IMPROVEMENT OF THERMAL AND ALTERNATIVE PROCESSES FOR FOODS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0205879
• Multistate No.: NC-1023
• Project Start Date: Oct 1, 2005
• Project End Date: Sep 30, 2010
• Program Code: [(N/A)]- (N/A)

Recipient Organization
OREGON STATE UNIVERSITY
(N/A)
CORVALLIS,OR 97331

Performing Department
FOOD SCIENCE AND TECHNOLOGY

Non Technical Summary
Although thermal processing is the prevailing method to achieve the stability and safety of many foods, the elevated temperatures used have undesirable effects on their "freshness" and "natural" properties. High pressure processing (HPP) is a novel process that can be applied at refrigeration, room-temperature, or with moderate heating to inactivate pathogens and spoilage microorganisms in foods. Pressure alone has minimum effects on covalent bonds and does not alter the chemical composition of foods. Processing foods under high pressure reduces and often eliminates the use of additives and chemical preservatives. In most cases, this technology requires significantly less energy than traditional heat processing. The successful introduction of a new technology demands competitive advantages over existing ones. In the case of HPP, an additional constraint is the large capital investment which is overcome by operating HPP plants at full capacity. The following examples show the many opportunities in which HPP has a clear competitive advantage: (1) Unsatisfied consumer demand for fresh products free from chemical additives; (2) Pressure processing effect is unique and cannot be replicated with other technologies; (3) Product is a high microbial risk to produce and only HPP can eliminate costly recalls and prevent damage to the reputation of the producer; and (4) Product has a high value and cannot be stabilized by conventional processes because of the lability of key ingredient(s).

Animal Health Component

40%

Research Effort Categories

Basic

40%

Applied

40%

Developmental

20%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
501	1040	1130	10%
501	3110	2020	10%
501	3430	2020	10%
501	3450	1000	10%
501	3470	2020	10%
501	4010	1100	20%
501	4020	1102	10%
501	7299	2020	10%
502	1451	1000	10%

Knowledge Area
501 - New and Improved Food Processing Technologies; 502 - New and Improved Food Products;

Subject Of Investigation
3430 - Cheese; 1451 - Onion, garlic, leek, shallot; 4010 - Bacteria; 4020 - Fungi; 3110 - Insects; 3450 - Milk; 7299 - Research equipment and methods, general/other; 3470 - Other dairy cattle products; 1040 - Mango;

Field Of Science
2020 - Engineering; 1130 - Entomology and acarology; 1100 - Bacteriology; 1102 - Mycology; 1000 - Biochemistry and biophysics;

Keywords

high pressure processing

bacterial spores

spore germination

pressure ph shift

antimicrobial compounds

optical measurements

food safety

Goals / Objectives
1. To develop and verify methods for characterization, measurement and prediction of engineering and biochemical properties of foods as needed in process design and analysis, and product development. 2. To measure and model process dependent kinetic parameters which affect food quality and safety attributes. 3. To identify and characterize transport mechanisms occurring in food processes. 4. To develop mathematical models for simulation, prediction, design, and improvement of food processes.

