Progress 03/02/16 to 02/28/21
Outputs
Target Audience:Our key stakeholders for this project are: (1) Suppliers of pasteurization equipment for the low-moisture food and meat/poultry industries, (2) Ingredient suppliers, (3) Processors utilizing or producing ready-to-eat low-moisture and/or meat and poultry food products, and (4) The U.S. Food & Drug Administration and the U.S. Department of Agriculture - Food Safety Inspection service (as the relevant regulatory agencies). Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The entire research team (including all undergraduates and graduate students) has been trained in advanced laboratory techniques necessary for conducting experiments with biosafety level-2 pathogens in low-moisture powders, which present specific challenges in ensuring worker safety, due to risk of airborne particles during sample preparation and handling. Additionally, 8 members of the project team attended the annual meeting of the International Association for Food Protection, where they presented project results and participated in various Professional Development Groups. How have the results been disseminated to communities of interest?Project results have been shared with key stakeholders via presentations at scientific conferences and through peer-reviewed journals. Additionally, key project results have been shared directly with industry groups (e.g., the North American Millers Association and the North American Meat Institute) and regulatory stakeholders (e.g., the USDA Food Safety Inspection Service). What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The overall project entailed four types of activities: (1) lab-scale studies generating microbial response data for the multiple pathogens, products, and processes, (2) development of mathematical models to describe bacteria inactivation and/or transfer, (3) pilot-scale studies to validate those models, and (4) utilization of the models to develop and deploy tools and training directly applicable to commercial applications. By working directly at the interface of food microbiology and engineering, this project generated unique contributions toward improving the safety of ready-to-eat products, primarily by improving the ability of food processors and food safety regulators to reliably evaluate and validate the efficacy of pathogen reduction processes. A few example accomplishments from the past year are highlighted below, with significant emphasis in the past year being on Overall Goal 2, Objective 2. First, we conducted a novel battery of Salmonella- and surrogate-inoculated challenge studies for impingement cooking of bacon to evaluate process sufficiency. Unlike other ready-to-eat (RTE) meats, bacon cooking is primarily controlled based on final product yield. However, there is very limited information supporting pathogen lethality in commercial fully-cooked bacon. Commercially produced traditional and thick-cut bacon slices were inoculated with Enterococcus faecium NRRL B-2354 (a non-pathogenic surrogate) or an 8-serovar cocktail of Salmonella. Inoculated samples were cooked in a pilot-scale moist-air impingement oven at multiple humidities, temperatures, and durations to a commercially-relevant yield (40%). All treatments achieving the target product yield achieved >6.5 log reductions of Salmonella. Additionally, all products that were cooked below the target yield (average 75%) also achieved >6.5 log reductions of Salmonella and E. faecium. Fully and partially-cooked bacon achieved average maximum surface temperatures of 121± 7.8 and 92 ± 1.0ºC, respectively. Experimental results indicate that typical commercial cooking practices for fully-cooked bacon ensure that the target 6.5 log reduction of Salmonella lethality is ensured. This scientific evidence is important in meeting a need for processors to comply with USDA FSIS regulations. Under the same objective, we evaluated the efficacy of practical, supplemental critical controls on Salmonella lethality during other impingement cooked meat products (e.g., beef patties and whole-muscle beef strips, cooked under multiple process temperatures and humidities. Five critical controls were evaluated, including adhering to minimum USDA FSIS Appendix A guidelines and pre-/post-process controls (increased endpoint temperature, post-oven carryover time, and pre- or post-oven steam treatments). The efficacy of minimal and supplemental critical controls were product- and process-humidity-dependent (P < 0.05). Higher Salmonella reductions were observed with added process humidity and in beef strips (P < 0.05). No single supplemental control resulted in universal assurance of Salmonella reductions; most supplemental treatments were not significantly better than minimal critical control treatments (P > 0.05). No treatment reliably ensured >6.5 log reductions of Salmonella in ground beef.? The effectiveness of time, temperature, and humidity controls were highly variable and dependent on product batch. While compliance with current USDA FSIS Appendix A guidelines is critical for the meat industry to provide a safe product, revisions are needed to reflect the importance of process humidity and product variability in order to ensure food safety. In the area of low-moisture foods, we evaluated the efficacy of multiple published home-scale thermal interventions for pasteurizing multiple flours. All-purpose, whole-wheat, and gluten-free (rice-based) varieties of flour were inoculated with Salmonella Enteritidis PT 30 (~8.65 log CFU/g), and conditioned to a water activity of ~0.45. Samples (three replications with triplicate 4-8 g subsamples) were spread into a uniform layer ~ 0.5 cm thick, heat-treated in a convection oven at 177°C up to 10 min. In all-purpose, whole wheat, and gluten free flours, these treatments resulted in log reductions (mean ± standard deviation) of 3.28 ± 0.52, 4.09 ± 0.46, and 4.13 ± 0.67, respectively. There were significantly less Salmonella reductions in all-purpose than in whole-wheat and gluten-free flour. Samples did not achieve greater than an average 5 log reduction after a 10 min treatment (P < 0.05). Awareness of microbial hazards associated with low-moisture products is increasing; however, none of the home-scale solutions evaluated were scientifically supported. While treated flour resulted in less Salmonella, it is currently unknown whether this is a sufficient or best practice for consumers. Overall, the results from this cumulative project have continued to support the premise that microbial inactivation models are valuable tools for validating pathogen control processes, but that there remain critical gaps in fully describing the impact of key product/process factors on process outcomes. Therefore, it is extremely important to use product-specific inactivation parameters, and appropriate statistical approaches, as developed in this project, when validating pathogen control processes.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Casulli KE, Dolan KD, Marks BP. 2021. Modeling the effects of product temperature, product moisture, and process humidity on thermal inactivation of Salmonella in pistachios during hot-air heating. J. Food Prot. 84:47-57.
|
Progress 10/01/19 to 09/30/20
Outputs
Target Audience:Our current key stakeholders for this project are: (1) Suppliers of pasteurization equipment for the low-moisture food and meat/poultry industries, (2) Ingredient suppliers, (3) Processors utilizing or producing ready-to-eat low-moisture and/or meat and poultry food products, and (4) The U.S. Food & Drug Administration and the U.S. Department of Agriculture - Food Safety Inspection service (as the relevant regulatory agencies). Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The entire research team (including all undergraduates and graduate students) has been trained in advanced laboratory techniques necessary for conducting experiments with biosafety level-2 pathogens in low-moisture powders, which present specific challenges in ensuring worker safety, due to risk of airborne particles during sample preparation and handling. Additionally, 8 members of the project team attended the annual meeting of the International Association for Food Protection, where they presented project results and participated in various Professional Development Groups. How have the results been disseminated to communities of interest?Project results have been shared with key stakeholders via presentations at scientific conferences and through peer-reviewed journals. Additionally, key project results have been shared directly with industry groups (e.g., the North American Millers Association and the North American Meat Institute) and regulatory stakeholders (e.g., the USDA Food Safety Inspection Service). What do you plan to do during the next reporting period to accomplish the goals?Overall, during the next reporting period, the project will focus on the following activities: (1) Continuing to test novel approaches to modeling the product-process effects on thermal inactivation of Salmonella on/in low-moisture products and on the surface of meat/poultry products, (2) A significant meta-analysis of the statistical power of experimental approaches to commercial process validations in the low-moisture food industry (a collaboration with the almond industry), and (3) Additional pathogen-inoculated, pilot-scale validation trials with meat/poultry products, aimed at evaluating experimental and modeling-based approaches to validating pathogen control.
Impacts
What was accomplished under these goals?
