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Korea Food Research Institute, Gyeonggi 463-746, KoreaAbstractThe possibility of DNA comet assay as a rapid method for screening the irradiated vegetables and grains was evaluated. Vegetables (spring onion, garlic, and tomato) irradiated at 0～3 kGy and grains (rice flour and black soybean) irradiated at 0～9 kGy were used as samples. Optimum DNA comet assay conditions, such as elution, sedimentation of suspension, and lysis time of cell, were established. The optimum conditions for vegetables were 10 min for the elution time, 0 min for the sedimentation time, and 5 min for the lysis time. The optimum conditions for grains were 15 min for the elution time, 60 min for the sedimentation time, and 30 min for the lysis time. For the food application of DNA comet assay, it was possible to screen various food samples irradiated at the following doses: spring onion at 2 kGy, garlic at 3 kGy, tomato at 1 kGy, rice flour at 9 kGy, and black soybean at 3 kGy. Each sample showed different forms and sizes in DNA comet. Therefore, further studies on various methods using comet shape, concentration, or area in DNA comet assay are necessary.Key words: DNA comet assay, irradiation, single cell gel electrophoresis, screen

Biofilm-forming characteristics of 72 different Enterobacter sakazakii strains on plastic surface were tested. And the influence of the artificial growth medium and infant milk formula (IMF) was also determined. Quantification of biofilm formation was performed with medium including brain heart infusion broth, nutrient broth, tryptic soy broth, 1/20 diluted tryptic soy broth (1/20-TSB) and differently diluted IMF on plastic microtiter plates. According to the result, reconstituted IMF was the more effective medium for biofilm formation than artificial medium. At normal IMF concentration, 56 strains produced biofilm (77.8%) but most suitable artificial medium and 1/20-TSB; 12 strains produced biofilm (16.7%). These results indicated that the IMF offers more opportunities of biofilm formation on plastic surface. Therefore, all bottles and equipment should be effectively cleaned for preventing biofilm formation by IMF and E. sakazakii. PRACTICAL APPLICATIONS E. sakazakii could produce biofilm and protect the cells from being affected by disinfectants. It is also more difficult to wash such bacteria off from the surface they attached with biofilm and the chance of cross-contamination could increase. The ability of biofilm formation could be influenced by different strains and also the growing media. By this study, we observed that IMF is the most effective media for biofilm formation among all the other media tested. Since IMF is the most important vehicle and source of E. sakazakii, it is important to surely clean and disinfect all the processing facilities in the factory and all the utensils, bottles, or teats used for IMF preparation. As biofilm would be formed when contact time increased, it is recommended not to sit the feeding bottles with IMF for a prolonged time to prevent biofilm formation and therefore minimize the opportunity of E. sakazakii infection.

Stearidonic acid (SDA), an n-3 polyunsaturated fatty acid (PUFA), can be obtained from plant origin oils and it can be a good source of PUFA for vegetarians. SDA can be easily converted to longer PUFA such as docosahexaenoic acid and eicosapentaenoic acid. Highly purified stearidonic acid (SDA) was prepared successfully from echium oil via an enzymatic method combined with preparative high performance liquid chromatography. In the 1(st) step, SDA enrichment was accomplished using Candida rugosa lipase and 39.5% of SDA was obtained in the fatty acid fraction. Subsequently, the 1(st) reaction mixture was used for the 2(nd) enzymatic esterification without any separation process. The 2(nd) esterification was conducted for further SDA enrichment in a packed-bed reactor using Lipozyme RM IM from Rhizomucor miehei and the SDA content increased in a very short residence time. Ethanol was selected as an appropriate alcohol to react as an acyl receptor, and the other conditions for SDA enrichment were optimized at 20°C of temperature, and 1:4 of molar ratio (i.e., fatty acid to ethanol). Under these conditions, 51.6% of SDA was obtained in the fatty acid fraction after a residence time of 15 min. Finally, highly purified SDA (purity, >99%) was obtained by prep-HPLC using the SDA-rich fraction obtained from the two-step lipase-catalyzed esterification.