Project Methods
The contributions from Oregon will focus on enhancing the effectiveness of pressure processing to expand the range of products that could benefit from this novel technology. This will include the effects of pressure pH shifting, adiabatic heat of compression, pressure pulsing and chemical additives. Approach 1: Weak acids (HA) naturally present or added to food establish equilibrate between the undissociated acid (HA) and its ions (A- and H+). Water forms condensed layers around these charged species producing an overall volume change that is negative for negatively charged anions and positive otherwise. This causes a temporary pH shift while foods are under pressure. This is being investigated with vegetative cells as well as bacterial spores. Negative pH shift can increase pressure lethality and the effectiveness of antimicrobial compounds by shifting the equilibrium towards the more effective undissociated form of antimicrobials. Approach 2: Adiabatic heat of compression results also in temporary increases of food temperature. These are important when inactivating bacterial spores by processes with food initially at 70-100C. There is a need for inactivation rate data under high pressure/high temperature for bacterial spores causing food spoilage and food poisoning. The contribution from Oregon will focus on Clostridium perfringens and Clostridium sporogenes. Approach 3: Under resting conditions, bacterial spores are resistant to pressure. However, upon activation they begin to loose their resistance particularly when they have reached stage II defined by cortex hydrolysis and core hydration and expansion. Heat and pressure are signals that activate this germination process but its kinetics is known only under limited conditions and mostly for Bacillus subtilis spores. The contribution from Oregon will focus on obtaining this information for C. perfringens and C. sporogenes for heat, pressure and heat/pressure combinations. Approach 4: Bacterial spores can also be activated by chemical signals including GRAS status compounds. Again, the literature is limited to studies in B. subtilis and C. botulinum. The contribution from Oregon will focus on the germination kinetics for C. perfringens and C. sporogenes spores (untreated or heat-, pressure- and heat/pressure-shocked) as affected by sugars (glucose, fructose), aminoacids (alanine, serine, histidine, valine), lactate, inosine, calcium chloride. In the experimental procedures for approaches 2-4, it is important to control pH shifting. Our strategy will be to use pH buffer combinations that result in zero pH shifting. This can be achieved by using mixtures of buffers with negative and positive volume changes. Additional research activities: In addition to demonstrating the microbial safety advantages of pressure processing, we will characterize flavor compounds formed under combined pressure/heat combinations with an emphasis on refrigerated and shelf-stable milk. In-line/real-time optical measurements are versatile, have high sensitivity and we will demonstrate their potential for food quality control and research applications including pressure processing.

Progress 10/01/05 to 09/30/10

Outputs
OUTPUTS: (1) New technologies: Food process engineering principles must be used to allow the optimization of novel and conventional food processes. For example, our research on the implementation of pressure-assisted thermal processing (PATP) requires an analysis of chemical reaction kinetics at high pressure and elevated temperature. While the effect of temperature is predictable (i.e., all chemical reactions are accelerated by temperature) they can be accelerated, inhibited or remain unaffected by pressure. Mere comparisons of treatments, a frequently published approach, do not allow calculation of the "reaction activation volume" constant. Reactions will be accelerated, inhibited or remain unaffected by pressure if this constant is negative, positive or zero. (2) Improved applications of food process engineering principles for safer/higher quality foods: Closely related to the development of new processing technologies is the need to develop new methodologies for an improved application of food process engineering principles. Moreover, calculations needed to support safe processing, packaging, and storage decisions should consider model parameter