The overall project entails four types of activities: (1) lab-scale studies generating microbial response data for the multiple pathogens, products, and processes, (2) development of mathematical models to describe bacteria inactivation and/or transfer, (3) pilot-scale studies to validate those models, and (4) utilization of the models to develop and deploy tools and training directly applicable to commercial applications. By working directly at the interface of food microbiology and engineering, this project is generating unique contributions toward improving the safety of ready-to-eat products, primarily by improving the ability of food processors and food safety regulators to reliably evaluate and validate the efficacy of pathogen reduction processes. A few example accomplishments from the past year are highlighted below. Under Overall Goal 1, we completed a study to assess and model the effects of process temperature, process humidity, air velocity, and product moisture content on Salmonella inactivation on whole almonds. Whole almonds were inoculated with Salmonella Enteritidis PT30, equilibrated at controlled relative humidity, and then heat treated with air at multiple process humidities and air velocities. Process temperature and humidity were significant factors, and distinct parameters were obtained for each model. The model results demonstrated that air velocity affected microbial inactivation, independent of the time-temperature effect. Analysis of residuals indicated there also was an effect of product moisture content, for which the best model form remains inconclusive. Overall, the results suggest that air velocity impacts Salmonella thermal resistance in thermal inactivation processes, independently of temperature effects, likely reflecting velocity effects on the relative influence of process humidity vs. product moisture. This was the first study to isolate and demonstrate this velocity effect, which will be important in developing the most appropriate models for thermal process validations. Contributing to Overall Goals 1, 2, and 3, our team completed the first major, systematic evaluation of process humidity effects on Salmonella lethality at both the core and surface of impingement-cooked RTE products, via inoculated, pilot-scale cooking trials in the MSU Biosafety Level-2 Pilot Plant. This study demonstrated the following groundbreaking results: (1) The minimum time-temperature combinations published in the current regulatory guidelines do not achieve the targeted level of pathogen lethality in dry ovens; (2) Even at higher humidity conditions, the minimum time-temperature combinations published in the current regulations do not reliably yield the target level of safety for all meat and poultry products; and (3) In dry ovens, greater Salmonella lethality can be achieved at the product core (cold spot) than on the product surface (hot spot), due to desiccation significantly increasing Salmonella thermal resistance at the product surface. These results have been presented to the industry and scientific peers via five invited talks at multiple national conferences. These results also were presented directly to the staff of the USDA FSIS Office of Policy and Program Development (OPPD), who are using the results as part of their pending revision of the guidelines for pathogen control in RTE products (known as "Appendix A"). Our pending publication of this work will be a critical piece of scientific evidence affecting how the FSIS modifies the humidity requirements. Overall, the results from this past year have continued to support the premise that microbial inactivation models are valuable tools for validating pathogen control processes, but that there remain critical gaps in fully describing the impact of key product/process factors on process outcomes. Therefore, it is extremely important to use product-specific inactivation parameters, and appropriate statistical approaches, as developed in this project, when validating pathogen control processes.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Hildebrandt IM, Marks BP, Anderson NM, Grasso-Kelley EM. 2020. Reproducibility of Salmonella thermal resistance measurements via multi-laboratory isothermal inactivation experiments. J. Food Prot. 83:609-614.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Gomez CB, Marks BP. 2020. Monetizing the impact of food safety recalls on the low-moisture food industry. J. Food Prot. 83:829-835.
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Moussavi M, Frelka JC, Hildebrandt IM, Marks BP, Harris LJ. 2020. Thermal resistance of foodborne pathogens and Enterococcus faecium NRRL B-2354 on inoculated pistachios. J. Food Prot. 83:1125-1136.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2020
Citation:
Maz�n Villegas B, Hall NO, Ryser ET, Marks BP. 2020. Influence of physical variables on the transfer of Salmonella Typhimurium LT2 between potato (Solanum tuberosum) and stainless steel via static and dynamic contact. Food Microbiology. 20: In press.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2020
Citation:
Suehr QJ, Marks BP, Ryser ET, Jeong S. 2020. Modeling the propagation of Salmonella within bulk almond using discrete element method particle simulation technique. Journal of Food Engineering. In press.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2020
Citation:
Klug I, Hildebrandt I, James M, Marks B. 2020. Evaluating a Salmonella lethality prediction tool for the surface of cooked meat and poultry products. Abstract P1-151. Presented at the Annual Meeting of the International Association for Food Protection. Oct 26-28, 2020.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2020
Citation:
Hildebrandt I, Hall N, James M, Marks B. 2020. Impact of supplemental critical controls on Salmonella reductions in ready-to-eat beef products. Abstract P1-155. Presented at the Annual Meeting of the International Association for Food Protection. Oct 26-28, 2020.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2020
Citation:
Randriamiarintsoa N, Hildebrandt I, James M, Hall N, Marks B. 2020. Salmonella lethality in fully-cooked bacon and evaluation of a non-pathogenic surrogate Enterococcus faecium for validation purposes. Abstract P1-167. Presented at the Annual Meeting of the International Association for Food Protection. Oct 26-28, 2020.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2020
Citation:
Kearney A, Hildebrandt I, James M, Hall N, Marks B. 2020. Quantifying the survival of Salmonella during the long-term storage of multiple sugar products. Presented at the Annual Meeting of the International Association for Food Protection. Oct 26-28, 2020.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2020
Citation:
Ahmad N, Marks B, Ryser E. 2020. Effect of sugar composition on resuscitation of Salmonella and Enterococcus faecium NRRL B-2354 survivors in heat-treated skim milk powder and lactose-free skim milk powder. Abstract P2-127. Presented at the Annual Meeting of the International Association for Food Protection. Oct 26-28, 2020.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2020
Citation:
Suehr Q, Marks B, Jeong S. 2020. Integration of pathogen reduction models within computational fluid dynamics simulations of the spray drying process. Abstract P2-156. Presented at the Annual Meeting of the International Association for Food Protection. Oct 26-28, 2020.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2020
Citation:
Gomez C, Marks B, Ryser E. 2020. Kitchen-scale treatments for reduction of Listeria monocytogenes in prepared produce for immunocompromised populations. Abstract P3-138. Presented at the Annual Meeting of the International Association for Food Protection. Oct 26-28, 2020.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2020
Citation:
Gomez, Carly. 2020. The effects of kitchen-scale produce preparation techniques on the risk of listeriosis in cancer patients. M.S. Biosystems Engineering. Michigan State University. East Lansing, MI.
|
Progress 10/01/18 to 09/30/19
Outputs
Target Audience:Our current key stakeholders for this project are: (1) Suppliers of pasteurization equipment for the low-moisture food and meat/poultry industries, (2) Ingredient suppliers, (3) Processors utilizing or producing ready-to-eat low-moisture and/or meat and poultry food products, and (4) The U.S. Food and Drug Administration (as the relevant regulator). Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The entire research team (including all undergraduates and graduate students) has been trained in advanced laboratory techniques necessary for conducting experiments with biosafety level-2 pathogens in low-moisture powders, which present specific challenges in ensuring worker safety, due to risk of airborne particles during sample preparation and handling. Additionally, 6 members of the project team attended the annual meeting of the International Association for Food Protection, where they presented project results and participated in various Professional Development Groups. How have the results been disseminated to communities of interest?Project results have been shared with key stakeholders (beyond scientific conferences) by the following means in the past year: (1) Presentations at an industry conference - IFTPS 2019, (2) An on-site, 1.5-day workshop at the International Association for Food Protection Annual Meeting, and (3) a webinar distributed by the International Association for Food Protection in December 2019. What do you plan to do during the next reporting period to accomplish the goals?Overall, during the next reporting period, the project will focus on the following activities: (1) continuing to test novel approaches to modeling the product-process effects on thermal inactivation of Salmonella on/in low-moisture products, (2) conducting additional pilot-scale validation trials, particularly in the areas of baking and meat/poultry cooking (focused on humidity effects), and (3) Developing and testing modeling and statistical tools for process validations. Significant data sets are being acquired from collaborators, for Salmonella inactivation in baking and drying processes, and inactivation models incorporating process humidity and dynamic process moisture content will be tested against these diverse data sets. Based on those results, modeling tools currently in distribution and industry use are anticipated to be modified/improved. Secondly, additional pilot-scale challenge studies will be conducted, in which the effects of product properties and process conditions (e.g., humidity) on Salmonella inactivation will be tested in baking, cooking, and various drying processes. In addition to model accuracy, process variability and validation uncertainty will be quantified.
