Reduction of Listeria monocytogenes on frankfurters treated with lactic acid solutions of various temperatures

United States regulations require ready-to-eat meat and poultry processors to control Listeria monocytogenes using interventions which may include antimicrobials that reduce post-processing contamination by at least 1 log-cycle; if the treatment achieves ≥2 log reductions, the plant is subject to less frequent microbial testing. Lactic acid (LA) may be useful as a post-lethality intervention and its antimicrobial properties may increase with temperature of application. The aim of this study was to evaluate the effect of LA solution concentration and temperature on L. monocytogenes counts of inoculated frankfurters and to identify parameters (concentration, temperature, and time) that achieve 1 and 2 log-unit immediate reductions. Frankfurters were surface-inoculated with a 10-strain mixture of L. monocytogenes (4.4 ± 0.1 log CFU/cm²) and then immersed in distilled water or LA solutions (0–3%) of 4, 25, 40, or 55 °C for 0–120 s. A regression equation for L. monocytogenes reduction included significant (P < 0.05) effects by the terms of concentration, time, temperature, and the interaction of concentration and temperature; other tested parameters (other interactions, quadratic and cubic terms), within the experimental range examined, did not affect (P ≥ 0.05) the extent of reduction. Results indicated that the effectiveness of LA against L. monocytogenes, in addition to concentration, increased with solution temperature (in the range of 0.6–2.8 log CFU/cm²). The developed equation may allow processors to vary conditions of treatment with LA to achieve a 1 or 2 log-unit reduction of the pathogen and comply with United States regulations.     

Post-processing application of chemical solutions for control of Listeria monocytogenes, cultured under different conditions, on commercial smoked sausage formulated with and without potassium lactate-sodium diacetate

This study evaluated post-processing chemical solutions for their antilisterial effects on commercial smoked sausage formulated with or without 1.5% potassium lactate plus 0.05% sodium diacetate, and contaminated (approximately 3-4 log cfu/cm(2)) with 10-strain composite Listeria monocytogenes inocula prepared under various conditions. Inoculated samples were left untreated, or were immersed (2 min, 25 +/- 2 degrees C) in solutions of acetic acid (2.5%), lactic acid (2.5%), potassium benzoate (5%) or Nisaplin (0.5%, equivalent to 5000 IU/ml of nisin) alone, and in sequence (Nisaplin followed by acetic acid, lactic acid or potassium benzoate), before vacuum packaging and storage at 10 degrees C (48 days). Acetic acid, lactic acid or potassium benzoate applied alone reduced initial L. monocytogenes populations by 0.4-1.5 log cfu/cm(2), while treatments including Nisaplin caused reductions of 2.1-3.3 log cfu/cm(2). L. monocytogenes on untreated sausage formulated with antimicrobials had a lag phase duration of 10.2 days and maximum specific growth rate (mu(max)) of 0.089 per day, compared to no lag phase and mu(max) of 0.300 per day for L. monocytogenes on untreated product that did not contain antimicrobials in the formulation. The immersion treatments inhibited growth of the pathogen for 4.9-14.8 days on sausage formulated without potassium lactate-sodium diacetate; however, in all cases significant (P < 0.05) growth occurred by the end of storage. The antilisterial activity of chemical solutions was greatly enhanced when applied to product formulated with antimicrobials; growth was completely inhibited on sausage treated with acetic or lactic acid alone, and in sequence with Nisaplin. In general, habituation (15 degrees C, 7 days) of L. monocytogenes cells, planktonically or as attached cells to stainless-steel coupons in sausage homogenate prior to contamination of product, resulted in shorter lag phase durations compared with cells cultivated planktonically in a broth medium. Furthermore, when present, high levels of spoilage flora were found to suppress growth of the pathogen. Findings of this study could be useful to US meat processors in their efforts to select required regulatory alternatives for control of post-processing contamination in meat products.     

Targeted,Needle‐Free Vaccinations in Skin using Multilayered,Densely‐Packed Dissolving Microprojection Arrays

Targeting of vaccines to abundant immune cell populations within our outer thin skin layers using miniaturized devices—much thinner than a needle and syringe, could improve the efficacy of vaccines (and other immunotherapies). To meet this goal, a densely packed dissolving microprojection array (dissolving Nanopatch) is designed, achieving functional miniaturization by 1) formulating small microneedles (two orders of magnitude smaller than a standard needle and syringe) and 2) multiple layering of the payload within microprojections with tight tolerances (of the order of a micrometer). The formulation method is suitable to many vaccines because it is without harsh or complex chemical processes, and it is performed at low temperatures and at a neutral pH. When the formulated dNPs are applied to skin, consistent and robust penetration is achieved, rapidly targeting the skin strata of interest (<5 min; significantly faster than larger dissolving microneedles that have been previously reported). Resultant diffusion is significantly enhanced within the dermis compared with the epidermis. Using two different antigens (ovalbumin and a commercial trivalent influenza vaccine [Fluvax2008]), the administration of these dissolving patches generate robust systemic immune responses in a mouse model. To the authors' knowledge, this is the first report of successful vaccination with any form of dissolving microneedles. The patches made by this method therefore have the potential for pain‐free, needle‐free, and effective vaccination in humans.     

