Agricultural Practices Influence Salmonella Contamination and Survival in Pre-harvest Tomato Production

Between 2000 and 2010 the Eastern Shore of Virginia was implicated in four Salmonella outbreaks associated with tomato. Therefore, a multi-year study (2012–2015) was performed to investigate presumptive factors associated with the contamination of Salmonella within tomato fields at Virginia Tech’s Eastern Shore Agricultural Research and Extension Center. Factors including irrigation water sources (pond and well), type of soil amendment: fresh poultry litter (PL), PL ash, and a conventional fertilizer (triple superphosphate – TSP), and production practices: staked with plastic mulch (SP), staked without plastic mulch (SW), and non-staked without plastic mulch (NW), were evaluated by split-plot or complete-block design. All field experiments relied on naturally occurring Salmonella contamination, except one follow up experiment (worst-case scenario) which examined the potential for contamination in tomato fruits when Salmonella was applied through drip irrigation. Samples were collected from pond and well water; PL, PL ash, and TSP; and the rhizosphere, leaves, and fruits of tomato plants. Salmonella was quantified using a most probable number method and contamination ratios were calculated for each treatment. Salmonella serovar was determined by molecular serotyping. Salmonella populations varied significantly by year; however, similar trends were evident each year. Findings showed use of untreated pond water and raw PL amendment increased the likelihood of Salmonella detection in tomato plots. Salmonella Newport and Typhimurium were the most frequently detected serovars in pond water and PL amendment samples, respectively. Interestingly, while these factors increased the likelihood of Salmonella detection in tomato plots (rhizosphere and leaves), all tomato fruits sampled (n = 4800) from these plots were Salmonella negative. Contamination of tomato fruits was extremely low (< 1%) even when tomato plots were artificially inoculated with an attenuated Salmonella Newport strain (104 CFU/mL). Furthermore, Salmonella was not detected in tomato plots irrigated using well water and amended with PL ash or TSP. Production practices also influenced the likelihood of Salmonella detection in tomato plots. Salmonella detection was higher in tomato leaf samples for NW plots, compared to SP and SW plots. This study provides evidence that attention to agricultural inputs and production practices may help reduce the likelihood of Salmonella contamination in tomato fields

Persistent Problems and Emerging Issues in English Education in Korea

Although it is generally agreed that English education in Korea has improved greatly since its beginning in 1983, there are still many important areas that have persistent problems ， and the profession of English teaching is faced with some emerging issues. English education has progressed both quantitatively and qualitatively, since English became a required school subject in elementary school in 1997. The teachers and students general English proficiency have also improved. However, there are still many teachers whose English ability leaves much to be desired. Also, students losing confidence and interest in English is another persistent problem. The societys change also poses challenges to the English teaching profession. This paper discusses these improvements and persistent problems and emerging issues in English education in Kore

미국의 한 이중언어 몰입프로그램 참여 미국 어린이들의 한국어 중간언어 오류

This study attempts to dεscribe the interlanguage errors in the Korean writings by English-speaking American children enrolled in a Korean/English two-way immersion program in the US. The study employs a longitudinal approach and identifies the types of errors the students make over the period of three years. The study found that the students' errors demonstrate both interlingual and intralingual transfers. ηle kindergarten level students made basic orthographic errors in their writing, while first graders made spelling errors and basic grammatical errors. Sociolinguistic errors were observed from first gradε on. Implications for second language teaching and suggestions for further research are discussed

Changes in the Status of the Second Foreign Language Education in Korea

Foreign language education in Korea has a long history. Since the introduction of Chinese characters in the 2nd century, many foreign languages have been taught in Korea. European languages were introduced in the late part of the 19th century, but the teaching of them experienced a setback during the Japanese colonial period. After liberation in 1945, English became the most important foreign language, while other foreign languages were called second foreign languages. German and French were the two most popular second foreign languages in the early years after liberation, but Japanese increased its weight as German and French gradually lost their appeal to high school students. Chinese is also steadily gaining in popularity. A corollary of this change was the governments retraining program to convert German and French language teachers to Japanese or Chinese language teachers. The present paper discusses these and other changes in the status of second foreign languages, and recommends that the government take some drastic measures to revive the balanced development of second foreign-language education

Firming non-political actors to enhance the quality of urban service delivery. A review on the City Development Forums in Uganda

Purpose: This study aimed to explore the dependability of non-political forums specifically considering the City Development Forums in Uganda. This investigation was motivated by the idea of City Development Forums being a known spectrum for Non-Political Forums to play a role in affairs otherwise affecting a City or Municipality. Research methodology: A Desk review method was adopted in which data was collected from obtainable resources specifically Publications, the Internet, Official Reports, etc., followed by cross-referencing and collation of data. Results: The outcomes reveal that a set of six principles inform City Development Forums, viz. shared accountability of every stakeholder in ensuring sustainable development; integrated planning framework for sustainable urban development; effective coordination among every urban stakeholder; local teamwork and networking; bottom-up broad-based stakeholder participatory consultations; and mobilization of resources for sustainable urban development. Limitations: This study adopted a review of secondary data yet if primary data were to be used, maybe, the results would have been different. Therefore, a different study can be conducted using primary data to determine whether these results hold sway and, if any, the justifications for the noticeable variances. Contribution: This study contributes to the understanding of local community development initiatives using the empowerment approach

