scholarly journals Challenge Test Improvement: Analytical Costs and Time Optimization

2017 ◽  
Vol 1 (2) ◽  
pp. 100
Author(s):  
Marco Romani ◽  
Chiara Romani
Keyword(s):  
Listeria Monocytogenes ◽  
Growth Parameters ◽  
Challenge Test ◽  
Assessment Model ◽  
Quantitative Risk Assessment ◽  
Test Results ◽  
Proposed Model ◽  
Plate Counts ◽  
Daily Concentration ◽  
Lactobacillus Spp

<p><em>The study’s aim was to develop a quantitative risk assessment model of Listeria monocytogenes in liver chicken paté. The model was performed using the Integrated Challenge Test (Italian Journal of Food Safety, Vol. 1 N. 6 2012) with the objective to reduce the analytical cost and time. The challenge test was carried out on 3 different batches stored at 12°C and inoculated with a mix of Listeria monocytogenes strains. Lactobacillus spp. and Listeria monocytogenes plate counts were performed daily on each sample until the stationary phase was reached by both populations. The challenge test results at 12°C were input in the Combase DMfit software to determine the growth parameters of Listeria monocytogenes and lactic flora which showed mutual interaction. Then, using the Combase Predictor for Listeria monocytogenes and the FSSP (Food Spoilage and Safety Predictor) software for lactic flora, the growth parameters were extrapolated at 4°C and 8°C. The growth parameters of both populations at 4°C, 8°C and 12°C were then used to apply the model in order to predict the maximum daily concentration of Listeria monocytogenes. Model results were assessed against the results of an additional challenge test conducted with the same strain mix inoculum in 3 different batches stored for 4 days at 4°C, 4 days at 8°C and then 4 days at 12°C. The proposed model represents a reliable quantitative risk evaluation which provides realistic results with limited cost.</em></p>

A New Risk Assessment Model to Check Safety Threats to Long-Distance Pipelines

2021 ◽  
Author(s):  
Duhui Lu ◽  
Guangpei Cong ◽  
Bing Li
Keyword(s):  
Risk Assessment ◽  
Protective Layer ◽  
Assessment Model ◽  
Quantitative Risk Assessment ◽  
Risk Assessment Model ◽  
Long Distance ◽  
Proposed Model ◽  
Integrity Management ◽  
Current Assessment ◽  
Inspection Data

Abstract With the number of long-distance pipelines increasing in China, risk management has become important for controlling pipeline leakage. However, all the current assessment technologies are semi-quantitative and do not include inspection data. To address this problem, a new quantitative risk assessment model is proposed to guide decision-making on excavation inspection and maintenance. Based on previous failure cases, the model includes data about the surrounding soils as well as about the pipeline's protective layer, cathodic protection and thickness readings. Testing of the proposed model on previous failure cases shows that the new model can correctly assess the real leakage risk of a long-distance pipeline and support the quantitative integrity management of a long-distance pipeline during its whole service life.

Quantitative Risk Assessment for Listeria monocytogenes in Selected Categories of Deli Meats: Impact of Lactate and Diacetate on Listeriosis Cases and Deaths

2009 ◽  
Vol 72 (5) ◽  
pp. 978-989 ◽  
Author(s):  
ABANI K. PRADHAN ◽  
RENATA IVANEK ◽  
YRJÖ T. GRÖHN ◽  
IFIGENIA GEORNARAS ◽  
JOHN N. SOFOS ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Listeria Monocytogenes ◽  
Specific Growth ◽  
Growth Parameters ◽  
The United States ◽  
Quantitative Risk Assessment ◽  
Health Concern ◽  
Lag Phase ◽  
Growth Inhibitors ◽  
The U.S

