Survival of Listeria monocytogenes during storage of ready-to-eat meat products processed by drying, fermentation, and/or smoking

The survival of Listeria monocytogenes was evaluated on 15 ready-to-eat meat products made using drying, fermentation, and/or smoking. The products were obtained from six processors and included summer sausage, smoked cured beef, beef jerky, snack stick, and pork rind and crackling products. The water activity of the products ranged from 0.27 (pork rinds and cracklings) to 0.98 (smoked cured beef slices). Products were inoculated with a five-strain cocktail of L. monocytogenes, repackaged under either vacuum or air, and then stored either at room temperature (21degrees C) or under refrigeration (5 degrees C) for 4 to 11 weeks. Numbers of L. monocytogenes fell for all products during storage, ranging from a decrease of 0.8 log CFU on smoked cured beef slices during 11 weeks under vacuum at 5 degrees C to a decrease of 3.3 log CFU on a pork rind product stored 5 weeks under air at 21degrees C. All of the products tested could be produced under alternative 2 of the U.S. Department of Agriculture regulations mandating control of L. monocytogenes on ready-to-eat meat and poultry products. For many of the products, 1 week of postprocessing storage prior to shipment would act as an effective postlethality treatment and would allow processors to operate under alternative I of these regulations.     

Conduction at domain walls in insulating Pb(Zr0.2 Ti0.8)O3 thin films

Domain wall conduction in insulating Pb(Zr(0.2) Ti(0.8))O(3) thin films is demonstrated. The observed electrical conduction currents can be clearly differentiated from displacement currents associated with ferroelectric polarization switching. The domain wall conduction, nonlinear and highly asymmetric due to the specific local probe measurement geometry, shows thermal activation at high temperatures, and high stability over time.     

Making News Necessary: How Journalism Resists Alternative Media's Challenge*

News coverage following Al Gore and George W. Bush's appearances on the Oprah Winfrey Show during the 2000 presidential campaign shows journalism asserting its authority to manage political discourse despite competition from alternative media. Analysis using Foucault's concepts of knowledge, power, and discipline reveals journalism affirming its continuing relevance and integrates insights from the framing and paradigm repair traditions. Journalists rejected Oprah as political discourse but reframed its elements to meet news criteria established by institutional journalism. Using negative stereotypes of women as political actors, journalists also disciplined Winfrey's “mostly female” audience for failing to adequately enact citizenship. Journalists thus both reasserted authority to manage political discourse and set standards for citizenship that positioned journalism as necessary to democracy.     

The Nine Lives of Buildings

Like cats being gifted with a new life every time they just miss their demise, buildings are constantly propelled towards change and reinvention in order to sustain their existence. Here Jill Stoner , Director of the Azrieli School of Architecture and Urbanism at Carleton University in Ottawa, and Professor of Architecture at the University of California, Berkeley, for 28 years, identifies and reflects upon nine possible future lives for buildings.     

Gold‐Cobalt Nanoparticle Alloys Exhibiting Tunable Compositions,Near‐Infrared Emission,and High T2 Relaxivity

We demonstrate the synthesis of discrete, composition‐tunable gold‐cobalt nanoparticle alloys (% Co = 0–100%; diameter = 2–3 nm), in contrast with bulk behavior, which shows immiscibility of Au and Co at room temperature across all composition space. These particles are characterized by transmission electron microscopy and ¹H NMR techniques, as well as inductively coupled plasma mass spectrometry, X‐ray photoelectron spectroscopy, and photoluminescence spectroscopy. In particular, ¹H NMR methods allow the simultaneous evaluation of composition‐tunable magnetic properties as well as molecular characterization of the colloid, including ligand environment and hydrodynamic diameter. These experiments also demonstrate a route to optimize bimodal imaging modalities, where we identify Au_xCo_yNP compositions that exhibit both bright NIR emission (2884 m ^?1cm^?1) as well as some of the highest per‐particle T ₂ relaxivities (12200 mm _NP ^?1s^?1) reported to date for this particle size range.     

The influence of non‐structural components on tall building stiffness

The lateral load resisting system of a multi‐storey building is considered to be an assembly of structural components, such as the structural frame, shear walls, concrete cores, etc. However, in reality, some so‐called ‘non‐structural components (NSCs)’ also play important roles in adding stiffness to the building. To evaluate the contributions from those NSCs and to quantify some of their contributions to the stiffness of the structure under service level loads, this paper reports on the analysis of a lateral load resisting system with different components so that the stiffness contribution from each individual component may be evaluated. Results from finite element analyses are verified by other theoretical calculations. Discussions and conclusions on the performance of both single components and the building system are also provided. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of frequency of feed delivery on the behavior and productivity of lactating dairy cows