Impacts
What was accomplished under these goals?
The overall project entails four types of activities: (1) lab-scale studies generating microbial response data for the multiple pathogens, products, and processes, (2) development of mathematical models to describe bacteria inactivation and/or transfer, (3) pilot-scale studies to validate those models, and (4) utilization of the models to develop and deploy tools and training directly applicable to commercial applications. By working directly at the interface of food microbiology and engineering, this project is generating unique contributions toward improving the safety of ready-to-eat products, primarily by improving the ability of food processors and food safety regulators to reliably evaluate and validate the efficacy of pathogen reduction processes. A few example accomplishments from the past year are highlighted below. Under Overall Goal 1, this project has continued to generate multiple outputs on the complex relationships between product moisture content, water activity, surface temperature, and process humidity with Salmonella thermal resistance. In one example study, Salmonella-inoculated almonds were equilibrated to two moisture (%MC) levels but the same aw, and two aw levels but the same %MC, to test the separate effects of MC and aw. D80°C-values effects were not attributable to aw or %MC. Overall, our results demonstrate that it is critical to understand product moisture status when validating pasteurization technologies. Under Overall Goal 2, we completed an extremely novel economic analysis, in which we monetized the impact of food safety recalls on the low-moisture food industry. Financial impacts of recalls were analyzed by computing the Cumulative Abnormal Return (CAR) in stock values over a recall event period. The mean CAR for a 20-day post-recall period was -5%. This translated to a mean company loss of $460M for the recall events analyzed in this study. If implementation of a food safety technology could, as an illustration, reduce recall risk by less than one log, that would translate into a mean annual economic benefit of >$2.5M in reduced risk for companies like those in the study. Such analyses have potential to positively impact business decisions to invest in food safety technologies. Under Overall Goal 3, our pilot-scale challenge studies with low-moisture foods are now increasingly focused on formulated food products. As an example, we have completed several projects, at multiple sites, testing the effect of product and process conditions on baking as a pathogen control technology. In one study on baking of thin crackers, isothermal inactivation parameters for Salmonella were developed using the raw dough, and then applied to time-temperature curves from actual baking trials. The results clearly demonstrated that this validation method grossly overpredicted (P<0.001) actual lethality. Again, these results are significant, given that there are existing practices and recommendation in the industry that suggest this approach, which we have demonstrated can be fail-dangerous. We have also completed a comparable study evaluating the effects of process humidity on Salmonella lethality in meat and poultry products cooked in a pilot-scale impingement oven, which is critically relevant to a recent revision of the USDA FSIS Appendix A requirements for ready-to-eat products. The study included breaded chicken patties, whole-muscle chicken breast filets, whole-muscle beef strips, and ground-and formed beef patties, cooked under various process temperatures, humidities, and air velocities. The overall results demonstrated that: (1) Cooking product to the current regulatory-minimum endpoint center temperatures yielded the target pathogen lethality for some, but not all, of the conditions, (2) Dry oven conditions failed to reliably achieve the target lethalities, (3) Dry oven conditions resulted in greater (P<0.05) Salmonella lethality in the product core than at the surface, (4) Lethality was affected by humidity and air speed (P<0.05), and (5) Pre-oven steam and post-cook carryover improved lethality outcomes for humid conditions but not for dry conditions. Overall, the results from this past year have continued to support the premise that microbial inactivation models are valuable tools for validating pathogen control processes, but that there remain critical gaps in fully describing the impact of key product/process factors on process outcomes. Therefore, it is extremely important to use product-specific inactivation parameters, and appropriate statistical approaches, as developed in this project, when validating pathogen control processes.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Limcharoenchat, P., M. K. James, and B. P. Marks. 2019. Survival and thermal resistance of Salmonella Enteritidis PT 30 on almonds after long-term storage. J. Food Prot. 82:194-199.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Garces-Vega F, Ryser ET, Marks BP. 2019. Relationships of water activity and moisture content to the thermal inactivation kinetics of Salmonella in low-moisture foods. J. Food Prot. 82:963-970.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Ahmad NH, Oztabak C, Marks BP, Ryser ET. 2019. Effect of talc as a dry-inoculation carrier on thermal resistance of Enterococcus faecium NRRL B-2354 in almond meal. J. Food Prot. 82:1110-1115.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Steinbrunner PJ, Limchareonchat P, Suehr QJ, Ryser ET, Marks BP, Jeong S. 2019. Effect of food structure, water activity, and long-term storage on x-ray irradiation for inactivating Salmonella Enteritidis PT30 in low-moisture foods. J. Food Prot. 82:1405-1411.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Tsai HC, Ballom KF, Xia S, Tang J, Marks BP, Zhu MJ. 2019. Evaluation of Enteroccous faecium NRRL B-2354 as a surrogate for Salmonella during cocoa powder thermal processing. Food Microbiology. 82:135-141.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Lee HC, Singh P, Strasburg GM, Marks BP, Jin HW, Kang I. 2019. Comparison of raw meat quality and protein-gel properties of turkey breast fillets processed by traditional or cold-batter mincing technology. Poultry Science. 98:2299-2304.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Jayeola V, Jeong S, Almenar E, Marks BP, Vorst KL, Brown JW, Ryser ET. 2019. Predicting the Growth of Listeria monocytogenes and Salmonella Typhimurium in diced celery, onions, and tomatoes during simulated commercial transport, retail storage, and display. J. Food Prot. 82:287-300.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Marks BP. 2019. Effects of product moisture and process humidity on pathogen lethality during continuous cooking of meat and poultry products. Symposium S15. Presented at the Annual Meeting of the International Association for Food Protection. Louisville, KY. July 21-24, 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Marks BP. 2019. Canning vs. Baking - Everything you thought you knew about D & z. 38th Annual Meeting of the Institute for Thermal Processing Specialists. San Antonio, TX. Feb 26-28, 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Hildebrandt I, Hall N, James M, Ryser E, Marks B. 2019. Humidity affects Salmonella lethality and USDA FSIS Appendix A compliance for impingement-cooked meat and poultry products. Abstract P3-216. Presented at the Annual Meeting of the International Association for Food Protection. Louisville, KY. July 21-24, 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Ahmad NH, Ryser E, Marks B. 2019. Enterococcus faecium NRRL B-2354 as a Salmonella surrogate in validating thermal treatment of dairy powders with different lactose and milk protein compositions. Abstract P1-07. Presented at the Annual Meeting of the International Association for Food Protection. Louisville, KY. July 21-24, 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Steinbrunner P, Ryser E, Dolan K, Marks B, Jeong S. 2019. Quantifying the inactivation of Enterococcus faecium during spray drying. Abstract P1-204. Presented at the Annual Meeting of the International Association for Food Protection. Louisville, KY. July 21-24, 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Marks BP. 2019. Humidity in impingement cooking Salmonella lethality and the revised Appendix A. Presented at the American Meat Science Association Reciprocal Meat Conference. Loveland, CO. June 25-27, 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Marks BP. 2019. Meat, heat, and humidity (and Appendix A!) - What does it all mean? Reciprocation Session at the American Meat Science Association Reciprocal Meat Conference. Loveland, CO. June 25-27, 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Gomez G, Marks B. 2019. Monetizing the impact of food safety recalls on the low-moisture food industry. Abstract P1-144. Presented at the Annual Meeting of the International Association for Food Protection. Louisville, KY. July 21-24, 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Gomez C, Marks B, Ilic S, Paden H, Ryser E, Mitchell J. 2019. Creating a risk model for nosocomial listeriosis in cancer patients who consume ready-to-eat salad. Abstract P1-145. Presented at the Annual Meeting of the International Association for Food Protection. Louisville, KY. July 21-24, 2019.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Hildebrandt I, Riddell L, James M, Hall N, Marks B. 2019. Validation of a cracker baking process using predictive modeling. Abstract P1-208. Presented at the Annual Meeting of the International Association for Food Protection. Louisville, KY. July 21-24, 2019.