variability, a consideration rarely used by food processors reflecting a weakness in food science education. New procedures are now necessary to evaluate the impact of the variability in the parameters of food engineering models used for decisions of safe processing, packaging, storage and distribution conditions and must be taught in FST programs. The variability of these parameters generates an uncertainty in the estimations of product safety and quality submitted by food processors to regulatory agencies. Also, consumers and processors want to know the time that products will retain the quality desired and safety expected. These problems depend on factors described by statistical distributions requiring non-deterministic solutions such as the ones developed at OSU using Monte Carlo calculation procedures. PARTICIPANTS: Jorge Welti-Chanez, Professor and Dean Instituto Tecnologico y de Estudios Superiores de Monterrey, Mexico Gonzalo Velazquez, Graduate Program Coordinator Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Instituto Politecnico Nacional, Mexico Conchi Perez Lamela, Associate Professor Universidad de Vigo, Ourense campus, Spain TARGET AUDIENCES: Food processors and FST faculty and students PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
(1) New technologies: Some chemical reactions are greatly accelerated by pressure, while others can be inhibited to such a large content that in a typical PATP process there is not enough time for them to have an effect on food composition. While the latter explains to a large extent why PATP foods will be of much higher quality than conventional products, some reactions are accelerate by pressure. This is the case of the undesirable formation of aldehydes in PATP milk products. An additional consideration is the possibility that reactions leading to toxic compounds could also be accelerated in PATP foods. The unpredictable nature of reactions in PATP foods justifies the regulatory approach known as novel food laws and used by the European Union and Canada. Novel foods must introduce no new food safety risk and have similar retention of nutrients than equivalent conventional foods. To export PATP foods produced in the USA to these countries, the processor will need to demonstrate that they comply with these regulations in addition to be free of microbial pathogens. Several publications have been completed to show how reaction kinetics analysis can be used to accomplish this task. In addition, international research collaborations have been necessary to study the retention of vitamins and control of aldehyde in dairy products enriched with natural antioxidants. (2) Improved applications of food process engineering principles for safer/higher quality foods: Our Monte Carlo-based approach integrating engineering and statistics models, and its Excel implementation, has attracted international interest. Applications published and to be published soon include new recommendations to determine the microbial inactivation by HTST and retort thermal processing to meet new regulatory standards ensuring that all lots processed reach safety with 95% certainty. The assessment of food processing technologies and operating conditions has been based on the risk reduction (e.g., 5 decimal reductions in pathogens), or endpoint risk achieved (e.g., 1 surviving pathogen per billion containers). In spite of revisions, two undesirable regulatory defects remain: 1) the concentration causing an undesirable safety risk is assumed to be the same; and, 2) there is no distinction between gastrointestinal disorders and death risks. We completed an alternative assessment strategy demonstrated for high pressure processing (HPP) using a published Beta Poisson dose-response model correlating Vibrio vulnificus load with public health records to predict septicemia probability after ingesting raw oysters, a product of high importance in the Pacific NW. We included all sources of variability (V. vulnificus load in raw oysters, oyster weight, number of oysters consumed per serving, decimal reductions achieved by the HPP treatment, and variability of the dose-response function). Interestingly, the approach used to analyze product safety and quality is of general validity and has been applied also to estimate the shelf life of refrigerated meat products and dry vegetables and fruits.

