Progress 06/01/24 to 05/31/25
Outputs
Target Audience:For the reporting period, the primarytarget audience for research activities were/are members of the U.S. processed, value-added meat industries and aligned food safety validation stakeholders. Research completed focused on the manufacture of pathogen-controlled/free, validated fermented, dried meats, wherein the targeted human microbial pathogens of concern includeSalmonella enterica, Shiga toxin-producingE. coli(STEC), andListeria monocytogenes. Commercial manufacturers of fermented, dried salami-style products (and like meat products) are expected to benefit directly from enhanced predictive modeling approaches incorporating machine learning approach(es) to validate effective pathogen control for purposes of foodborne disease risk reduction. Aligned with this are members of the food safety protection industries, as well as USDA-FSIS and state regulatory agencies with responsibilities over ensuring meat products safety for value-added, cured, fermented and dried meat products. Changes/Problems:Investigator Osburn encountered an unexpected change in corporate leadership of previously identified meat and non-meat ingredient key supplier, based in Bryan, TX, adjacent to lead institution. This change in leadership resulted in the commercial firm's being unable to reliably source lean and fatty meat trim, as well as non-meat ingredients, in a timely fashion to support research. Dr. Osburn responded by identifying new suppliers of meat and non-meat ingredients, but nonetheless this need to identify new suppliers resulted in an approximately four-month delay to inoculated salami experiments at TAMU under Dr. Taylor's leadership. Previously identified commercial starter cultures produced by one U.S. based food products and ingredients company were discontinued for retail sale by the commercial firm, prompting investigators Taylor and Osburn to identify new sources of starter cultures to initiate and progress through inoculated pathogen reduction-focused experiments. This work was completed concurrent to identification of new meat and non-meat ingredient suppliers, not costing researchers significant additional time, but did result in experimentation between investigators Taylor and Bergholz to differ in starter cultures evaluated. Dr. Taylor's lab evaluated three starters produced by the firm Chris Hansen, whereas previously Dr. Bergholz had used a starter culture by the U.S. firm Kerry. Kerry discontinued its sale of the starter, and now all future work will be completed using starters produced by Chris Hansen for both labs. What opportunities for training and professional development has the project provided?The project has supported the training of one Ph.D.-degree student at Texas A&M University and has also engaged one undergraduate student assistant who provided microbiological analysis assistance to the PhD. Student during data collection/microbiological experiments. The undergraduate's assistance provided additional food microbiology skills to the undergraduate she will use as she initiates a graduate degree program in a food fermentation laboratory at Texas A&M. The project has also recruited aligned research assistance from a M.S. student in the Department of Animal Science at Texas A&M who provided quantitative gene expression assistance to the project-supported PhD student and gained more experience on gene expression in prokaryotic microbes. This has helped them further their understanding of differential gene expression and assisted a new collaboration between investigator Taylor and epigenetics researcher at TAMU. The project also recruited assistance from a post-doctoral associate in Dr. Taylor's laboratory, not funded by the project, to aid the PhD student in experimental design and skills development for foods microbiological analysis. The project facilitated the recruitment of a summer research intern student, an undergraduate student from St. Edward's University (Austin, TX), to come and complete aligned research to the project intended to test the utility of Salmonella bacteriophages to reduce Salmonella in a meat-simulated broth system alongside fermentative starter cultures. The student's summer research internship was planned as a hypothesis-driven research experiment to determine whether phages might benefit salami safety without compromising fermentation of acids from supplied sugar. The project has supported the training of one Ph.D.