Enterobacter sakazakii is a member of the Enterobacteriaceae and has physiological characteristics similar to those of Escherichia coli O157:H7 (negative D-sorbitol fermentation, positive glucose and lactose fermentation, and negative H2S production). The purpose of this study was to evaluate the efficiency of enrichment broths recommended for E. sakazakii enrichment. Growth and recovery ratio of E. sakazakii were compared in media including modified tryptone soya broth supplemented with novobiocin (mTSB + N), modified Escherichia coli broth with novobiocin (mEC + N), Enterobacteriaceae enrichment (EE) broth, buffered peptone water supplemented with vancomycin, cefixime and cefsulodin (BPW + VCC), and rehydrated infant milk formula (IMF) with or without antibiotics. The EE broth that was recommended by the FDA showed the most effective enrichment for growth of E. sakazakii, followed by rehydrated IMF. Other media such as mTSB + N, mEC + N and BPW + VCC did not support growth of E. sakazakii compared to EE and rehydrated IMF. They were not considered suitable for the enrichment of E. sakazakii. When evaluated for recovery of E. sakazakii among other Enterobacteriaceae, strains of E. sakazakii were all recovered in EE broth after 6 and 18 h; thus, the EE broth was considered the most effective enrichment broth in this study. Rehydrated IMF also showed higher recovery ratios (3/4, 4/4) after 6 and 18 h than the other recommended enrichment broths.

A new method was developed to rapidly monitor the Enterobacter sakazakii viable counts in reconstituted infant milk formula. Ninety six–well microtiter plates were used to perform a miniaturized 10-tube most-probable-number (MPN) enumeration protocol for E. sakazakii. This procedure is based on fluorogenic detection as a result of the growth and α-glucosidase production from E. sakazakii in broth containing 4-methylumbelliferyl-α-D-glucoside (OK medium). The correlation between E. sakazakii counts by conventional plating and microtiter MPN methods was highly agreeable in 0.2% peptone water (R2 = 0.94) and reconstituted infant milk formula (R2 = 0.91). From these results, the new rapid method can quickly monitor E. sakazakii counts in infant milk formula with a high correlation with the conventional plating method. The results indicate that the microtiter MPN method required much shorter incubation times (

Drive-by-Wire (DBW) technologies improve conventional vehicle performance and a Steer-by-Wire (SBW) system is one of the DBW technologies. The control algorithm of the SBW system was designed in this paper. To verify the control algorithm, the SBW system is modeled using the bond graph method. The first aim of the control algorithm is controlling the steering wheel assist motor to make the real vehicle's steering feel and for a vehicle designer to adjust the steering feel as he finds necessary. Therefore, torque map is designed to determine the steering wheel reactive torque. The second aim is controlling the front wheel assist motor to improve vehicle's maneuverability and stability by using understeer and oversteer propensity of a vehicle. Furthermore, high performance control algorithm is proposed in this paper and Active Roll Stability Control (ARSC) method is designed as one of the high performance control algorithm.

The chemical composition and oxidative stability of safflower oil prepared from the seed roasted, at different roasting temperatures (140–180 °C), were evaluated and compared with those of unroasted safflower oil. The colour development and phosphorus content of oils increased significantly as roasting temperature increased. The fatty acid compositions of safflower oils did not change with roasting temperature. The major fatty acid was linoleic acid (ca. 80%). Four phospholipid classes, namely, PE, PI, PA and PC, were identified. The major phospholipid component of safflower seed oil is PI. However, the proportion of PI in the safflower oil increased significantly as roasting temperature increased (P