Foodborne disease associated with consumption of ready-to-eat foods contaminated with Listeria monocytogenes represents a considerable pubic health concern. In a risk assessment published in 2003, the U.S. Food and Drug Administration and the U.S. Food Safety and Inspection Service estimated that about 90% of human listeriosis cases in the United States are caused by consumption of contaminated deli meats. In this risk assessment, all deli meats were grouped into one of 23 categories of ready-to-eat foods, and only the postretail growth of L. monocytogenes was considered. To provide an improved risk assessment for L. monocytogenes in deli meats, we developed a revised risk assessment that (i) models risk for three subcategories of deli meats (i.e., ham, turkey, and roast beef) and (ii) models L. monocytogenes contamination and growth from production to consumption while considering subcategory-specific growth kinetics parameters (i.e., lag phase and exponential growth rate). This model also was used to assess how reformulation of the chosen deli meat subcategories with L. monocytogenes growth inhibitors (i.e., lactate and diacetate) would impact the number of human listeriosis cases. Use of product-specific growth parameters demonstrated how certain deli meat categories differ in the relative risk of causing listeriosis; products that support more rapid growth and have reduced lag phases (e.g., turkey) represent a higher risk. Although reformulation of deli meats with growth inhibitors was estimated to reduce by about 2.5- to 7.8-fold the number of human listeriosis cases linked to a given deli meat subcategory and thus would reduce the overall risk of human listeriosis, even with reformulation deli meats would still cause a considerable number of human listeriosis cases. A combination of strategies is thus needed to provide continued reduction of these cases. Risk assessment models such as that described here will be critical for evaluation of different control approaches and to help define the combinations of control strategies that will have the greatest imp–ct on public health.

scholarly journals Listeria monocytogenes in Retail Delicatessens: An Interagency Risk Assessment—Risk Mitigations

2016 ◽  
Vol 79 (7) ◽  
pp. 1076-1088 ◽  
Author(s):  
DANIEL GALLAGHER ◽  
RÉGIS POUILLOT ◽  
KARIN HOELZER ◽  
JIA TANG ◽  
SHERRI B. DENNIS ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Growth Inhibitor ◽  
Health Impact ◽  
Mitigation Strategies ◽  
Assessment Model ◽  
Quantitative Risk Assessment ◽  
Cross Contamination ◽  
Baseline Conditions

ABSTRACT Cross-contamination, improper holding temperatures, and insufficient sanitary practices are known retail practices that may lead to product contamination and growth of Listeria monocytogenes. However, the relative importance of control options to mitigate the risk of invasive listeriosis from ready-to-eat (RTE) products sliced or prepared at retail is not well understood. This study illustrates the utility of a quantitative risk assessment model described in a first article of this series (Pouillot, R., D. Gallagher, J. Tang, K. Hoelzer, J. Kause, and S. B. Dennis, J. Food Prot. 78:134–145, 2015) to evaluate the public health impact associated with changes in retail deli practices and interventions. Twenty-two mitigation scenarios were modeled and evaluated under six different baseline conditions. These scenarios were related to sanitation, worker behavior, use of growth inhibitors, cross-contamination, storage temperature control, and reduction of the level of L. monocytogenes on incoming RTE food products. The mean risk per serving of RTE products obtained under these scenarios was then compared with the risk estimated in the baseline condition. Some risk mitigations had a consistent impact on the predicted listeriosis risk in all baseline conditions (e.g. presence or absence of growth inhibitor), whereas others were greatly dependent on the initial baseline conditions or practices in the deli (e.g. preslicing of products). Overall, the control of the bacterial growth and the control of contamination at its source were major factors of listeriosis risk in these settings. Although control of cross-contamination and continued sanitation were also important, the decrease in the predicted risk was not amenable to a simple solution. Findings from these predictive scenario analyses are intended to encourage improvements to retail food safety practices and mitigation strategies to control L. monocytogenes in RTE foods more effectively and to demonstrate the utility of quantitative risk assessment models to inform risk management decisions.