-degree student at Michigan State University. The project has also supported the training of one M.S. degree-seeking student at the University of Tennessee-Knoxville. How have the results been disseminated to communities of interest?Results of research efforts during the reporting period were disseminated to attendees at the 2025 3-A Institute's Summit on Hygienic Design, held in the Spring 2025 in Chicago, IL. A PhD student being trained on this project presented findings from her research. Additionally, another presentation of research outcomes was given at the International Association for Food Protection Annual Meeting in July 2025 by another PhD student trained on/supported by this project, in Cleveland, OH. Finally, co-PI investigator Osburn communicated findings from salami formulation quality control analysis and aligned researches at the American Meat Science Association Reciprocal Meat Conference in 2025, though a presentation specifically funded by this project was not delivered. What do you plan to do during the next reporting period to accomplish the goals?Investigator Taylor and Bergholz anticipate completion of identification of "worst case" commercial starter culture product to facilitate completion of initial model parameterization (Obj. 1), thereby accelerating the progression of Objective 2 research along with investigator Chen to develop a comprehensive mathematical model that may be tested and subjected to preliminary validation for pathogen control during commercial manufacture. They also expect to apply a set of previously identified generic E. coli as candidate surrogates for later (Obj. 3) use in a commercial validation with a cooperating small meat products manufacturer in Texas. The generic E. coli are suspected to behave similarly to pathogens and will be compared via inactivation kinetics analysis to the data and predictions yielded by the model produced by Dr. Chen to determine their fitness as pathogen surrogates. All investigators will also collaborate to identify other possible means of model testing and validation, with Dr. Chen giving leadership to the assembly of methods for model testing and validation. Investigators Taylor and Osburn will quantify pathogens reduction (Salmonella, STEC) on salamis during fermentation+drying, using the previously identified "worst" commercial starter, delivering microbiological and physico-chemical data to investigators Chen and Bergholz on pathogen survival over fermentation and drying in the core, outer ridge and on the exterior surface of cased salamis. These data will be gathered on salamis cased at 32 mm collagen casings. These will complement Investigator Chen's existing models to provide kinetic indices of pathogen reductions during salami manufacture, and give differentiation from pathogen reductions in smaller (19 mm) cased salamis. Another major objective to complete will be the identification and assessment of pathogen surrogates for comparison to model parameters, validating the utility of identified surrogates as accurately reflecting modeled pathogen behaviors during salami manufacture. Investigators Taylor and Bergholz collaboratively propose the use of generic E. colipreviously studied and published as useful surrogates for similar meat animal carcass decontamination and fermentation safety validations, and these will be the first set of microbes used in comparison to model designs supplied by investigator Chen. Investigator Osburn will oversee salami formulation standardization and supply chain design to facilitate microbiological testing by investigators Taylor and Bergholz, ensuring product formulation consistency across the two labs. Initial contacts and plans with project-supporting commercial Small meats manufacturer will be made and meetings completed to outline needed timelines, safety considerations and expectations from research, and data gathering expected.
Impacts
What was accomplished under these goals?
Under objective 1, investigators Taylor and Osburn cooperated to prepare several salami batters inoculated with cocktails of USDA-FSIS-supplied Salmonella enterica isolates (7 isolates) collected from inspected establishments harvesting beef or manufacturing further processed and RTE meats, and 7 isolates comprising the O157 and non-O157 Big Six STEC (supplied by USDA-ARS), and inoculated with one of three commercially supplied lactic acid bacteria (LAB) starter culture products. The starter culture products were Flora ItaliaLC (Chris Hansen), Bactoferm LHP (Chris Hansen), and Bactoferm HPS (Chris Hansen), all selected as useful for manufacturing salami-style products. All starter cultures were purchased by project investigators. Salami batters were prepared with 1.0% dextrose as a fermentable carbohydrate and were inoculated to a target of 7.0 log CFU/g Salmonella and 7.0 log CFU/g STEC. Following blending and stuffing into a 32 mm cellulose-type casing, links were clipped and hung in a controlled environment chamber in the Food Microbiology Laboratory useful for completion of simulating commercial fermentation and drying. The Bergholz Lab completed laboratory-scale salami fermentations to compare Listeria monocytogenes reduction across three commercial starter cultures (LHP, F-LC, Saga 200) under controlled fermentation and drying conditions. The objective was to identify the culture and process parameters producing the slowest acidification and lowest L. monocytogenes inhibition--representing the most challenging scenario for pathogen control. The fermentation environment