The ability of tricyclic antidepressants (TCAs) to inhibit phenytoin p-hydroxylation was evaluated in vitro by incubation studies of human liver microsomes and cDNA-expressed cytochrome p450s (p450s). The TCAs tested were amitriptyline, imipramine, nortriptyline, and desipramine. Amitriptyline and imipramine strongly and competitively inhibited phenytoin p-hydroxylation in microsomal incubations (estimated K(i) values of 5.2 and 15.5 micro M, respectively). In contrast, nortriptyline and desipramine produced only weak inhibition. In the incubation study using cDNA-expressed P450s, both CYP2C9 and CYP2C19 catalyzed phenytoin p-hydroxylation, whereas TCAs inhibited only the CYP2C19 pathway. All of the TCAs tested inhibited CYP2D6-catalyzed dextromethorphan-O-demethylation competitively, with estimated K(i) values of 31.0, 28.6, 7.9, and 12.5 micro M, respectively. The tertiary amine TCAs, amitriptyline and imipramine, also inhibited CYP2C19-catalyzed S-mephenytoin 4'-hydroxylation (estimated K(i) of 37.7 and 56.8 micro M, respectively). The secondary amine TCAs, nortriptyline and desipramine, however, showed minimal inhibition of CYP2C19 (estimated IC(50) of 600 and 685 micro M, respectively). None of the TCAs tested produced remarkable inhibition of any other p450 isoforms. These results suggest that TCAs inhibit both CYP2D6 and CYP2C19 and that the interaction between TCAs and phenytoin involves inhibition of CYP2C19-catalyzed phenytoin p-hydroxylation.

This study was conducted to investigate the effects of aerosolized malic acid and ultraviolet light (UV-C) for inhibiting the growth of foodborne pathogens, Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes, on fresh-cut lettuce. The antimicrobial effects of aerosolized 2% malic acid and UV-C, alone or in combination, were tested. Ten grams of lettuce were inoculated with three strains of each pathogens and treated with aerosolized malic acid for 20 min and UV-C for 30 min. After each treatment, lettuce was stored at 5 °C for 15 days. Sequential treatment (aerosolized malic acid after UV-C) was the most effective for reducing E. coli O157:H7, S. Typhimurium, and L. monocytogenes and resulted in reduction of 2.89, 1.38, and 2.95 log10 CFU/g after treatment and 3.15, 3.00, and 4.58 log10 CFU/g after 15 days, respectively. These results suggested that combined treatment with aerosolized malic acid after UV-C can be a useful intervention method for improving the microbial safety of fresh-cut produce. Practical applications The experiment suggested new method on the inactivation of foodborne pathogens on lettuce. Treatment with aerosolized 2% malic acid after UV-C was the most effective method to inhibit the growth of foodborne pathogens in this study. This method will be helpful for fresh-cut lettuce producers to manage the safety and quality of lettuce.

Clostridium difficile exists within the intestines of animals and in meat products. Enrichment of C. difficile in an appropriate medium is necessary for the detection of C. difficile in meat products. Non-selective media (brain heart infusion medium [TBHI] and cooked meat medium containing sodium taurocholate [TCM]) and selective media (cycloserine-cefoxitin-fructose medium [TCCFB] and C. difficile moxalactam-norfloxacin medium containing antibiotics and sodium taurocholate [TCDMN]) can be used to enrich C. difficile. This study aimed to evaluate non-selective and selective enrichment media for the recovery of C. difficile from beef specimens. The efficiency of the enrichment media was investigated on the basis of the recovery frequency of C. difficile from beef specimens inoculated with C. difficile. The beef specimens were inherently contaminated with bacteria (around 10(4)CFUg(-1)), and further inoculated with C. difficile (around 10(0)CFUg(-1)). The antibiotics in TCCFB and TCDMN adversely affected C. difficile growth. The bacteria inherent to these specimens exhibited resistance to antibiotics and grew during the enrichment of C. difficile-inoculated chopped beef in TCCFB and TCDMN, which hindered the recovery of C. difficile. The frequency of recovery of C. difficile from beef specimens in TCM was higher than that from any other enrichment medium.

