$) from Gwangneung, Pocheon, Korea. The discovery of this braconid wasp was made during the survey for parasitoids of the Asian and citrus longhorned beetles by using the sentinel log method. We herein describe diagnostic characters of S. ibarakius, including those of the male, and also provide illustrations. In addition, we present a host list of Korean species belong to genus Spathius.