In-Plane Flexible Ring Tire Model—Part 1: Modeling and Parameter Identification

2018 ◽  
Vol 46 (3) ◽  
pp. 174-219 ◽  
Author(s):  
Bin Li ◽  
Xiaobo Yang ◽  
James Yang ◽  
Yunqing Zhang ◽  
Zeyu Ma
Keyword(s):  
Static Load ◽  
Model Parameters ◽  
Tire Model ◽  
Test Results ◽  
Lumped Mass ◽  
Virtual Test ◽  
Proposed Model ◽  
Particle Swarm Method ◽  
Vehicle Dynamic Simulation ◽  
Flexible Ring

ABSTRACT The tire model is essential for accurate and efficient vehicle dynamic simulation. In this article, an in-plane flexible ring tire model is proposed, in which the tire is composed of a rigid rim, a number of discretized lumped mass belt points, and numerous massless tread blocks attached on the belt. One set of tire model parameters is identified by approaching the predicted results with ADAMS® FTire virtual test results for one particular cleat test through the particle swarm method using MATLAB®. Based on the identified parameters, the tire model is further validated by comparing the predicted results with FTire for the static load-deflection tests and other cleat tests. Finally, several important aspects regarding the proposed model are discussed.

A semi-quantitative risk assessment model for the outbreak of grass carp hemorrhage

2013 ◽  
Vol 19 (3) ◽  
pp. 521-527 ◽  
Author(s):  
Song YANG ◽  
Shuqin WU ◽  
Ningqiu LI ◽  
Cunbin SHI ◽  
Guocheng DENG ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Grass Carp ◽  
Assessment Model ◽  
Quantitative Risk Assessment ◽  
Risk Assessment Model

Higher-Order Thinking Skills (HOTS)-based Formative Assessment: A Proposed Model for Language Learning Assessment

2020 ◽  
Vol 9 (2) ◽  
pp. 115
Author(s):  
Wiyaka Wiyaka ◽  
Entika Fani Prastikawati ◽  
AB Prabowo Kusumo Adi
Keyword(s):  
Formative Assessment ◽  
Language Learning ◽  
Higher Order Thinking ◽  
Thinking Skills ◽  
Higher Order ◽  
Formative Assessments ◽  
Assessment Model ◽  
Higher Order Thinking Skills ◽  
Learning Assessments ◽  
Proposed Model

<div><p class="StyleABSTRAKenCambria">The integration of higher-order thinking skills (HOTS) in language learning assessments has become a crucial issue in 21st-century learning. However, not many teachers are aware of the need to incorporate HOTS in assessments due to their insufficient knowledge and the absence of good examples. Further, there is not much research and literature on HOTS-based formative assessment that can be used as references. This research aims to fill the existing gap by providing a model of higher-order thinking skills (HOTS)-based formative assessments for English learning, especially in junior high schools. By employing research and development design, this research describes the validation of the assessment model. The proposed model of assessment may be used as a prototype for assessing language learning.</p></div><p> </p>

Using Indicator Bacteria and Salmonella Test Results from Three Large-Scale Beef Abattoirs over an 18-Month Period To Evaluate Intervention System Efficacy and Plan Carcass Testing for Salmonella

2007 ◽  
Vol 70 (12) ◽  
pp. 2732-2740 ◽  
Author(s):  
JOHN R. RUBY ◽  
JUN ZHU ◽  
STEVEN C. INGHAM
Keyword(s):  
Lactic Acid ◽  
Large Scale ◽  
Microbial Contamination ◽  
Test Results ◽  
Microbiological Contamination ◽  
Negative Results ◽  
Intervention Process ◽  
Beef Carcasses ◽  
Causative Factors ◽  
Plate Counts

