**-  North Atlantic  
-  Eastern Regional Rsch. Ctr. 
-  Microbial Food Safety Research Unit 
Printable VersionE-mail this pageThis site onlyAll ARS Advanced Search UBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">		You are here: 						Research / 																				**Research Project:**Microbial Modeling and Bioinformatics for Food Safety and Security
**Location: Microbial Food Safety Research Unit**
**2006 Annual Report**
**1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)?  How serious is the problem?  Why does it matter?**													Each year, it is estimated that more than 76,000,000 infections are linked to the consumption of contaminated foods, with an associated 5,000 deaths and an economic impact exceeding $5,000,000,000 USD. Such contamination can occur at many points in the food production system, on the farm, at processing plants, during transportation, at wholesale and retail levels, and during consumer handling. Fortunately, the risk of foodborne disease can be reduced by designing and implementing food processing and handling interventions that control, reduce and/or eliminate foodborne pathogens.
Regulatory agencies, such as the Food & Drug Administration (FDA) and the USDA Food Safety & Inspection Service (FSIS), utilize quantitative microbial risk assessment (QMRA) to determine interventions that provide the most effective means of reducing the risk of foodborne disease. In the food industry, such interventions are part of Hazard Analysis & Critical Control Points (HACCP) food safety systems. However, the scientific and fiscal resources needed to determine the appropriate critical points and associated safe processing parameters many times exceed the resources of food companies, especially that of small and very small FSIS-inspected operations. For these reasons, predictive models present efficient solutions to the development of HACCP plans and in the production of risk assessment, thus permitting risk managers to estimate the behavior of pathogens over a wide range of diverse processing and handling conditions.
This project solves many of these problems by providing models that describe the behavior of major pathogens in higher risk marketplace foods, including scenarios for pathogen growth, virulence expression, death and transfer among food processing surfaces. Furthermore, we will decrease the uncertainty of model predictions by identifying cellular markers associated with the physiological state of the pathogen and thus the length of the bacterial lag phase. To enhance the transfer of these technologies, we will measure the bias and accuracy of models and describe their performance for various categories of foods, thereby assisting food industries and risk assessors in determining which modeling tools best meet their needs. This will facilitate the use of more models in HACCP systems and lead to greater acceptance of models by regulators and the food industry. We anticipate that the development of these new models into a process model format will also accelerate their integration into HACCP operations, allowing users to estimate the effects of various interventions throughout a series of food processing operations.
The specific objectives for this project are.1)to evaluate, validate, and where necessary, develop new innovative, robust and valid predictive models for the responses of microbial pathogens, including foodborne threat agents, in select food matrices, as a function of: temperature, food formulation, competitive microflora, physiological history, and surface transfer,.2)to develop novel approaches to assess model performance and robustness, leading to more efficient strategies for producing and extrapolating models to different classes of food, and.3)to determine the probability distribution of lag phase duration (LPD) for foodborne pathogens, as a function of the previous bacterial physiological history, to and identify molecular markers that discriminate bacterial lag, growth and stationary phases.
The proposed research is relevant to Sections 1.2.7 (Risk Assessment) and 1.2.9 (Food Security) in the 2006-2010 NP 108 Action Plan. The proposed work addresses ARS research priorities for improved QMRA through more accurate exposure assessment and risk characterization; for development of robust and validated process risk models that address hazards in complex food matrices; and for validated models that predict the effect of specific intervention strategies on threat agents. Furthermore, the project plan will result in user-friendly simulation models which will be used by industry and regulatory agencies to assess the impact of foodborne pathogens on public health.						
**2.List by year the currently approved milestones (indicators of research progress)**													FY 2006Complete prototype ground beef microbial community model.
Complete data collection for growth of Yersinia spp. in ground beef and pork
Complete measurements of E. sakazakii LPD
Complete E. coli O157:H7 - fermented sausage models
Complete a model for the inactivation of B. anthracis and L. monocytogenes in ground beef, and model for the fate of C. perfringens during the cooling of uncured beef
Complete measurements of E. coli O157:H7 surface transfer coefficients
Complete robustness indices (RI) for E. coli in beef
Complete E. sakazaki infant formula growth model
FY2007Complete prototype ham microbial community model
Complete data collection for Yersinia spp. plasmid stability in ground beef and pork
Complete E. coli O157:H7 LPD distribution models
Complete models of L. monocytogenes, Salmonella in fermented sausage; L. monocytogenes in ham and meat salad
Complete production of a predictive model for thermal inactivation of E. coli O157:H7 in beef and a model of C. perfringens growth applicable to the cooling of uncured pork.