was optimized by implementing real-time monitoring of core and surface sausage temperatures, sausage pH, and fermenter temperature and relative humidity. These measurements were collected to inform predictive modeling and to determine the optimal number and timing of sampling points for future work. Reduction kinetics were modeled using the Gompertz equation to estimate total reduction, rate of reduction, and time to maximum reduction. Under objective 2, investigator Chen focused on modeling development to simulate the fermentation and drying of sausage/salami. First, using the experimental data collected by investigators Taylor, Osburn, and Bergholz, a pH-dependent inactivation kinetics modeling concept was developed to estimate the pH-dependent D- and z-values. This kinetic model is under refinement to be integrated with the comprehensive modeling of the entire sausage/salami processing, including fermentation and drying. Second, investigator Chen developed a modeling framework to simulate the sausage/salami drying process. This drying model will be updated using the parameters determined from the experimental results later.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2025
Citation:
Nam, J.H., T.M. Taylor, and T.M. Bergholz. 2025. Impact of starter cultures on Listeria monocytogenes reduction dynamics in salami. International Association for Food Protection Annual Meeting, Cleveland, OH.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2025
Citation:
Ajayi, B.E., A. Parry-Hanson Kunadu, W.N. Osburn, T.M. Taylor. 2025. Validation of a process criteria model for controlling Salmonella enterica and Shiga-toxigenic Escherichia coli in fermented dried sausage. 3-A Sanitary Standards Institute 2025 Summit on Hygienic Design, Chicago, IL.
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Progress 06/01/23 to 05/31/24
Outputs
Target Audience:At Texas A&M, two differing presentations over findings to date were disseminated to members of the College of Agriculture and Life Sciences, as well as across the university (College Station, TX) by the project-supporting student B.E. Ajayi (Animal Science). These presentations allowed the student to gain experience at presenting research data on the topic of the research to agriculture/food-focused and non-focused campus members. These presentations contacted primarily sausage consumers as stakeholders and other scientific researchers in the biological, agricultural, and engineering sciences. In 2023, concurrent with the USDA-NIFA's Investigators' Annual meeting in Toronto, Canada, Co-PI T. Bergholz presented the initial planned project to other attendees, alerting other USDA-funded food safety and defense-contracting researchers to the team's planned work. Dr. Bergholz presented a collaboratively developed project poster and answered questions of USDA and others related to intended research. This presentation contacted USDA-NIFA employees as well as other food safety professionals in government and academia primarily. This relayed the core objectives of the research, the team's logic model for approaching the researchable question(s), and the approach. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Co-PDs Taylor and Chen met at the 3rd Annual Artificial Intelligence in Agriculture research meeting. Held on the campus of Texas A&M University in April 2024, the third annual Artificial Intelligence in Agriculture conference brought researchers from across the U.S. to Texas A&M to discuss current applications, opportunities, limitations and concerns of AI and machine learning in agricultural production and post-harvest systems. Drs. Chen and Taylor used the meeting as an opportunity to meet with graduate student working on the project, identify possible collaborators to leverage the project into additional research options, and identify next generation grant opportunities for continuing research. Additionally, Drs.Taylor and Chen met with possible research collaborators independently to continue the lines of food safety focused research. Identified line of research for grant development centers on developing modeling approaches to validate safety of stabilized meat products, including large sausage and uncured meats against Clostridium safety hazards by using non-sporeforming surrogate microbes and reactive enzymes. This can leverage this grant into continuing the development of enhanced food safety validation tools for the processed meats industry, helping to secure the future of fully cooked meats manufacture and sale, by reducing the risk of product safety loss, recall, andunavailability to consumers. Drs. Bergholz and Osburn have leveraged the granted project to facilitate training of recruited graduate assistants towards data collection. Dr. Bergholz has been working to complete FSIS-supported CRADA-type research and her lab has assisted in getting data onListeriainitiated for this project. Dr. Osburn has helped Dr. Taylor's group collect preliminary data by allowing his students