Inactivation of Escherichia coli O157:H7 on Romaine Lettuce When Inoculated in a Fecal Slurry Matrix

A field trial was conducted in July 2011 to quantify the inactivation rate of Escherichia coli O157:H7 when mixed with fecal slurry and applied to romaine lettuce leaves. Lettuce was grown under commercial conditions in Salinas Valley, CA. One-half milliliter of rabbit fecal slurry, containing 6.3 × 107 CFU of E. coli O157:H7, was inoculated onto the upper (adaxial) surface of a lower leaf on 240 heads of lettuce within 30 min after a 2.5-h irrigation event. Forty-eight romaine lettuce heads were collected per event at 2.5 h (day 0.1), 19.75 h (day 0.8), 43.25 h (day 1.8), 67.25 h (day 2.8), and 91.75 h (day 3.8) postinoculation and were analyzed for the concentration of E. coli O157:H7 (Ct). E. coli O157:H7 was detected on 100% of collected heads in concentrations ranging from 340 to 3.40 × 1010 most probable number (MPN) per head. Enumeration data indicate substantial growth of E. coli O157:H7 postinoculation (2.5 h), leading to elevated concentrations, 1 to 3 log above the starting inoculum concentration (Co). By the end of the 92-h trial, we observed a net 0.8-log mean reduction of E. coli O157:H7 compared with Co; however, after accounting for the substantial bacterial growth, there was an overall 2.3-log reduction by the final sampling event (92 h). On the basis of two different regression models that used either the raw data for Ct or log-transformed values of Ct/Co during the period 2.5 to 91.75 h postinoculation, there was an estimated 76 to 80% reduction per day in bacterial counts; however, more accurate predictions of MPN per head of lettuce were generated by using non-log-transformed values of Ct. This study provides insight into the survival of E. coli O157:H7 transferred via splash from a contaminated fecal source onto produce during irrigation. Moreover, these findings can help generate inactivation times following a potential contamination incident

A surface definition code for turbine blade surfaces

A numerical interpolation scheme has been developed for generating the three-dimensional geometry of wind turbine blades. The numerical scheme consists of (1) creating the frame of the blade through the input of two or more airfoils at some specific spanwise stations and then scaling and twisting them according to the prescribed distributions of chord, thickness, and twist along the span of the blade; (2) transforming the physical coordinates of the blade frame into a computational domain that complies with the interpolation requirements; and finally (3) applying the bi-tension spline interpolation method, in the computational domain, to determine the coordinates of any point on the blade surface. Detailed descriptions of the overall approach to and philosophy of the code development are given along with the operation of the code. To show the usefulness of the bi-tension spline interpolation code developed, two examples are given, namely CARTER and MICON blade surface generation. Numerical results are presented in both graphic data forms. The solutions obtained in this work show that the computer code developed can be a powerful tool for generating the surface coordinates for any three-dimensional blade

Transfer of Escherichia coliO157:H7 from Simulated Wildlife Scat onto Romaine Lettuce during Foliar Irrigation

A field trial in Salinas Valley, California, was conducted during July 2011 to quantify the microbial load that transfers from wildlife feces onto nearby lettuce during foliar irrigation. Romaine lettuce was grown using standard commercial practices and irrigated using an impact sprinkler design. Five grams of rabbit feces was spiked with 1.29 × 10(8) CFU of Escherichia coli O157:H7 and placed - 3, - 2, and - 1 days and immediately before a 2-h irrigation event. Immediately after irrigation, 168 heads of lettuce ranging from ca. 23 to 69 cm (from 9 to 27 in.) from the fecal deposits were collected, and the concentration of E. coli O157:H7 was determined. Thirty-eight percent of the collected lettuce heads had detectable E. coli O157:H7, ranging from 1 MPN to 2.30 × 10(5) MPN per head and a mean concentration of 7.37 × 10(3) MPN per head. Based on this weighted arithmetic mean concentration of 7.37 × 10(3) MPN of bacteria per positive head, only 0.00573% of the original 5 g of scat with its mean load of 1.29 × 10(8) CFU was transferred to the positive heads of lettuce. Bacterial contamination was limited to the outer leaves of lettuce. In addition, factors associated with the transfer of E. coli O157:H7 from scat to lettuce were distance between the scat and lettuce, age of scat before irrigation, and mean distance between scat and the irrigation sprinkler heads. This study quantified the transfer coefficient between scat and adjacent heads of lettuce as a function of irrigation. The data can be used to populate a quantitative produce risk assessment model for E. coli O157:H7 in romaine lettuce to inform risk management and food safety policies