Complete studies of L. monocytogenes transfer
Complete measurements of RI for Salmonella in beef
Complete E. sakazaki data collection for survival in dry infant dry formula
FY2008Produce models for microbial competition in ground beef and ham
Transfer Yersinia spp. models to PMP and ComBase
Complete probability distribution models for L. monocytogenes LPD
Complete identification of E. coli K12 DNA LPD markers
Complete models of L. monocytogenes in smoked seafood
Complete models of C. perfringens survival during cooling of cooked poultry
Complete measurements of Salmonella surface transfer coefficients
Complete RI for L. monocytogenes in deli meats and salads
Complete E. sakazaki consumer practice LPD models
FY2009Validate models
Complete analyses of RNA markers
Validate fermented sausages, smoked seafood and meat/ham salad models
Complete studies of Salmonella inactivation, and survival during cooling and storage
Validate Salmonella, E. coli and L. monocytogenes models
Complete translation of model uncertainty into exposure levels
Transfer models via PMP and ComBase
FY2010
Transfer models via PMP and ComBase
Complete analyses of protein markers
Validate models and transfer models via PMP and ComBase
Complete process risk mode, transfer models to PMP and ComBase
Transfer models to PMP

**4a.List the single most significant research accomplishment during FY 2006.**													This project recently completed the NP 108 OSQR Review Process and was certified.  See the report for 1935-42000-050-00D.						
**4b.List other significant research accomplishment(s), if any.**													This project recently completed the NP 108 OSQR Review Process and was certified.  See the report for 1935-42000-050-00D.						
**4c.List significant activities that support special target populations.**													This project recently completed the NP 108 OSQR Review Process and was certified.  See the report for 1935-42000-050-00D.						
**4d.Progress report.**													1935-42000-057-01G:  This report serves to document research conducted under a General Assistance Type agreement between ARS and the University of Arkansas.  There is a great need for validated models to predict the thermal inactivation of L. monocytogenes and to assist the food industry in implementing in-plant heat pasteurization of packaged, fully cooked poultry and meat products. Researchers at the University of Arkansas and the ARS Eastern Regional Research Center in Wyndmoor, PA are validating a predictive model of heat and mass transfer with pathogen kinetics to predict pathogen kill as a function of time, moisture, and temperature, and designing treatment schedules to achieve the targeted pathogen log-reduction on various sizes and shapes of poultry products that are processed in different commercial steam or hot water cookers, followed by cooling. The research products support the Project Plan and will result in more accurate thermal food processes to minimize risks caused by L. monocytogenes.
1935-42000-057-02G:  This report serves to document research conducted under a General Assistance Type of agreement between ARS and the University of Georgia. The doses of L. monocytogenes that result in human listeriosis are not known, primarily because human experimental studies cannot be conducted. Researchers at the University of Georgia and the ARS Eastern Regional Research Center in Wyndmoor, PA are using pregnant guinea pigs to develop dose response information for L. monocytogenes-induced human stillbirths and/or abortions. This will be done by.1)determining the region of dose-response overlap with the existing non-human primate study,.2)determining the dose-response for adverse fetal effect after maternal exposure to L. monocytogenes,.3)defining endpoints that predict adverse pregnant outcomes such as L. monocytogenes invasion of maternal liver, maternal spleen, placenta and fetus, and.4)comparing the dose response curve developed in pregnant guinea pigs to mouse, primate and human dose response curves. This research supports the Project plan by producing dose response models that more accurately estimate infective doses of L. monocytogenes.
1935-42000-057-03G:  This report serves to document research conducted under a General Assistance type of agreement between ARS and Purdue University. Researchers at Purdue University and the ARS Eastern Regional Research Center in Wyndmoor, PA are developing realistic and accurate predictive models for the thermal inactivation of L. monocytogenes in processed RTE meats. This will be accomplished by studying and comparing thermal inactivation models for L. monocytogenes grown under stress conditions in low and high fat hot dogs (10 to 30%), in conditions to simulate its presence in water and residual sanitizers, and in tryptic soy broth. This will be done by.1)comparing surface thermal inactivation models over a range of post-processing temperatures relevant to industrial practices for L. monocytogenes in hot dogs made with and without combinations of sodium diacetate and potassium lactate as currently used in the industry,.2)by determining thermal inactivation of L. monocytogenes on hot dogs surface-sprayed with different combinations of sodium diacetate and potassium lactate, and.3)by validating the new models against the experimental data for inactivation of L. monocytogenes in hot dogs using the growth medium that represents high and low D-values and sprayed lactate/diacetate formulations. This research supports the Project Plan by producing technologies that can be transferred to food companies, food regulators and risk assessors to design more effective processing controls to minimize the risks of listeriosis.