funded on other aligned projects to assist Dr. Taylor's group by gathering pH and water activity data along with other data, giving Dr. Taylor's recruited graduate assistant added understanding of quality control measures for pH and chemical data gathering from a meat product. The project has allowed the recruitment of a graduate assistant with no functional food/meat science training. The assistantship has allowed the student (B.E. Ajayi) with opportunity to complement previous academic training in microbiology with formal instruction in value-added meats processing and food science/food formulation. How have the results been disseminated to communities of interest?As discussed, results to date have been reported both locally on the TAMU campus as well as nationally through volunteered presentations (see Products citations). These presentations provided opportunity for graduate assistants to gain experience at presentation of research methods and data to non-meat/food safety specialists, as well as to meat processing and safety specialists. Communications of PDs with USDA-FSIS personnel, purposed with obtainingSalmonellaisolates, have also facilitated the relay of preliminary findings and research updates from collaborators/investigators to FSIS personnel. What do you plan to do during the next reporting period to accomplish the goals?Initiation and completion of pathogen-inoculated fermentation and drying monitoring experiments are expected for year 2, completing phases of studies linked to Objective 1 and the first major component of Obj. 2, formulating the predictive model. These experiments will link microbiological with physico-chemical and other data streams, resulting in the multi-variate model put together by Dr. Chen. Researcher Taylorisexploring alternative funds sources to leverage the grant-funded research by preparingSalmonella-inoculated samples that also incorporate USDA-approved phages as an added antimicrobial technology to help achieve a 5.0 log-cycle reduction in the pathogen during fermentation and drying without negatively impacting the metabolic activity of starter cultures. If successful, this would add to the validation of safety of sausages against FSIS standards for minimum pathogen reduction and open a line of research not already ongoing to the researchers awareness. Dr. Osburn will assist researchers in verifying the correct formulation of the salami batter and its stuffing/preparation for inoculated experiments involving sausage fermentation and drying. He will give Dr. Taylor's student added training as needed to help ensure cross-training across meat preparations. Co-PD Chen will receive data towards model design and initial validation work. Co-PDs Taylor and Bergholz will feed data through shared data folders stored in TAMU OneDrive, and through literature reviews with recruited graduate assistants assist Chen in iterative model testing and parameterizations.
Impacts
What was accomplished under these goals?
Project Data Generation:PDTaylor initiated recruited graduate student training with collaborative input from Co-PDBergholz to facilitate assembling and activating a collection of O157 and non-O157STEC provided isolates from USDA-ARS personnel. Additionally, as indicated elsewhere in this report, Co-PDBergholz assisted with identifying USDA contacts to provide 10 Salmonella isolates from 9 differing serovars collected from meat manufacturing establishments. USDA personnel were contacted and needed MTA processes completed in order to obtain the organisms from USDA-ARS with FSIS assistance. Following organisms' receipt, the student research assistant was trained and initiatedpreliminary testing to verify the growth kinetics of Salmonella organisms in the medium tryptic soy broth. STEC isolates growth characteristics were known from previously completed/already published research. The growth assay was designed to allow researchers to identify minimum reliable time at 37 C for Salmonella to enter mid-stationary phase, anticipated to provide the greatest degree of tolerance to lactic acid and dehydration processes characteristic of the manufacture of these products. Experimental data from these growth trials demonstrated 14 hr. minimum growth in nutritious medium was required for Salmonella and STEC isolates to achieve 9.0 log-cycles or greater consistently. Dr. Bergholz's group confirmed similar findings in their laboratory andalso demonstrated previously gathered data detailing pH, water activity, and pathogen reductions occurring in similarly formulated salami-style sausages. Dr. Bergholz has reported data to the group from other funded research demonstrating a consistently difficulty in achieving significant declines in Salmonella in smaller diameter sausages versus larger diameter products, potentially the result of moisture migration pattern differences, but is not suspected to be a function of pH differences. We anticipate exploring this more in depth as FSIS personnel have confirmed similar observations