The objective of this study was to determine the effect of feed delivery frequency on the behavioral patterns and productivity of lactating dairy cows. Twelve freestall-housed, lactating Holstein dairy cows, including 6 primiparous (PP) and 6 multiparous (MP), milked 3×/d (at 1400, 2200, and 0600h), were exposed to each of 3 treatments (over 21-d periods) in a replicated Latin square design. Treatments included feed delivery frequency of (1) 1×/d (at 1400 h), (2) 2×/d (at 1400 and 2200 h), and (3) 3×/d (at 1400, 2200, and 0600 h). Milk production as well as feeding, lying, and rumination behaviors were electronically monitored for each animal for the last 7 d of each treatment period. Milk samples were collected for the last 3 d of each period for milk component analysis. Dry matter intake (DMI) varied with feed delivery frequency, with greatest DMI observed in cows fed 3×/d (27.8 kg/d) compared with those fed 2×/d (27.0 kg/d) or 1×/d (27.4 kg/d). Treatment had no effect on milk yield (41.3 kg/d) or efficiency of production (1.54 kg of milk/kg of DMI). Cows that did not receive delivery of feed following the 2200 h milking (treatment 1) and 0600 h milking (treatments 1 and 2) had lower DMI during the first hour after milking than those that received feed at all milkings (treatment 3). Total feeding time and meal frequency, size, and duration did not vary by treatment, but PP cows consumed smaller meals at a slower rate, resulting in lower DMI compared with MP cows. Primiparous cows consumed 50.1% and 26.1% less dry matter than MP cows during the first meal following the first and second milkings, respectively. Lying time did not vary by treatment, but PP cows spent more time lying (10.3 vs. 8.3 h/d) than MP cows. Under 3×/d milking schedules, greater feed delivery frequency resulted in greater DMI as a function of increased DMI following the return from milking and the delivery of feed.     

Probabilistic approach to estimating indoor air concentrations of chlorinated volatile organic compounds from contaminated groundwater: a case study in San Antonio, Texas

This paper describes a probabilistic model, based on the Johnson-Ettinger algorithm, developed to characterize the current and historic exposure to tricholorethylene (TCE) and tetrachlorethylene (PCE) in indoor air from plumes of groundwater contamination emanating from the former Kelly Air Force Base in San Antonio, Texas. We estimate indoor air concentration, house by house, in 30?101 homes and compare the estimated concentrations with measured values in a small subset of homes. We also compare two versions of the Johnson-Ettinger model: one used by the Environmental Protection Agency (EPA) and another based on an alternative parametrization. The modeled mean predicted PCE concentration historically exceeded PCE screening levels (0.41 ug/m(3)) in 5.5% of houses, and the 95th percentile of the predicted concentration exceeded screening levels in 85.3% of houses. For TCE, the mean concentration exceeded the screening level (0.25 ug/m(3)) in 49% of homes, and the 95th percentile of the predicted concentration exceeded the screening level in 99% of homes. The EPA model predicts slightly lower indoor concentrations than the alternative parametrization. Comparison with measured samples suggests both models, with the inputs selected, underestimate indoor concentrations and that the 95th percentiles of the predicted concentrations are closer to measured concentrations than predicted mean values.     

Effect of prepartum administration of recombinant bovine somatotropin on health and performance of lactating dairy cows

A double-blind, randomized clinical trial was conducted in 5 commercial dairy herds in southern Ontario with 1,362 cows enrolled to evaluate the effect of prepartum administration of recombinant bovine somatotropin (rbST) on health and performance. Cows were randomly assigned to receive either 325 mg of sometribove zinc suspension (n = 680) or a placebo injection (n = 682; control) subcutaneously every 14 d until calving. Treatments started 28 to 22 d before expected calving, with a maximum of 3 treatments per cow. Serum samples taken at the time of enrollment, 1 wk before calving, and weekly for 3 wk after calving were analyzed for nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), glucose, aspartate aminotransferase, calcium, and haptoglobin. Diseases were recorded by farm staff. Incidences of clinical ketosis, clinical mastitis, displaced abomasum, metritis, retained placenta, milk fever, and lameness were similar between groups. Body condition score was lower for treated than for control cows at 3 wk after calving (3.13 and 3.17, respectively). Serum NEFA tended to be higher for treated than for control cows by 0.01 mmol/L. Overall BHBA was not different between groups, but BHBA for treated cows was higher in wk 1 after calving (750 and 698 μmol/L, respectively) and tended to be higher in wk 2 after calving (779 and 735 μmol/L, respectively). Incidence of hyperketonemia was similar between groups. Treated cows had higher serum glucose compared with control cows (2.8 and 2.7 mmol/L, respectively). We detected no differences in serum aspartate aminotransferase, calcium, or haptoglobin between groups. Milk yield was recorded daily for each cow for 63 d, and did not differ between groups (37.1 ± 0.5 kg and 36.7 ± 0.5 kg, respectively) but we detected a tendency for treated cows to produce 0.8 kg/d more milk than control cows in wk 1 after calving. We observed no difference between groups in the time from calving to first insemination or the probability of pregnancy at the first insemination. Groups did not differ in the proportion of anovular cows at 53 ± 3 d in milk based on serum progesterone measured from a subset of cows (38.0 and 34.3%, respectively, for treated and control groups). We found no difference between groups in dry matter intake from 21 d before calving to 63 d after calving in a subset of cows (17.4 ± 0.4 and 17.5 ± 0.4 kg/d, respectively). Based on results of the current study, biweekly (every 14 d) administration of rbST before calving to prevent disease and enhance performance is not recommended.