1935-42000-057-04G:  This report serves to document research conducted under a General Assistance type of agreement between ARS and Michigan State University. Little is known about the effects of temperature and relative humidity on growth and die-off of L. monocytogenes on high density polyethylene (HDPE) and polyurethane (PU) conveyor belt surfaces used in processing plants. Researchers at Michigan State University and the ARS Eastern Regional Research Center in Wyndmoor, PA are assessing the impact of food contact material, inoculum level, product moisture content, contact time and contact pressure on transfer coefficients for L. monocytogenes from surface-contaminated hams to HDPE and PU and vice versa, determine a series of transfer coefficients for L. monocytogenes from inoculated HDPE and PU contact surfaces to ham and vice versa, and develop a mathematical model based on data from the previous objectives that will express and quantify transfer potentials for listeria cross contamination within the food processing environment. This research supports the Project Plan by producing process risk models that can be transferred to food companies, regulators and risk assessors to predict the movement of pathogens among food processing surfaces.
1935-42000-057-05R:  This report serves to document research conducted under a Reimbursible Cooperative Agreement between ARS and the University of Nebraska.  Funds were received for research on developing and validating models during cooking and cooling of cooked products.   In order to carry out the research, studies were conducted under 1935-42000-057-00 D to determine the growth of C. perfringens in 75% lean beef, pork and poultry at various temperatures ranging from 10C to 50C.   Collection of data was completed and a predictive model for the disposition of products subject to cooling deviations was developed.   The model will be incorporated in the ARS-Pathogen Modeling Program.
1935-42000-057-07R:  This report serves to document research conducted under a Reimbursible Cooperative Agreement between ARS and the University of Nebraska.   Funds were received for research on developing and validating models during chilling of carcasses.   In order to carry out the research, studies were conducted under 1935-42000-057-00 D to model the effect of  temperatures on growth of Salmonella in beef and chicken at various temperatures ranging from 5C to 50C.   Two predictive models applicable to the chilling of meat animal carcasses have been developed.  These models will be incorporated in the ARS-Pathogen Modeling Program. 
1935-42000-057-08R:  This report serves to document research conducted between ARS and the University of Wisconsin.  Validated predictive models for pathogen growth in meat and poultry products are not available.  Researchers at the University of Wisconsin and the ARS Eastern Regional Research Center in Wyndmoor, PA integrate research in three areas: short-term temperature abuse of uncooked meat and poultry products, slow-cooking and/or fermentation of meat and poultry products, and low-heat processing of ready-to-eat meat and poultry products. The research product support the CRIS project plan and will provide data to meet Critical Limit validation needs of meat and poultry processors for use in validation and verification of their HACCP plans.
1935-42000-057-09R:  This report serves to document research conducted under a Reimbursable agreement between ARS and USDA Food Safety Inspection Service. Predictive models allow food safety managers to forecast the fate of pathogens in food processing operations, however many small and very small processors require additional support in the use and interpretation of models. The FSIS Division of Outreach and Strategic Partnerships in Washington, DC and the ARS Eastern Regional Research Center in Wyndmoor, PA are developing a Predictive Microbiology Information Portal that provides on-line models, research data and background information for food safety applications. This research supports the Project Plan by enhancing the transfer of predictive microbiology technology to food companies for use in food safety management.
1935-42000-057-10R:  This report serves to document research conducted under a Reimbursable Cooperative agreement between ARS and USDA Food Safety and Inspection Service. Behavior of Yersinia pestis in raw and cooked ground beef and Bacillus anthracis Sterne in cooked ground beef were characterized.  The thermal resistance (D-values in min) of Y. pestis in ground beef ranged from 37.9 min at 50 degree C to 1.1 min at 57.5 degree C (z = 8.7 degree C). Cooking ground beef patties inoculated with B. anthracis on a gas grill to an internal temperature of 71.1 degree C resulted in pathogen reduction from 5.7 to 2.9 log10 CFU/g.  This study provided an understanding on how such threat agents behave in beef when intentional contamination could cause widespread human exposure.  Predictive models allow risk managers to estimate the probability of human exposure to these pathogens following the ingestion of potentially contaminated ground beef. This research supports the CRIS Project Plan by enhancing information provided by predictive models that are used in food safety management.

1935-42000-057-11S:  This report serves to document research conducted under a Specific Cooperative Agreement between ARS and the University of Tennessee.  There are not data that demonstrate the prevailing levels of lactate, acetate, or diacetate in retail RTE deli meat and their correlation to the occurrence of L. monocytogenes in these products.  Researchers at the University of Tennessee and the ARS Eastern Regional Research Center in Wyndmoor, PA quantify the levels of acetate, lactate, and diacetate occurring in retail RTE processed deli meat and poultry products previously analyzed for L. monocytogenes to determine the impact of current antimicrobial lethality treatments on occurrence of L. monocytogenes at retail.  The research product support the project plan and will provide data needed by the Food Safety and Inspection Service (FSIS) on the uniformity and levels of organic acids occurring in RTE processed meat and poultry products following implementation of the Listeria Rule in late 2003. 