anecdotally and it warrants further evaluation. Dr. Bergholz's group has, along with Dr. Taylor's group, initiated the supply of quantitative data to Dr. Chen to initiate the design of a complex predictive model to begin the procedure of developing a primary validation model. Growth kinetic data from Salmonella growth have been supplied to aid model design. Co-PD Chen was supplied data from PD Bergholz to initiate the development of the initial model as well as by PD Taylor, giving parameters ofSalmonellaand STEC growth. In collaboration, Drs. Bergholz and Taylor have initiated experiments to compare quantitatively the counts ofSalmonella,L. monocytogenesand STEC isolates inoculated into a standard salami batter formula (provided and verified by Co-PD Osburn) to track the fermentation of acid from dextrose from each of three differing commercial starter culture products (one powder, one liquid, one frozen concentrate). These experiments will be completed for sausages filled into 19 and 32 mm casings (collagen) to determine if diameter impacts fermentation onset and kinetics. From these samples, pathogen counts forSalmonellawill be compared both by plating and via qPCR (BAX Hygiena) to compare and initiate understanding of whether qPCR can effectively substitute for plate counts. Additionally, researchers will track Ct values forLm-inoculated sausages to quantitate the parameters of PCR-based pathogen detection and relate to counts of pathogen cells, leveraging research funding to add new data to the intended model and improve its industrial usefulness. Co-PD Osburn has led his group in identifying a useful batter and has verified capability to formulate and produce a baseline salami product, as well as experimentally designed a commercial environmental chamber to be able to hold experimental sausage links with wireless data loggers for product temperature and environmental humidity and windspeed. Probes have been identified and obtained allowing for surface temperature and core temperature monitoring, as well as pH and water activity probes for physico-chemical data gathering incrementally. These plans and activities have assisted in researchers nearly completing research studies linked to Objective 1, producing data that are being fed to Co-PD Chen to initiate Objective 2. Team Meetings:A team meeting was held in late August 2023 wherein initial plans were formulated and project-recruited student(s) were introduced to Co-PIs, via Zoom. The project timeline was reviewed for the initial phase of the project, and discussions were held on the topics of starter cultures selection for "worst-case" scenario replication. PIs Bergholz and Taylor agreed to and successfully recruit a selection of Salmonella enterica isolates from the USDA-FSIS that were previously collected from commercial fermented meat and processed meat manufacturing environments. Dr. Bergholz leveraged ongoing research and networks to identify useful USDA points of contact to facilitate the initial outreach leading to investigators' collection of isolates. A second meeting was completed May 2024, wrapping the Spring academic term's completion of research on aligned projects and outlining research goals for the Summer 2024 term and into the Fall term, initiating Year 2 of the project. Data Management Plan Accomplish: Texas A&M Agrilife's use of Microsoft's OneDrive/Sharepoint system is leveraged to create a shared data storing location, allowing research data to be deposited for storage and access by project research personnel. This forms a centralized repository in addition to investigators' respective personal data storage mechanisms/satellite storage forms/sites.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Taylor, M., W. Osburn, J. Chen, and T.M. Bergholz. 2023. Validation of microbial pathogen control on dried RTE sausages by novel antimicrobial and mathematical approaches. 2023 U.S. Department of Agriculture - National Institute for Food and Agriculture Investigators Annual Meeting, Toronto, Ontario, Canada.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2024
Citation:
Ajayi, B.E., W.N. Osburn, and T.M. Taylor. 2024. Validation of Salmonella and STEC control in uncooked fermented sausage products. 2024 Texas A&M University Student Research Week, College Station, TX.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2024
Citation:
Ajayi, B.E., W.N. Osburn, and T.M. Taylor. 2024. Validation of Salmonella and STEC control in uncooked fermented sausage products. Texas A&M University - College of Agriculture and Life Sciences Mini Research Symposium, College Station, TX.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Harrison, A., A.L. Shimwa, N. Broz, K. Zwally, W. Osburn, A. Pollock, and T.M. Taylor. 2023. Comparing Salmonella enterica to two non-pathogenic surrogates in an uncooked, fermented, and dried sausage process. American Meat Science Association 2023 Reciprocal Meat Conference, Minneapolis, MN.
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