Critical review of mathematical approaches for quantitative microbial risk assessment (QMRA) of Legionella in engineered water systems: research gaps and a new framework

2016 ◽  
Vol 2 (4) ◽  
pp. 599-613 ◽  
Author(s):  
K. A. Hamilton ◽  
C. N. Haas
Keyword(s):  
Risk Assessment ◽  
Disease Outbreaks ◽  
The United States ◽  
Water Systems ◽  
Quantitative Microbial Risk Assessment ◽  
Research Gaps ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Systems Research ◽  
New Framework

Legionellahas been identified as the responsible agent for two-thirds of waterborne disease outbreaks in the United States from 2011–2012.

scholarly journals Evaluating the Risk of Salmonellosis from Dry Roasted Sunflower Seeds

2019 ◽  
Vol 83 (1) ◽  
pp. 17-27 ◽  
Author(s):  
BALASUBRAHMANYAM KOTTAPALLI ◽  
STEPHANIE P. V. NGUYEN ◽  
KELLY DAWSON ◽  
KAITLYN CASULLI ◽  
CATE KNOCKENHAUER ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Water Activity ◽  
The United States ◽  
Arithmetic Mean ◽  
Assessment Model ◽  
Quantitative Microbial Risk Assessment ◽  
Sunflower Seeds ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Log Reduction

ABSTRACT Outbreaks and recalls related to nuts and seeds in the United States have increased recently, and 80% of these recalls are due to Salmonella. The U.S. Food and Drug Administration's Food Safety Modernization Act requires food manufacturers to implement risk-based preventive controls based on scientific and technical evidence. Data are limited on the inactivation of Salmonella during processing of saltwater brined in-shell sunflower seeds. The goal of this research was to validate the adequacy of roasting in controlling Salmonella during the production of sunflower seeds and to assess the resulting risk. Four Salmonella strains were inoculated onto sunflower seeds and processed to simulate commercial manufacturing. Seeds were tumbled and roasted at 225°F (107.2°C) and 275°F (135°C) for roasting times from 5 to 45 min. Regression models for Salmonella inactivation and water activity change were developed. The inactivation model predicted a 5-log reduction in Salmonella when sunflower seeds were roasted at 135°C for 19.2 min, with a corresponding water activity of ∼0.61. Roasted sunflower seeds are typically not saleable at water activities >0.6 due to quality issues. Saleable water activities (0.03 to 0.04) were only achieved when the sunflower seeds were roasted for 45 min at 135°C, which resulted in a >7-log reduction in Salmonella. A quantitative microbial risk assessment based on literature values, expert opinion, and the above-mentioned models was used to predict risk of salmonellosis from sunflower seeds. The quantitative microbial risk assessment model predicted an arithmetic mean probability of illness of 1.45E−07 per 28-g serving based on roasting at 135°C for 20 min and an arithmetic mean probability of illness of 5.46E−10 per serving based on roasting at 135°C for >45 min (i.e., saleable product process parameters). This study demonstrates that sunflower seeds roasted to saleable parameters should not represent a public health risk from potential presence of Salmonella.

Quantitative microbial risk assessment of Salmonella and Enterococcus in Marina Reservoir and catchments

2015 ◽  
Vol 10 (3) ◽  
pp. 527-531 ◽  
Author(s):  
S. G. Goh ◽  
H. M. Fang ◽  
S. Y. Chang ◽  
Karina Y. H. Gin
Keyword(s):  
Risk Assessment ◽  
Environmental Protection Agency ◽  
The United States ◽  
Quantitative Microbial Risk Assessment ◽  
Salmonella Spp ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Simulation Techniques ◽  
Guideline Values ◽  
Microbial Risks

This study assesses the infection risks associated with non-swimming recreational activities in Marina Reservoir, Singapore. Apart from serving as a reservoir for potable water use, Marina Reservoir is also a place where various water recreations are carried out. Quantitative microbial risk assessment (QMRA) was applied to Marina Reservoir and its four main feeders. QMRA was performed based on the occurrence data of the potential pathogen, Salmonella spp. and bacteria indicator, Enterococcus spp. through Monte Carlo simulation techniques. The results suggest that microbial risks from Salmonella and Enterococcus at the reservoir were below the United States Environmental Protection Agency (USEPA) acceptable freshwater recreational illness rate of 0.8%. All upstream catchments showed acceptable microbial risks from Salmonella. However, the probability of gastrointestinal illness risks calculated for Enterococcus exceeded the USEPA guideline values in one of the upstream catchments, but far enough upstream from recreational areas that are used frequently.