A New Era of Minimal Effects? A Response to Bennett and Iyengar

This article takes up Bennett and Iyengar's (2008) call for debate about the future of political communication effects research. We outline 4 key criticisms. First, Bennett and Iyengar are too quick to dismiss the importance of attitude reinforcement, long recognized as an important type of political media influence. Second, the authors take too narrow a view of the sources of political information, remaining fixated on news. Third, they offer an incomplete portrayal of selective exposure, exaggerating the extent to which individuals avoid attitude-discrepant information. Finally, they lean toward determinism when describing the role technologies play in shaping our political environment. In addition, we challenge Bennett and Iyengar's assertion that only brand new theory can serve to help researchers understand today's political communication landscape. We argue that existing tools, notably the Elaboration Likelihood Model (ELM), retain much utility for examining political media effects. Contrary to Bennett and Iyengar's claims, the ELM suggests that the contemporary political information environment does not necessarily lead to minimal effects.     

Economical emergency response and lower profile states: A behavioral health reference for the rest of us.

In some jurisdictions, major disasters rarely occur. Those responsible for providing behavioral health services in these jurisdictions have less opportunity to accrue experience and understanding of disaster and less access to behavioral health funding support and guidance than is true elsewhere. This affects both preparedness and response. The state of Oregon, a lower profile state in terms of disaster experience, participated in the national TOPOFF 4 dirty bomb exercise. With necessity serving as the mother of invention, circumstances converged to reveal alternative strategies that may serve some lower profile jurisdictions more effectively than recommended standard practice and that appear to have economical benefit. Response strategy relied on recruitment and assignment of sufficient responders by collaborating among multiple existing trained resources rather than using a state or local public health volunteer registry. It also implemented just-in-time trainings and took advantage of other spontaneous teaching opportunities rather than relying on the efficacy of more costly traditional training models. Potential strategies for more economical preparedness and response activity and recommendations for addressing some current national shortcomings are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ceramic fuel cells to replace metal burners

Global warming is thought to result from emissions largely caused by combustion reactions. Designs of burners and specifications of their materials are therefore of primary importance in restraining the warming phenomena. This paper proposes a new type of ceramic burner which incorporates many of the innovations which are needed to improve burner performance, including catalytic combustion, premixed fuel/air, recuperation of combustion heat, recycling of reaction products, electric-ignition and electron extraction. The key problems of fuel variation and thermal shock resistance of the ceramic are addressed through the concept of 'reaction gradient' in which the rich sequence of oxidation reactions during combustion is spread through three extended catalytic regimes along the isothermal ceramic device. It is evident that ceramic burners are necessary to provide catalytic activity and to promote electron transfer. The conclusion is that ceramic will ultimately replace metal in burners requiring low emissions and high exergy output.     

Nuclear Morphometry in Normal and SV-40 Transformed Human Diploid Fibroblasts

These experiments were designed to compare the densitometric, morphometric, and texture characteristics of intact nuclei from stationary WI-38 human diploid fibroblasts and their stationary SV40-transformed counterparts (2RA cells) by means of automated image analysis and to compare the differences in template activity of the chromatins isolated from the two cell lines. While the frequency distributions of directly measured parameters as area and IOD show a substantial overlap between WI-38 and 2RA cells, average optical density parameter derived as IOD per unit area, yields two distinctly separated distributions, which permit objective identifications of individual SV40 transformed cells. Chromatin of the stationary 2RA cells appears more condensed than that of the confluent WI-38 cells, quite compatible with the decreased template activity of chromatin from transformed cells.     

Alarm reaction in acquisition and social transmission of simulated-predator recognition by zebra danio fish (Brachydanio rerio).

Alarm reactions occur in response to alarm substance passively released by injury to skin of zebra danio fish (Brachydanio rerio). Visual observation of alarmed conspecifics yields socially facilitated alarm by observers. Concurrent exposure of fish to alarm substance and a novel odorant (morpholine) later produced learned alarm to morpholine alone. Fish trained with morpholine plus alarm substance were mixed in with naive fish for a test with morpholine alone. The naive fish, separated out from the mixed groups, then demonstrated not only an acquired alarm reaction to morpholine but also an ability to communicate the acquired recognition of a simulated predator to a new group of naive observers. The results suggest the operation of a sophisticated antipredator defensive system in zebra danios that involves unlearned releasing stimuli, social facilitation, visual communication, learned predator recognition, and social communication of predator recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)