|
Progress 10/01/17 to 09/30/18
Outputs
Target Audience:Our current key stakeholders for this project are: (1) Suppliers of pasteurization equipment for the low-moisture food industry, (2) Dry ingredient suppliers, (3) Processors utilizing or producing ready-to-eat, low-moisture food products, and (4) The U.S. Food and Drug Administration (as the relevant regulator). Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The entire research team (including all undergraduates and graduate students) has been trained in advanced laboratory techniques necessary for conducting experiments with biosafety level-2 pathogens in low-moisture powders, which present specific challenges in ensuring worker safety, due to risk of airborne particles during sample preparation and handling. Additionally, 5 members of the project team attended the annual meeting of the International Association for Food Protection, where they presented project results and participated in various Professional Development Groups. How have the results been disseminated to communities of interest?Project results have been shared with key stakeholders (beyond scientific conferences) by the following means in the past year: (1) Presentations an industry trade show - Process Expo 2017, (2) Presentations as part of an on-site, two-day workshop at the Institute for Food Technologists 2018 Annual Meeting, and (3) a webinar distributed by the International Association for Food Protection (603 registrants) in October 2018. What do you plan to do during the next reporting period to accomplish the goals?Overall, during the next reporting period, the project will focus on the following activities: (1) continuing to test novel approaches to modeling the product-process effects on thermal inactivation of Salmonella on/in low-moisture products, (2) conducting additional pilot-scale validation trials, particularly in the areas of baking and meat/poultry cooking (focused on humidity effects), and (3) Developing and testing statistical tools for process validations. First, a significant data set for Salmonella inactivation in baking processes is being acquired from project collaborators, and inactivation models incorporating process humidity and dynamic process moisture content will be tested against these diverse data sets. Based on those results, modeling tools currently in distribution and industry use are anticipated to be modified/improved. Secondly, additional pilot-scale challenge studies will be conducted, in which the effects of product properties and process conditions (e.g., humidity) on Salmonella inactivation will be tested in baking (e.g., crackers), cooking (e.g., meat and poultry products), and various drying processes. In addition to model accuracy, process variability and validation uncertainty will be quantified.
Impacts
What was accomplished under these goals?
The overall project entails four types of activities: (1) lab-scale studies generating microbial response data for the multiple pathogens, products, and processes, (2) development of mathematical models to describe bacteria inactivation and/or transfer, (3) pilot-scale studies to validate those models, and (4) utilization of the models to develop and deploy tools and training directly applicable to commercial applications. By working directly at the interface of food microbiology and engineering, this project is generating unique contributions toward improving the safety of ready-to-eat products, primarily by improving the ability of food processors and food safety regulators to reliably evaluate and validate the efficacy of pathogen reduction processes. A few example accomplishments from the past year are highlighted below. Under Overall Goal 1, Salmonella survival and thermal resistance on the surface of almond kernels were evaluated after periods of storage. Almond kernels were inoculated with Salmonella Enteritidis PT 30 and equilibrated to 0.45 water activity (aw), and stored up to 103 weeks at room temperature prior to isothermal heat treatment (80°C). Log-linear and Weibull models were fit to the inactivation data. Salmonella population decreased (P < 0.05) more than 2 log CFU/g during the long-term storage. However, the thermal resistance of Salmonella Enteritidis PT 30 did not decrease (P > 0.05) for up to 68 weeks of storage, and the log-linear model best described the thermal inactivation data. Overall, the results suggest that Salmonella thermal resistance on almonds appears to be essentially unaffected by long-term storage, which is important information for designing and conducting validation studies for pathogen control processes. Additionally under Overall Goal 1, models were developed to account for the effects of temperature, water activity, and physical structure on Salmonella thermal resistance on/in multiple almond, date, and wheat products. Whole almonds, dates, and wheat kernels were inoculated with Salmonella Enteritidis PT30 and equilibrated to 0.25, 0.45, or 0.65 water activity before fabricating into almond meal, almond butter, wheat meal, wheat flour, and date paste. Inoculated and equilibrated almonds, wheat kernels, and date pieces were vacuum-packed in plastic bags, and fabricated products were subjected to isothermal water bath treatment. Primary (log-linear and Weibull) and secondary (Bigelow-type) models were applied to inactivation data (triplicate) to estimate parameters. Overall, model fits yielded RMSEs of 0.47 to 1.08 log CFU/g. The highest Salmonella thermal resistance was in almond meal (D80°C, 0.25aw = 75.2 min), and lowest was in date paste (D80°C, 0.65aw = 0.7 min). There were no structure effects for wheat products (P > 0.05), but Salmonella thermal resistance in fabricated almond and date products were higher (P < 0.05) than on kernels and pieces. Overall, thermal resistance increased with decreasing aw (P < 0.05). The results show that water activity and structure of low-moisture products are critical factors that must be considered when validating pathogen controls for ingredients or formulated products. Under Overall Goal 2, a reliability analysis approach was utilized to assess the utility of a non-pathogenic surrogate organism (Enterococcus faecium NRRL B-2354) for validating Salmonella lethality in pathogen reduction processes. Two different inactivation data-sets for the surrogate and pathogen were obtained. The data consisted of thermal inactivation curves for both bacteria on multiple low-moisture foods (e.g., walnuts and almond meal) at different process temperatures, air velocities, and process humidities (~120 data points). A linear model was fit to the corresponding log-reductions of both organisms. Estimations of the log-reduction of the pathogen from 4 log-reductions of the surrogate were performed, implementing a Monte-Carlo simulation (n=1,000). Performance of the surrogate (% of log- reductions of pathogen >4), and the log-reduction of surrogate necessary to achieve >4 log-reductions of the pathogen 90% of the time were estimated. The linear fit of the two paired log-reduction data-sets yielded good fits, with RMSE = 1.14 and 0.45, slope = 0.49 and 1.2, and intercept = 1.6 and 0.14 for walnuts and almond meal, respectively. The reliability analysis shows that when on average 4 log-reductions of the surrogate are observed, 4 log-reductions of the pathogen are expected 37% and 83% of the time, respectively. The level of inactivation necessary to achieve a reliability of 90% was 7.8 and 3.9 log-reductions of the surrogate. These results show that reliability analysis is a useful tool in assessing performance of surrogates for process validation, which is a critical, but rarely documented, step that should be included in interpretation of process validation results. Subsequently, a study was conducted to quantify the impact of experimental design on the potential for surrogate-based process validations to discriminate between effective and ineffective preventative controls. Multiple sampling plans were evaluated for the likelihood (statistical power) of correctly reporting effective (95% of possible samples above target lethality) or non-effective preventative controls. Using a Monte Carlo-based Bayesian approach, pre- and post- treatment samples were randomly generated and tested (using confidence and prediction intervals, α=0.05) to determine if the target lethality