1935-42000-057-12S:  This report serves to document research conducted under a Specific Cooperative agreement between ARS and the Michigan State University.  MSU conducted the Listeria transfer using mechanical slicer and RTE deli meat with consideration of different knives, product compositions (e.g. fat content), and etc.  MSU proposed to develop the transfer model using an experimental design.  The most significant accomplishments to date include: (1) acquisition of four model 2612 Hobart slicers, (including three types of blades) as well as one Berkel slicer (donated by Berkel) that was recently re-designed for enhanced cleanability; (2) the set up the three Hobart slicers and the Berkel slicer at a local delicatessen for one year of use and monthly sampling; (3) identification of the product contact areas on the slicers for sampling; (4) optimization of the blade inoculation method using surface-inoculated ham; and (5) collection of initial data on the potential and extent for sequential transfer of L. monocytogenes from the slicer blade to ham and other areas of the slicer during slicing.   We have contributed the measurement of the blade surface profiling of brand new blades and delivered the blades to MSU.   All the blades will be re-profiled after one year use.  The blade surface character is one of the key parameters to be used by MSU for model development.  
1935-42000-057-13S:  This report serves to document research conducted under a Specific Cooperative agreement between ARS and Rutgers University.  Predictive models allow food safety managers to forecast the fate of pathogens in food processing operations, however many small and very small processors require additional support in the use and interpretation of models. Rutgers University in New Brunswick, NJ and the ARS Eastern Regional Research Center in Wyndmoor, PA are developing a Predictive Microbiology Information Portal that provides on-line models, research data and background information for food safety applications. This research supports the  Project Plan by enhancing the transfer of predictive microbiology technology to food companies for use in food safety management.
1935-42000-057-14S:  This report serves to document research conducted under a Specific Cooperative agreement between ARS and University of Wisconsin. Understanding the risk of foodborne pathogens includes knowing conditions that cause the expression of virulence factors in food. Researchers at the University of Wisconsin in Madison, WI and the ARS Eastern Regional Research Center in Wyndmoor, PA are developing "reporter" strains of pathogenic E. coli O157:H7 that can be used to measure the expression of virulence factors under real food handling conditions. This research supports the Project Plan by enhancing information provided by predictive models that are used in food safety management.
1935-42000-057-15N:  This report serves to document research conducted under a Non-Funded Cooperative agreement between ARS and Technical Research Centre of Finland.  The Listeria transfer data between a slicer and gravad salmon were collected in the ERRC Lab, Microbial Food Safety Research Unit located at Wyndmoor, PA.  The experimental data involved different operation temperature, inoculum levels, cross-contamination steps and etc.   The studies showed that "empirical" model(s) for Listeria cross-contamination transfer prediction can be developed and applied to operations (with similar conditions).  The model(s) may be affected by many other operation conditions and/or physical properties of salmon, therefore, further studies will be needed. 
1935-42000-057-16G: This report serves to document research conducted under a General Assistance type of agreement between ARS and the AS Institute Food Science and Technology.  Professional activities funding was used to attend and to support the International Conference on Microbial Risk Assessment: Foodborne Hazards held in Sydney, Australia, on February 21-23, 2006.  This meeting provided a forum for risk analysts and food safety researchers to discuss the implementation of microbial risk assessment. High priority research objectives for further study that will appreciably aid regulators in drafting science-based policies and aid the industry on enhancing the wholesomeness of foods were identified.  Factors that have impeded the implementation of risk assessment and the strategies for accelerating their use in establishing Acceptable Levels of Protection, Food Safety Objectives and Performance Objectives against foodborne hazards were discussed. The products of this conference support the CRIS Project by aiding scientists in more effectively interfacing with food industry in adopting and implementing food processing performance criteria that control microbial hazards. 

**5.Describe the major accomplishments to date and their predicted or actual impact.**													This project recently completed the NP 108 OSQR Review Process and was certified.  See the report for 1935-42000-050-00D.

**6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)?  What are the constraints, if known, to the adoption and durability of the technology products?**													This project recently completed the NP 108 OSQR Review Process and was certified.  See the report for 1935-42000-050-00D.						
**7.List your most important publications in the popular press and presentations to organizations and articles written about your work.  (NOTE:  List your peer reviewed publications below).**													This project recently completed the NP 108 OSQR Review Process and was certified.  See the report for 1935-42000-050-00D.						
    Project TeamJuneja, Vijay Hwang, Cheng-An  - *Andy*Sheen, Shiowshuh Oscar, Thomas Bhaduri, Saumya  
Project Annual Reports FY 2009 FY 2008 FY 2007 FY 2006 Publications  Publications 
Related National Programs Food Safety, (animal and plant products)(108)  							Last Modified: 03/24/2010 		ARS Home |USDA.gov |Site Map |Policies and Links FOIA |Accessibility Statement |Privacy Policy |Nondiscrimination Statement |Information Quality |USA.gov |White House

**