The impedimetric characteristics of an immunosensor depend on the electrical properties of an immunosensor substrate. The impedimetric characteristics of an immunosensor compared with adsorption of Listeria monocytogenes were investigated on an aluminum surface insulated with an electrically resistive aluminum oxide layer. Antibody for L. monocytogenes (anti-L. monocytogenes) was immobilized on an aluminum surface that was insulated with a native air-formed aluminum oxide layer. The resistance of impedance (R) value of an aluminum-based immunosensor decreased, especially at 10(4) to 10(6) Hz, where the effect of the reactance of impedance (X) was minimal when L. monocytogenes was adsorbed on the immunosensor surface. The R value of the immunosensor at 81 kHz decreased proportionally to the concentration of L. monocytogenes from 1.3 to 4.3 log CFU mL(-1) . The adsorption of L. monocytogenes produced local protrusions on the immunosensor surface, causing physicochemical changes in the ionic layer formed on the immunosensor surface by a sinusoidal electrical signal input, which might help electrical current to flow and cause the R value to decrease.

We apply a glass reflow process to fabricate tiny glass nozzles with inner diameter of 20 microns and with a height of 150 microns which is impossible to achieve with a conventional etching process. Due to the enhanced aspect ratio of the nozzle, we observe better printing performances such as narrow line width below 10 microns and anti-wetting of ink around a nozzle. High frequency drop jetting up to 10 kHz is observed by applying high voltage pulse signals on ink inside the nozzle. Silver particle ink is also printed well and continuous line patterns are fabricated.

Particular aspects provide novel compositions and methods useful for the growth, isolation and detection of microorganisms that have α-glucosidase activity (e.g., the bacterium E. sakazakii ). Certain embodiments provide a novel growth and/or plating media, comprising a fluorogenic α-glucosidase substrate, which is both selective for and differential to E. sakazakii . In particular embodiments, the α-glucosidase substrate comprises 4-methylumbelliferyl-α-D-glucoside. Additional embodiments relate to a selection media. Further embodiments relate to a selective medium that is based on Tryptone Bile agar. Still further embodiments relate to OK media as defined herein. Other embodiments of the invention relate to methods for growing bacterial cultures on media that is selective for and differential to microorganisms that have α-glucosidase activity (e.g., the bacterium E. sakazakii ).

Minimum time and detection limit required to detect Escherchia coli O157:H7 in fresh-cut cabbage examined by real-time polymerase chain reaction (PCR). The detection limit of E. coli O157:H7 in modified E. coli (mEC) broth by real-time PCR was 1.53 log CFU mL-1. A growth curve was produced by counting the cell number of E. coli O157:H7 in mEC broth during cultivation at 37°C. The growth curve was well fitted by the equation, y=0.0148x2+0.4244x+1.0472 (R2=0.9945), where y is the cell growth concentration (log CFU mL-1) and x is time (h). Assuming that E. coli O157:H7 is present in produce at low concentrations (1 cell in 25 g sample), detection by real-time PCR would be possible only when the cell number increased over the detection limit. The growth curve indicated that culture in mEC broth required at least 6 h and 20 min of enrichment to exceed the detection limit; therefore, the total time required for detection time was less than nine hours, which included the DNA isolation time (30 min) and the real-time PCR operating time (2 h). This method could be used for presumptive screening of E. coli O157:H7 in fresh-cut produce, which demands a rapid detection time for safety management.