was achieved, repeating this process 1,000 times. The percentage of results correctly classifyingtreatment effectiveness approximated the statistical power of the plan. Variables included the sampling design (≥3 samples before/after treatment, ≥2 replications), sampling error, achievable lethality, and replication error. With true mean lethality ≤ target lethality, all sampling plans achieved ≥99% likelihood of correctly indicating an ineffective treatment. Using the minimal sampling design on a barely-effective treatment (e.g., lower 95% prediction of achieved lethality was only 0.2 greater than the target), only 66% of the experiments indicated the treatment as effective. With the same barely-effective treatment, collecting 10 samples pre- and post-treatment with 5 replications increased the probability of correctly indicating the treatment as effective to 88%. Overall, this study demonstrated that statistical power of sampling designs depended on preventative control effectiveness; largely effective or ineffective treatments required fewer samples than borderline effective treatments. The prediction interval was the most sensitive metric to evaluate treatment sufficiency, making it an important measurement that should be utilized for validation experiments. Overall, the results from this past year have continued to support the premise that low-moisture pasteurization processes need to be validated for different types of products and processes, given that efficacy can be affected by product structure, water activity, etc. Therefore, it is extremely important to use product-specific inactivation parameters, and appropriate statistical approaches, as developed in this project, when validating pasteurization processes.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Casulli KE, Garces-Vega FJ, Dolan KD, Ryser ET, Harris LJ, Marks BP. 2018. Impact of process temperature, humidity, and initial product moisture on thermal inactivation of Salmonella Enteritidis PT 30 on pistachios during hot-air heating. Journal of Food Protection. 81:1351-1356.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Limcharoenchat P, Buchholz SE, James MK, Hall NO, Ryser ET, Marks BP. 2018. Inoculation protocols influence the thermal resistance of Salmonella Enteritidis PT30 in fabricated almond, wheat, and date products. Journal of Food Protection. 81:606-613.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2018
Citation:
Limcharoenchat P, James MK, Marks BP. 2018. Survival and Thermal resistance of Salmonella Enteritidis PT 30 on almonds after long-term storage. Journal of Food Protection. Accepted for publication.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Hildebrandt I, Marks B. 2018. Factors influencing Salmonella survival kinetics in low-moisture foods during storage. ASABE Paper No. 1801604. Presented at the Annual International Meeting of the American Society of Biological and Agricultural Engineers. Detroit, MI. Jul 29 - Aug 1, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Garc�s-Vega F, Marks B, James M. 2018. Using reliability analysis to assess the utility of non-pathogenic surrogates. Abstract P3-107. Presented at the Annual Meeting of the International Association for Food Protection. Salt Lake City, UT. July 8-11, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Hildebrandt I, Marks B. 2018. Quantification of statistical power for surrogate-based lethality validation studies. Abstract P3-126. Presented at the Annual Meeting of the International Association for Food Protection. Salt Lake City, UT. July 8-11, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Ahmad N, DSouza RC, Hildebrandt I, Thippareddi H, Marks B, Ryser E. 2018. Validation of Enterococcus faecium NRRL B-2354 as a surrogate for thermal inactivation of Salmonella in date paste. Abstract P2-87. Presented at the Annual Meeting of the International Association for Food Protection. Salt Lake City, UT. July 8-11, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Ahmad N, Oztabak C, Marks B, Ryser E. 2018 Effect of talc on thermal resistance of Enterococcus faecium NRRL B-2354 in almond meal at a water activity of 0.45. Abstract P2-88. Presented at the Annual Meeting of the International Association for Food Protection. Salt Lake City, UT. July 8-11, 2018.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2018
Citation:
Limcharonechat, Pichamon. 2018. Effects of product structure, temperature, water activity, and storage on the thermal resistance of Salmonella Enteritidis PT 30 in low-moisture foods. Ph.D. Dissertation. Michigan State University. East Lansing, MI.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Limcharoenchat P, James M, Hall N, Dolan K, Marks B. 2018. Effects of temperature, water activity, and physical structure on thermal resistance of Salmonella Enteritidis PT30 on multiple almond, date, and wheat products. Abstract P2-91. Presented at the Annual Meeting of the International Association for Food Protection. Salt Lake City, UT. July 8-11, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Steinbrunner P, Ryser, E, Dolan K, Marks B, Jeong S. 2018. Modeling inactivation of Salmonella during spray drying. Abstract P2-97. Presented at the Annual Meeting of the International Association for Food Protection. Salt Lake City, UT. July 8-11, 2018.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2017
Citation:
Maz�n Villegas, Beatriz. 2017. Multiple approaches to quantitatively evaluating bacterial pathogen transfer between food products and contact surfaces. Ph.D. Dissertation. Michigan State University. East Lansing, MI.
|
Progress 10/01/16 to 09/30/17
Outputs
Target Audience:Our current key stakeholders for this project are: (1) Suppliers of pasteurization equipment for the low-moisture food industry, (2) Dry ingredient suppliers, (3) Processors utilizing or producing ready-to-eat, low-moisture food products, and (4) The U.S. Food and Drug Administration (as the relevant regulator). Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The entire research team (including 9 undergraduates and 5 graduate students) has been trained in advanced laboratory techniques necessary for conducting experiments with biosafety level-2 pathogens in low-moisture powders, which present specific challenges in ensuring worker safety, due to risk of airborne particles during sample preparation and handling. Additionally, 7 members of the project team attended the annual meeting of the International Association for Food Protection, where they presented project results and participated in various Professional Development Groups. How have the results been disseminated to communities of interest?Project results have been shared with key stakeholders (beyond scientific conferences) by the following means in the past year: (1) Presentations at the Low-Moisture Task Force pre-meeting at the Institute for Food Safety and Health (IFSH) meeting in Chicago, IL and (2) An on-site, all-day workshop at the International Association for Food Protection Annual Meeting What do you plan to do during the next reporting period to accomplish the goals?Overall, during the next reporting period, the project will focus on the following activities: (1) continuing to test product factors affecting bacterial resistance to lethal treatments for a matrix of additional products, (2) testing novel approaches to modeling the product-process effects on thermal inactivation of Salmonella on/in low-moisture products, and (3) conducting additional pilot-scale validation trials. First, experimental studies continue to focus on generating novel lab-based data documenting the complex interactions between product moisture content, water activity, adsorption/desorption state, and process humidity on thermal resistance of Salmonella on/in low-moisture products (i.e., nuts and cereal products). Novel inactivation model forms are continuing to be developed and tested. Secondly, pilot-scale challenge studies are being conducted to validate new models incorporating both moisture content and humidity in predicting Salmonella inactivation during a variety of pathogen reduction processes, including spray drying, roasting, and steam-enhance pasteurization processes. In addition to model accuracy, process variability and validation uncertainty are being quantified.
Impacts
What was accomplished under these goals?