To develop a process for predicting the likelihood of Salmonella contamination on beef carcasses, we evaluated the influence of several possible causative factors (i.e., year, abattoir, day of week, month, and intervention system components) on the risk of Salmonella and indicator organism contamination. Hide and carcass sponge samples were collected in 2005 to 2006 in six steps at three abattoirs in the East (A), Midwest (B), and Southwest (C) United States. Each abattoir used the same intervention system. Samples were analyzed for aerobic plate counts (APCs; n = 18,990) and Enterobacteriaceae counts (EBCs; n = 18,989) and the presence or absence of Salmonella (n = 5,355). Our results demonstrated that many factors play a significant role in the level of microbial contamination of beef carcasses. Overall, Salmonella prevalence and EBC levels were significantly higher in 2006 than in 2005. APCs and EBCs were highest in abattoirs A (3.57 log CFU/100 cm2) and B (1.31 log CFU/100 cm2). The odds of detecting a positive Salmonella isolate were greatest in abattoir C and lowest in abattoir A. Across the three abattoirs, the overall intervention process effectively reduced microbiological contamination. Salmonella prevalence fell from 45% (preevisceration) to 0.47% (postchilled–lactic acid), and there were APC and EBC reductions of 5.43 and 5.28 log CFU/100 cm2, respectively, from hide-on to postchilled–lactic acid samples. At each abattoir, composites of three individual EBC-negative carcass samples yielded Salmonella-negative results 97 to 99% of the time. These results suggest the possibility of using indicator test results to accurately predict the absence of Salmonella in a beef carcass sample.

Power Transformer Fault Diagnosis Based on Vibration Correlation Analysis

2014 ◽  
Author(s):  
Kaixing Hong ◽  
Hai Huang
Keyword(s):  
Fault Diagnosis ◽  
Correlation Analysis ◽  
Fundamental Frequency ◽  
Vibration Analysis ◽  
Laboratory Tests ◽  
Power Transformer ◽  
Assessment Model ◽  
Vibration Method ◽  
Proposed Model ◽  
Transformer Fault

In this paper, a condition assessment model using vibration method is presented to diagnose winding structure conditions. The principle of the model is based on the vibration correlation. In the model, the fundamental frequency vibration analysis is used to separate the winding vibration from the tank vibration. Then, a health parameter is proposed through the vibration correlation analysis. During the laboratory tests, the model is validated on a test transformer, and manmade deformations are provoked in a special winding to compare the vibrations under different conditions. The results show that the proposed model has the ability to assess winding conditions.

scholarly journals PROPOSING A NEW METHODOLOGY BASED ON FUZZY LOGIC FOR TUNNELLING RISK ASSESSMENT

2014 ◽  
Vol 20 (1) ◽  
pp. 82-94 ◽  
Author(s):  
Abdolreza Yazdani-Chamzini
Keyword(s):  
Risk Assessment ◽  
Fuzzy Inference ◽  
Assessment Model ◽  
Tunnel Construction ◽  
Construction Operations ◽  
Protective Measures ◽  
Inference System ◽  
Proposed Model ◽  
Mine Development ◽  
Civil Defence

Tunnels are artificial underground spaces that provide a capacity for particular goals such as storage, under-ground transportation, mine development, power and water treatment plants, civil defence. This shows that the tunnel construction is a key activity in developing infrastructure projects. In many situations, tunnelling projects find themselves involved in the situations where unexpected conditions threaten the continuity of the project. Such situations can arise from the prior knowledge limited by the underground unknown conditions. Therefore, a risk analysis that can take into account the uncertainties associated with the underground projects is needed to assess the existing risks and prioritize them for further protective measures and decisions in order to reduce, mitigate and/or even eliminate the risks involved in the project. For this reason, this paper proposes a risk assessment model based on the concepts of fuzzy set theory to evaluate risk events during the tunnel construction operations. To show the effectiveness of the proposed model, the results of the model are compared with those of the conventional risk assessment. The results demonstrate that the fuzzy inference system has a great potential to accurately model such problems.

Quantitative Risk Assessment of Listeria monocytogenes in Smoked and Raw Salmon

2021 ◽  
Vol 36 (2) ◽  
pp. 124-134
Author(s):  
Ki Young Song ◽  
◽  
So Young Yang ◽  
Eun Woo Lee ◽  
Ki Sun Yoon
Keyword(s):  
Risk Assessment ◽  
Listeria Monocytogenes ◽  
Quantitative Risk Assessment
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