Quantifying the Risk of Human Toxoplasma gondii Infection Due to Consumption of Domestically Produced Lamb in the United States

2016 ◽  
Vol 79 (7) ◽  
pp. 1181-1187 ◽  
Author(s):  
MIAO GUO ◽  
ABHINAV MISHRA ◽  
ROBERT L. BUCHANAN ◽  
JITENDER P. DUBEY ◽  
DOLORES E. HILL ◽  
...  
Keyword(s):  
Public Health ◽  
United States ◽  
Risk Assessment ◽  
Toxoplasma Gondii ◽  
The United States ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Public Health Burden ◽  
Health Burden

ABSTRACT Toxoplasma gondii is a prevalent protozoan parasite worldwide. Human toxoplasmosis is responsible for considerable morbidity and mortality in the United States, and meat products have been identified as an important source of T. gondii infections in humans. The goal of this study was to develop a farm-to-table quantitative microbial risk assessment model to predict the public health burden in the United States associated with consumption of U.S. domestically produced lamb. T. gondii prevalence in market lambs was pooled from the 2011 National Animal Health Monitoring System survey, and the concentration of the infectious life stage (bradyzoites) was calculated in the developed model. A log-linear regression and an exponential dose-response model were used to model the reduction of T. gondii during home cooking and to predict the probability of infection, respectively. The mean probability of infection per serving of lamb was estimated to be 1.5 cases per 100,000 servings, corresponding to ~6,300 new infections per year in the U.S. population. Based on the sensitivity analysis, we identified cooking as the most effective method to influence human health risk. This study provided a quantitative microbial risk assessment framework for T. gondii infection through consumption of lamb and quantified the infection risk and public health burden associated with lamb consumption.

Modeling the Risk of Salmonellosis from Consumption of Peanuts in the United States

2019 ◽  
Vol 82 (4) ◽  
pp. 579-588 ◽  
Author(s):  
KAITLYN E. CASULLI ◽  
STEPHEN CALHOUN ◽  
DONALD W. SCHAFFNER
Keyword(s):  
United States ◽  
Risk Assessment ◽  
Geometric Mean ◽  
The United States ◽  
Economic Losses ◽  
Quantitative Microbial Risk Assessment ◽  
Concentration Data ◽  
Modeling Tools ◽  
Microbial Risk Assessment ◽  
Microbial Risk

ABSTRACT Peanut products were the target of the largest food recall in United States history from 2008 to 2009, with more than 3,200 products implicated, economic losses estimated at $1 billion, and more than 700 reported illnesses and 9 deaths. Predictive modeling tools such as quantitative microbial risk assessment can be used to aid processors in making risk management decisions that may reduce the chances of foodborne illness, but published risk assessment for peanuts is not currently available. A quantitative microbial risk assessment was performed to quantify salmonellosis risk from consumption of peanuts in the United States. Prevalence and concentration data for Salmonella on raw, shelled peanuts were used in combination with probability distributions of simulated log reductions achieved during production steps before consumption. Data for time-temperature combinations used in each step were obtained from published literature, industry surveys, or expert opinion, and survival data were obtained from the literature. A beta-Poisson dose-response model was used to predict probability of illness from ingestion of Salmonella cells. The model predicted 14.2 (arithmetic mean) or 0.0123 (geometric mean) illnesses per year. Sensitivity analysis showed that thermal inactivation log reductions applied had the biggest impact on predicted salmonellosis risk, followed by consumer storage time, Salmonella starting concentration, Salmonella starting prevalence, and number of originally contaminated 25-g servings per originally positive 375-g sample. Scenario analysis showed that increasing log reduction variability increased mean salmonellosis risk. Removing the effect of storage on Salmonella survival increased the arithmetic and geometric means to 153 and 0.598 illnesses per year, respectively. This study indicated that the risk of salmonellosis from consumption of peanuts can be lowered by reducing field contamination, control of storage steps, and monitoring of appropriate critical limits in peanut roasting.

scholarly journals Use of microbial risk assessment to inform the national estimate of acute gastrointestinal illness attributable to microbes in drinking water

2006 ◽  
Vol 4 (S2) ◽  
pp. 165-186 ◽  
Author(s):  
Jeffrey A. Soller
Keyword(s):  
Risk Assessment ◽  
Drinking Water ◽  
Distribution Systems ◽  
The United States ◽  
Water Systems ◽  
Gastrointestinal Illness ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Acute Gastrointestinal Illness ◽  
Treated Drinking Water

Microbial risk assessment (MRA) evaluates the likelihood of adverse human health effects that occur following exposure to pathogenic microorganisms. This paper focuses on the potential use of MRA to provide insight to the national estimate of acute gastrointestinal illness (AGI) in the United States among persons served by public water systems. This article defines MRA, describes how MRA is implemented, provides an overview of the field of MRA and discusses how MRA may be useful for characterizing the national estimate. Communities served by drinking water systems with relatively contaminated source waters, sub-standard treatment facilities, and/or contamination problems in their distribution systems are subject to higher risks than communities where such issues are less of a concern. Further, the risk of illness attributable to pathogens in drinking water in each community can be thought of as the sum of the risk from the treated drinking water and the risk from the distribution system. Pathogen-specific MRAs could be developed to characterize the risk associated with each of these components; however, these assessments are likely to under-estimate the total risk from all pathogens attributable to drinking water. Potential methods for developing such MRAs are discussed along with their associated limitations.

Enteric virus presence in green vegetables and associated irrigation waters in a rural area from Argentina. A quantitative microbial risk assessment

LWT ◽  
2021 ◽  
Vol 144 ◽  
pp. 111201 ◽  
Author(s):  
Prez Verónica Emilse ◽  
Victoria Matías ◽  
Martínez Laura Cecilia ◽  
Giordano Miguel Oscar ◽  
Masachessi Gisela ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Rural Area ◽  
Enteric Virus ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Irrigation Waters
Sign in / Sign up

Export Citation Format

Share Document