Aerosolized sanitizer was investigated as a potential alternative to aqueous and gaseous sanitizers for produce. Peroxyacetic acid was aerosolized (5.42 to 11.42 microm particle diameter) by a commercially available nebulizer into a model cabinet. Iceberg lettuce leaves were inoculated with three strains each of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium and then treated with aerosolized peroxyacetic acid for 10, 30, or 60 min in a model aerosol cabinet at room temperature (22 +/- 2 degrees C). After treatment, surviving healthy and injured bacterial cells were enumerated on appropriate selective agars or using the overlay agar method. Inoculated iceberg lettuce leaves exposed to aerosolized peroxyacetic acid for 10 min exhibited a 0.8-log reduction in E. coli O157:H7, a 0.3-log reduction in Salmonella Typhimurium, and a 2.5-log reduction in L. monocytogenes when compared with the control. After 30 min of treatment, the three pathogens were reduced by 2.2, 3.3, and 2.7 log, and after 60 min, the reductions were 3.4, 4.5, and 3.8 log, respectively. Aerosolization may be a new and convenient method for sanitizing produce for storage or shipping.

Rhus verniciflua Stokes (RVS), one of traditional medicinal plants in Asia, was found to have pharmacological activities such as antioxidative and antiapoptotic effects, raising the possibility for the development of a novel class of anti-cancer drugs. Thus, potential genotoxic effects of RVS in three short-term mutagenicity assays were investigated, which included the Ames assay, in vitro Chromosomal aberration test, and the in vivo Micronucleus assay. In Ames test, the addition of RVS water extracts at doses from 313 up to 5000 mg/plate induced an increase more than 2-fold over vehicle control in the number of revertant colonies in TA98 and TA1537 strains for detecting the frame-shift mutagens. The similar increase in reversion frequency was observed after the addition of RVS ethanol extracts. To assess clastogenic effect, in vitro chromosomal aberration test and in vivo micronucleus assay were performed using Chinese hamster lung cells and male ICR mice, respectively. Both water and ethanol extracts from RVS induced significant increases in the number of metaphases with structural aberrations mostly at concentrations showing the cell survival less than 60% as assessed by in vitro CA test. Also, there was a weak but statistically significant increase in number of micronucleated polychromatic erythrocytes (MNPCEs) in mice treated with water extract at 2000 mg/kg while ethanol extracts of RVS at doses of up to 2000 mg/kg did not induce any statistically significant changes in the incidence of MNPCEs. Therefore, our results lead to conclusion that RVS acts as a genotoxic material based on the available in vitro and in vivo results.

This study was conducted to investigate the effect of steam treatment on the reduction of Salmonella enterica serovar Enteritidis on the surface of raw almonds. Two cultivars, 'Nonpareil' and 'Mission', were studied. Salmonella Enteritidis was inoculated on the surface of raw almonds, which were then treated with steam (93 degrees C +/- 1 degrees C) for 5, 15, 25, 35, 45, 55, and 65 s. After steam treatment, samples were plated on xylose lysine desoxycholate (XLD) and overlay (OV) XLD as a selective and nonselective agar for Salmonella, respectively, to investigate the extent of sublethal injury in Salmonella. Steam treatment of raw almonds effectively reduced Salmonella Enteritidis, and the effect was pronounced with increasing treatment time. After 65 s of steam treatment, reductions in Salmonella Enteritidis populations were 5.7 log and 5.8 log for 'Nonpareil' and 4.0 log and 4.1 log for 'Mission' when enumerated on XLD and OV XLD, respectively. There was no significant difference in population estimates determined with XLD and OV XLD over time (P > 0.05). The effect of the steam treatment was significantly different between two almond cultivars. Salmonella inoculated onto 'Mission' was more resistant to the steam treatment than that on 'Nonpareil', indicating that varietal differences must be considered in the application of steam for the disinfection of raw almonds. The present investigation revealed the potential usefulness of steam treatments for the control of pathogens in raw almonds.

Work information in a construction project can be effectively used to analyze the project status related to schedule, cost, productivity etc. The purpose of this research is to develop a computer-based system using PDA and barcode technology to measure and monitor the amount of workforce resources and productivity. The developed system is expected to effectively assist schedule planning and management for present and prospective construction projects.