The overall project entails four types of activities: (1) lab-scale studies generating microbial response data for the multiple pathogens, products, and processes, (2) development of mathematical models to describe bacteria inactivation and/or transfer, (3) pilot-scale studies to validate those models, and (4) utilization of the models to develop and deploy tools and training directly applicable to commercial applications. By working directly at the interface of food microbiology and engineering, this project is generating unique contributions toward improving the safety of ready-to-eat products, primarily by improving the ability of food processors and food safety regulators to reliably evaluate and validate the efficacy of pathogen reduction processes. A few example accomplishments from the past year are highlighted below. Under the area of inactivation modeling, the reproducibility of Salmonella thermal resistance results were tested across six independent research groups. The D80C values for Salmonella Agona in oat flour at 0.45 water activity (aw) were 28.7, 29.7, 30.8, 32.2, 30.3, and 20.0 min. Although shipping, heating medium, and treatment vessel did not significantly affect the D80C values, one laboratory yielded a lower D80C value (P<0.05). Potential root causes were identified and incorporated into standard operating procedures (SOPs). However, the results demonstrated a generally high degree of reliability, with D80C relative errors ranging from 2.3 to 5.8%. This study has demonstrated the feasibility for highly reproducible results across multiple laboratories, but also has reinforced the importance of strictly following experimental controls and SOPs. In another study focused on inactivation modeling, inoculated almonds were equilibrated to two moisture (%MC) levels but the same aw, and two aw levels but the same %MC. Equilibrated products were vacuum packaged and thermally treated in a water bath at 80°C. Survivors were recovered and enumerated, the resulting inactivation curves were used to fit the log-linear inactivation model, and the inactivation kinetics were compared. D?values ranged from 15.7 to 18.0 min, and the RMSE was 0.25 to 0.69 log CFU/g. No differentiated effect attributable preferentially to aw or %MC was seen in the inactivation kinetics (P > 0.05), likely because of the variability of the parameters. However, there are other effects of the two water metrics that should be further studied. To assess the effect of process condition, inoculated almonds were equilibrated at 25 and 65% RH. After equilibration, samples at each moisture content were treated in a laboratory-scale convection oven at four different conditions (121°C, 2 air velocities, and 2 humidities (~3 and 30% moisture by volume)), for 7 durations in triplicate. Survivors were recovered and enumerated. The resulting 24 inactivation curves were used to globally estimate the parameters of six inactivation models. A model incorporating temperature, process humidity, and air velocity performed best, with a RMSE of 0.51 log N/N0. The separate effects of aw and %MC on the inactivation kinetics of Salmonella in LMF remain inconclusive. Further analysis is needed to identify which metric is best for modeling and validating thermal inactivation processes. However, the effect of air velocity was significant, indicating a velocity effect independent of the influence on heating rate, due to the relative impact of product and process moisture on bacterial inactivation. Validation studies with other products will be important to further test the magnitude of the impact of aw, %MC, and air velocity on thermal inactivation processes for low-moisture foods. In the area of process validation, thermal resistances of E. faecium (a nonpathogenic surrogate) and a five-strain Salmonella cocktail (Agona, Enteritidis, Tennessee, Montevideo, and Mbandaka) are being compared in six representative low-moisture foods, across five different laboratories. Salmonella showed lower (P<0.05) thermal resistance than E. faecium in almond meal, peanut butter, and non-fat dried milk powder. E. faecium and Salmonella showed less thermal resistance in almond meal than in peanut butter, in spite of similar fat contents. Overall, E. faecium appears to be a robust surrogate for Salmonella across multiple low-moisture products; however, product characteristics significantly impact that relationship. It is therefore necessary to consider product composition when validating thermal processes for low aw foods. Based on the results of both of these studies, the project team now is disseminating SOPs (for product inoculation and treatment) to peer research groups outside this project team, which will enhance of the comparability and therefore value of low-moisture food safety research nationally. Another study on process validation focused on thermal processing of pistachios. To determine the feasibility of using E. faecium as a surrogate, Salmonella- and E. faecium-inoculated pistachios were treated side-by-side in a pilot-scale oven at 47 combinations of temperature (104.4 and 118.3C), initial moisture content (6 and 9% moisture content, dry basis), presoak (no presoak, water presoak, salt brine presoak), and humidity conditions (measured as dew points, 16, 54, and 69C; corresponding to absolute humidities of 1, 15, and 30%). E. faecium was a conservative surrogate for Salmonella, showing more conservative estimates at greater log reductions. On average, E. faecium showed lower inactivation than Salmonella (P < 0.05). To validate the previously developed model, six replicates of four conditions (either 16 or 69C dew point and either dry or salt brine presoak) were conducted with Salmonella-inoculated pistachios. Pistachio surface temperature data were collected every 2 s during each treatment, and dew point was monitored and recorded. End-point moisture data were also collected. In general, the model showed conservative predictions, with an overall RMSE of 0.74 logCFU/g. There was some bias observed across treatments, with model predictions closer to experimental outcomes for no presoak / 16C dew point and salt brine presoak / 69C dew point conditions (RMSE of 0.32 logCFU/g and 0.34 logCFU/g, respectively). In contrast, observations for no presoak / 69C dew point and salt brine presoak / 16C dew point conditions showed less accuracy as compared to model predictions (RMSE of 1.11 logCFU/g and 0.87 logCFU/g, respectively). These results indicate that both E. faecium- and model-based validations are suitable, conservative estimates for Salmonella inactivation during pistachio roasting under the conditions evaluated. Overall, the results from this past year have continued to support the premise that low-moisture pasteurization processes need to be validated for different types of products, given that efficacy can be affected by product structure, water activity, etc. Therefore, it is extremely important to use product-specific inactivation parameters, as developed in this project, when validating pasteurization processes.
Publications
- Type:
Journal Articles
Status:
Under Review
Year Published:
2018
Citation:
Limcharoenchat P, Buchholz SE, James MK, Hall NO, Ryser ET, Marks BP. 2018. Inoculation protocols influence the thermal resistance of Salmonella Enteritidis PT30 in fabricated almond, wheat, and date products. Journal of Food Protection. In review.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Jeong S., Marks BP, James MK. 2017. Comparing thermal process validation methods for Salmonella inactivation on almond kernels. Journal of Food Protection. 80:169-176.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Villa-Rojas R, Zhu MJ, Marks BP, Tang J. 2017. Radiofrequency inactivation of Salmonella Enteritidis PT30 and Enterococcus faecium in wheat flour at different water activities. Biosystems Engineering. 156:7-16.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Marks BP. 2017. Challenges in food engineering education and research. Presented at the Annual International Meeting of the American Society of Agricultural and Biological Engineers. Spokane, WA. July 16-19, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Casulli, K, Dolan KD, Marks BP. 2017. Evaluation of process validation methods for Salmonella inactivation in pistachios. IFT Abstract 01-029. Presented at the Annual Meeting of the Institute of Food Technologists. Las Vegas, NV. June 25-28, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Marks BP. 2017. Modifying Existing (Legacy) Thermal Processes to Achieve Pathogen Reduction Goals. Symposium S45. Presented at the Annual Meeting of the International Association for Food Protection. Tampa, FL. July 9-12, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Hildebrandt I, Marks B. 2017. Optimal Isothermal Data Collection Practices for Estimating Microbial Thermal Inactivation Parameters. Abstract P1-150. Presented at the Annual Meeting of the International Association for Food Protection. Tampa, FL. July 9-12, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Garces-Vega F, Marks BP. 2017. Can Adsorption-Desorption State Affect Salmonella Thermal Inactivation Kinetics in Low-Moisture Foods? Abstract T6-06. Presented at the Annual Meeting of the International Association for Food Protection. Tampa, FL. July 9-12, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Ahmad N, Hildebrandt I, Pickens S, Lau SK, Xu J, Liu S, Tsai HC, Rincon AM, Subbiah J, Thippareddi, H, Zhu M, Tang J, Anderson N, Grasso-Kelley E, Ryser E, Marks B. 2017. Utilization of E. faecium As a Salmonella Surrogate for Thermal Treatment in Selected Low-Moisture Food Products. Abstract T6-12. Presented at the Annual Meeting of the International Association for Food Protection. Tampa, FL. July 9-12, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Ahmad N, Tsai HC, Hildebrandt I, Zhu M, Tang J, Marks B, Ryser E. 2017. Validation of Enterococcus faecium as a Salmonella Surrogate in Thermal Treatment of Almond Meal. Abstract P3-02. Presented at the Annual Meeting of the International Association for Food Protection. Tampa, FL. July 9-12, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Hildebrandt I, Pickens S, Lau SK, Subbiah J, Anderson N, Marks B, Grasso-Kelley E. 2017.Multi-Laboratory Comparison of Thermal Resistance of Enterococcus faecium and Salmonella Enterica in Peanut Butter. Abstract P3-05. Presented at the Annual Meeting of the International Association for Food Protection. Tampa, FL. July 9-12, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Liu S, Ahmad N, Xu J, Hildebrandt I, Ryser E, Zhu M, Marks B, Tang J. 2017.Enterococcus faecium As a Surrogate for Salmonella in Thermal Treatment of Non-Fat Milk Powder. Abstract P3-07. Presented at the Annual Meeting of the International Association for Food Protection. Tampa, FL. July 9-12, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Garces-Vega F, Casulli K, Marks B. 2017. The Effect of Process Air Velocity, Humidity, and Product Moisture on Salmonella Inactivation on Almonds. Abstract P3-08. Presented at the Annual Meeting of the International Association for Food Protection. Tampa, FL. July 9-12, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Schwartz R, Williams J, Limcharoenchat P, Hall N, James M, Marks B. 2017.Effect of Temperature, Water Activity, and Structure on Salmonella Thermal Resistance in Multiple Wheat Products. Abstract P3-09. Presented at the Annual Meeting of the International Association for Food Protection. Tampa, FL. July 9-12, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Steinbrunner P, Limcharoenchat P, Marks B, Jeong S. 2017.Effect of Long-Term Almond Storage on Survival and Resistance of Salmonella to Heat and X-Ray. Abstract P3-12. Presented at the Annual Meeting of the International Association for Food Protection. Tampa, FL. July 9-12, 2017.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Tsai HC, Song X, Tang J, Marks B, Zhu M. 2017. Is Enterococcus faecium an Appropriate Surrogate for Salmonella in Thermal Process Validation of Cocoa Powder? Abstract P3-14. Presented at the Annual Meeting of the International Association for Food Protection. Tampa, FL. July 9-12, 2017.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2017
Citation:
Garces-Vega FJ. 2017. Quantifying Water Effects on Thermal Inactivation of Salmonella in Low-Moisture Foods. Ph.D. Dissertation. Michigan State University. East Lansing, MI.
|
Progress 03/02/16 to 09/30/16
Outputs
Target Audience:Our key stakeholders for this project are: (1) Suppliers of pasteurization equipment for the low-moisture food industry, (2) Dry ingredient suppliers, (3) Processors utilizing or producing ready-to-eat, low-moisture food products, and (4) The U.S. Food and Drug Administration (as the relevant regulator). Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The entire research team (including 9 undergraduates and 5 graduate students) previously was trained in advanced laboratory techniques necessary for conducting experiments with biosafety level-2 pathogens in low-moisture powders, which present specific challenges in ensuring worker safety, due to risk of airborne particles during sample preparation and handling. Additionally, 9 members of the project team attended the annual meeting of the International Association for Food Protection, where they presented project results and participated in various Professional Development Groups. How have the results been disseminated to communities of interest?Project results have been shared with key stakeholders (beyond scientific conferences) by the following means in the past year: (1) Presentations at the Low-Moisture Task Force pre-meeting at the Institute for Food Safety and Health (IFSH) spring meeting in Chicago, IL and (2) A nationally distributed webinar. What do you plan to do during the next reporting period to accomplish the goals?Overall, during the next reporting period, the project will focus on the following activities: (1) continuing to test product factors affecting bacterial resistance to lethal treatments for a matrix of additional products, (2) testing novel approaches to modeling the product-process effects on thermal inactivation of Salmonella on/in low-moisture products, and (3) conducting additional pilot-scale validation trials. First, experimental studies currently are focused on generating additional lab-based data quantifying the complex interactions between product moisture content, water activity, adsorption/desorption state, and process humidity on thermal resistance of Salmonella on/in low-moisture products (i.e., nuts and cereal products). Novel inactivation model forms are being developed and tested. Additionally, Salmonella thermal resistance (a five-strain, outbreak-linked cocktail) is quantitatively being compared against Enterococcus faecium (a nonpathogenic surrogate) across six different low-moisture products in a cross-laboratory collaboration encompassing five different laboratories. Secondly, pilot-scale challenge studies are being conducted to validate new models incorporating both moisture content and humidity in predicting Salmonella inactivation during pistachio roasting/pasteurization, spray drying, and other inactivation processes. In addition to model accuracy, process variability and validation uncertainty are being quantified.
Impacts
What was accomplished under these goals?
The overall project entails four types of activities: (1) lab-scale studies generating microbial response data for the multiple pathogens, products, and processes, (2) development of mathematical models to describe bacteria inactivation and/or transfer, (3) pilot-scale studies to validate those models, and (4) utilization of the models to develop and deploy tools and training directly applicable to commercial applications. By working directly at the interface of food microbiology and engineering, this project is generating unique contributions toward improving the safety of ready-to-eat products, primarily by improving the ability of food processors and food safety regulators to reliably evaluate and validate the efficacy of pathogen reduction processes. A few example accomplishments from the past year are highlighted below. In one study, we tested the impact of moisture equilibration rate on adaptive bacterial resistance to heat. Two dynamic moisture treatments were compared to two static moisture treatments to determine the effect of time-at-moisture on thermal resistance of Salmonella Enteritidis PT 30 in wheat flour. Inoculated samples were subjected to isothermal (80°C) heat treatments after slow (4-7 d) or rapid (2-4 min) equilibration to target water activities (aw), and Salmonella thermal resistance was compared via decimal reduction times (i.e., D80°C values). The D80°C value in flour that was rapidly desiccated from 0.6 to 0.3 aw was statistically equivalent (P > 0.05) to the D80°C value in flour previously equilibrated to 0.3 aw, but both were greater (P < 0.05) than the D80°C value in flour previously equilibrated to 0.6 aw. Similarly, the D80°C value in flour rapidly hydrated from 0.3 to 0.6 aw was statistically equivalent (P > 0.05) to the D80°C value in flour previously equilibrated to 0.6 aw, and both were less than the D80°C value in flour previously equilibrated to 0.3 aw. Therefore, Salmonella in the rapidly desiccated flour (0.3 aw) was as thermally resistant as that which previously had been equilibrated to 0.3 aw, and Salmonella in the rapidly hydrated flour (0.6 aw) responded similarly to that in the flour previously equilibrated to 0.6 aw. These results suggest that the response period to new aw is negligible, which is critically important in applying thermal resistance data or parameters to industrial pasteurization validations. We also have evaluated Salmonella thermal resistance on inoculated almonds stored for long periods. To date, Salmonella-inoculated almonds (~0.45 water activity) have been stored at room temperature for 12 mos, with the thermal resistance (D80°C) quantified five times during the storage period. Salmonella thermal resistance was unchanged (P > 0.05) during the storage study, further indicating the significant challenge of managing a pathogen that is both persistent and highly thermally resistance even after long periods of desiccated storage. Several aspects of this project have continued to develop, test, and report on alternative approaches to modeling the effect of product and process variables on Salmonella resistance to lethal treatments in low-moisture foods. In one study, multiple secondary models were tested for the effect of product (wheat flour) aw on Salmonella Enteritidis PT30 thermal resistance. A full-factorial experimental design included three temperatures (75, 80, and 85°C) and four water activities (~0.30, 0.45, 0.60, and 0.70 at 24ºC). Prior to isothermal treatment, sample aw was achieved by equilibrating samples within a humidity-controlled conditioning chamber. Two primary models (log-linear and Weibull-type) and three secondary models (second-order response surface, modified Bigelow-type, and combined-effects) were evaluated using the corrected Aikake Information Criterion (AICc) and root mean squared errors (RMSE). Statistical analyses of the primary models favored the log-linear model. Incorporating the three secondary models into the log-linear primary model yielded RMSE values of 2.1, 0.78, and 0.96 log CFU/g and AICc values of 460, -145, and -19 for the response surface, modified Bigelow, and combined-effects models, respectively. The modified Bigelow-type model, which exponentially scaled both temperature and aw effects on thermal inactivation rates, predicted Salmonella lethality significantly better (P < 0.05) than did the other secondary models examined. Overall, aw is a critical factor affecting thermal inactivation of Salmonella in low-moisture products, and should be appropriately included in thermal inactivation models for these types of systems. Although water activity has been the primary variable used in prior studies when quantifying the effect of moisture on Salmonella thermal resistance, our results have demonstrated that this approach is not likely to work as a generalized metric across all low-moisture products. In one aggregate analysis, D80°C values for Salmonella Enteritidis PT30 were calculated by linear regression of isothermal inactivation data from multiple studies (wheat flour, almonds, dates; 0.25, 0.45, 0.65 aw; 70-90°C). Water activity and %mc were measured and/or calculated from moisture isotherms (sorption and desorption, accordingly). Linearity of inactivation curves was confirmed, and correlation coefficients were estimated between logD and aw and %mc. The D80°C values for the different products exhibited a log-linear trend with aw, as well as with %mc. The correlation coefficients varied less than 5% when comparing aw and %mc vs. logD (e.g., -0.96 and -0.95, respectively, for wheat flour). The results suggest that %mc may be a suitable, or even preferable, metric for the effect of water on inactivation process. When comparing the utility of aw vs. %mc for inactivation modeling or process validation, %mc has the advantage of being measurable (potentially real-time in dynamic processes), and this study shows a consistent correlation with logD. This is critically important to both monitoring and modeling inactivation processes in low-moisture foods. The results from this past year have continued to support the premise that low-moisture pasteurization processes need to be validated for different types of products, given that efficacy can be affected by product structure, water activity, etc. Therefore, it is extremely important to use product-specific inactivation parameters, as developed in this project, when validating pasteurization processes.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2016
Citation:
Jeong S., Marks BP, James MK. 2016. Comparing thermal process validation methods for Salmonella inactivation on almond kernels. Journal of Food Protection. Accepted for publication.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2016
Citation:
Smith DF, Hildebrandt IM, Casulli KE, Dolan KD, Marks BP. 2016. Modeling the effect of temperature and water activity on the thermal resistance of Salmonella Enteritidis PT30 in wheat flour. Journal of Food Protection. In press.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2016
Citation:
Hildebrandt IM, Marks BP, Ryser ET, Villa-Rojas R, Tang J, Garces-Vega FJ, Buchholz SE. 2016. Effects of inoculation procedures on variability and repeatability of thermal resistance of Salmonella in wheat flour. Journal of Food Protection. In press.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Buchholz S, Limcharoenchat P, Hall N, Jeong S, Ryser E, Marks B. 2016. Effects of temperature, water activity, and structure on thermal resistance of Salmonella in dates and date paste. Abstract P2-03. Presented at the Annual Meeting of the International Association for Food Protection. July 31 Aug 3, 2016. St. Louis, MO.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Limcharoenchat P, James M, Hall N, Marks B. 2016. Moisture equilibration and product fabrication methods affect measured thermal resistance of Salmonella Enteritidis PT30 on/in whole almonds, almond meal, and almond butter. Abstract P2-05. Presented at the Annual Meeting of the International Association for Food Protection. July 31 Aug 3, 2016. St. Louis, MO.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Garces-Vega F, Jeong S, Dolan K, Marks B. 2016. Modeling Salmonella inactivation in low moisture foods: using parameter estimation to improve model performance. Procedia Food Science. 7:41-46.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Carroll LM, Bergholz TM, Hildebrandt IM, Marks BP. 2016. Application of a nonlinear model to transcript levels of upregulated stress response gene ibpa in stationary-phase Salmonella enterica subjected to sublethal heat stress. Journal of Food Protection. 79:1089-1096.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2016
Citation:
Syamaladevi RM, Tadapaneni RK, Xua J, Villa-Rojas R, Tang J, Carter B, Sablani S, Marks B. 2016. Water activity change at elevated temperatures and thermal resistance of Salmonella in all purpose wheat flour and peanut butter. Food Research International. 81:163-170.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Steinbrunner P, Suehr Q, Jeong S, Marks B. 2016. Effect of product structure and water activity on x-ray inactivation of Salmonella in low-water activity foods. Abstract P2-13. Presented at the Annual Meeting of the International Association for Food Protection. July 31 Aug 3, 2016. St. Louis, MO.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Garces-Vega F, Marks B. 2016. Evaluation of water content as a convenient metric in thermal inactivation modeling for low-moisture foods. Abstract P2-17. Presented at the Annual Meeting of the International Association for Food Protection. July 31 Aug 3, 2016. St. Louis, MO.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Casulli, KE, Garces-Vega FJ, Dolan KD, Marks BP. 2016. Impact of temperature, moisture, and humidity on thermal inactivation of Salmonella in pistachios heated under dynamic processing conditions. Presented at the XIII Latin American Congress of Microbiology and Food Hygiene. September 27-30, 2016. Medell�n, Colombia.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Harris LJ and Marks BP. 2016. The impact of water and product composition on pathogen survival and inactivation. Symposium S21. Presented at the IAFP European Symposium on Food Safety. 11-13 May 2016. Athens, Greece.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Hildebrandt I, Anderson N, Limcharoenchat P, Hall N, Xu J, Zhu M, Marks B, Tang J, Grasso-Kelley E. 2016. Quantifying reproducibility of Salmonella thermal resistance through a multi-laboratory comparison. Abstract P2-06. Presented at the Annual Meeting of the International Association for Food Protection. July 31 Aug 3, 2016. St. Louis, MO.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Carroll J, Suehr Q, Steinbrunner P, Marks B, Ryser E. Jeong S. 2016. Factors affecting bacterial cross-contamination using Salmonella and a surrogate organism during almond processing. Abstract P2-20. Presented at the Annual Meeting of the International Association for Food Protection. July 31 Aug 3, 2016. St. Louis, MO.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Suehr Q, Marks B, Ryser E, Jeong S. 2016. Scalability of a discrete element model for Salmonella cross-contamination in granular low-water activity foods. Abstract P2-18. Presented at the Annual Meeting of the International Association for Food Protection. July 31 Aug 3, 2016. St. Louis, MO.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Casulli K, Garces-Vega F, Dolan K, Harris LJ, Marks B. 2016. Modeling the effect of product temperature, moisture, and process humidity on thermal inactivation of Salmonella in pistachios. Abstract P2-19. Presented at the Annual Meeting of the International Association for Food Protection. July 31 Aug 3, 2016. St. Louis, MO.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Marks BP. 2016. Validating legacy processing systems: application of thermal resistance data and models to predict log reductions in dynamic processes. Symposium 096. Presented at the Annual Meeting of the Institute of Food Technologists. July 19, 2016. Chicago, IL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Casulli KE, Dolan KD, Marks BP. 2016. Performance of Enterococcus faecium as a nonpathogenic surrogate for Salmonella during pistachio roasting. Abstract 17. Presented at the Conference on Food Engineering. Columbus, OH. September 12-14, 2016.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Marks BP. 2016. Utilizing microbial inactivation models to validate pathogen-reduction processes for low-moisture foods: challenges, opportunities, and pitfalls. Presented at the Conference on Food Engineering. Columbus, OH. September 12-14, 2016.
|
|