Publications

• REFEREED JOURNAL ARTICLES, 2005 to 2010
• Almonacid-Merino SF, Torres JA. 2010. Uncertainty of microbial shelf-life estimations for refrigerated foods due to the experimental variability of the model parameters. Journal of Food Process Engineering 33(S1):66-84.
• Chotyakul N, Perez Lamela C, Torres JA. 2011. Effect of model parameter variability on the uncertainty of refrigerated microbial shelf-life estimates. Journal of Food Process Engineering (Accepted for Publication July 13, 2010): doi:10.1111/j.1745-4530.2010.00631.x
• Tirado J, Paredes D, Velazquez G, Torres JA. 2005. Microbial growth in refrigerated meat products. Ciencia y Tecnologia Alimentaria (Food Science & Technology, Spain) 5: 66-76.
• BOOK CHAPTERS, 2005 to 2010
• Jaczynski J, Chen Y-C, Rodrigo Garcia J, Velazquez G, Torres JA. 2009. Lipidos, proteinas y aminoacidos (Lipids, proteins and aminoacids). In Tecnologia de Productos de Origen Acuatico (Aquatic Food Technology), Volume I, Recursos Marinos y Utilizacion de Subproductos (Marine Resources and Utilization of Subproducts), Guerrero Legarreta, I., Rosmini, M.R., Armeneta Lopez, R.E. (editors), Editorial LIMUSA, S.A. de C.V. Mexico D.F.
• Jaczynski J, Chen Y-C, Velazquez G, Torres JA. 2009. Procesamiento de Productos Pesqueros con Haz de Electrones (Seafood processing by e-beam irradiation). In Tecnologia de Productos de Origen Acuatico (Aquatic Food Technology), Volume II, Tecnologia de Pescado y Mariscos (Shellfish and Seafood Technology), Guerrero Legarreta, I., Rosmini, M.R., Armeneta Lopez, R.E. (editors), Editorial LIMUSA, S.A. de C.V. Mexico D.F.
• Kongraksawech T, Vazquez-Landaverde P, Rodrigo-Garcia J, Torres JA, Huerta-Ruelas J. 2008. Optical techniques to determine thermal effects on proteins. International Journal of Food Science & Technology 43(11): 1922-1928.
• Ramirez R, Saraiva JA, Perez Lamela C, Torres JA. 2009. Reaction kinetics analysis of chemical changes in pressure-assisted thermal processing, PATP. Food Engineering Reviews 1:16-30.
• Huerta-Ruelas J, Lopez- Echevarria D, Mendoza-Sanchez P, Kongraksawech T, Torres JA. 2008. Optical rotation measurements in process control and engineering research in foods. Spanish Journal of Agricultural Research 6(4): 635-644
• Perez Lamela C, Torres JA. 2008. Pressure processing of foods: Part 1. An alternative for high flavour quality foods retaining health enhancing factors. AgroFOOD Industry Hi-Tech. 19 (3): 60-62.
• Perez Lamela C, Torres JA. 2008. Pressure processing of foods: Part 2. Microbial inactivation & chemical changes in pressure-assisted thermal processing (PATP). AgroFOOD Industry Hi-Tech. 19 (4): 34-36.
• Velazquez G, Miranda-Luna P, Lopez-Echevarria G, Vazquez M, Torres JA, Ramirez JA. 2008. Insoluble proteins recovered from surimi wash water of Pacific whiting as a functional additive for Alaska Pollock surimi gels. Journal of Texture Studies 39: 296-308.
• Paredes-Sabja D, Torres JA, Setlow P, Sarker MR. 2007. Clostridium perfringens spore germination: characterization of germinants and their receptors. Journal of Bacteriology 190 (4): 1190-1201.
• Vazquez-Landaverde PA, Qian MC, Torres JA. 2007. Kinetic analysis of volatile formation in milk subjected to pressure-assisted thermal treatments. Journal of Food Science 72: E389-E398.
• Paredes-Sabja D, Gonzalez M, Sarker MR, Torres JA. 2007. Combined effects of hydrostatic pressure, temperature and pH on the inactivation of spores of Clostridium perfringens type A and Clostridium sporogenes. Journal of Food Science 72 (6): M202-M206.
• Torres JA. 2006. Estrategias de control de la cadena de frio y su impacto en la calidad y seguridad de los alimentos (Strategies for the control of the food chain and its impact on food quality and safety). In Propiedades Fisicoquimicas y Sistemas de Procesado de Productos Hortofruticolas en el Desarrollo Agroalimentario (Physicochemical Properties & Processing Systems for Horticultural Products in the Development of the Agriculture & Food Sector), G. Salamanca Grosso (compiler), Ibague, Colombia.
• Paredes-Sabja DG, Morales-Blancas E, Ah-Hen KS, Velazquez G, Torres JA. 2008. Crecimiento microbiano durante la comercializacion de alimentos refrigerados. (Microbial growth during the commercial distribution of refrigerated foods). Capitulo 12. In Nuevas Perspectivas sobre Inocuidad Alimentaria (New Perspectives on Food Safety), Uresti-Marin RM, Ramirez de Leon JA, Vazquez- Vazquez M. (editores), Plaza y Valdes SACV, Mexico DF, Mexico.
• Torres JA, Velazquez G. 2008. Hydrostatic pressure processing of foods. In Food Processing Operations and Modeling, 2nd edition, J. Irudayaraj, S. Jin (editors), CRC Press Inc.
• Torres JA. 2006. Alta presion hidrostatica (APH): Una nueva tecnologia de alto valor agregado a frutos tropicales y subtropicales (High pressure processing (HPP): A new technology to add value to tropical and subtropical fruits). In Propiedades Fisicoquimicas y Sistemas de Procesado de Productos Hortofruticolas en el Desarrollo Agroalimentario (Physicochemical Properties & Processing Systems for Horticultural Products in the Development of the Agriculture & Food Sector), G. Salamanca Grosso (compiler), Ibague, Colombia.
• Torres, J.A., Chen, Y-C., Rodrigo Garcia, J., Jaczynski, J. 2006. Recovery of by-products from seafood processing waste streams. In Maximising the Value of Marine By-Products, F. Shahidi (editor), Woodhead Publishing Limited. Cambridge, UK.
• PUBLISHED PROCEEDINGS, 2005 to 2010
• Torres JA, Chotyakul N, Velazquez G, Saraiva JA & Perez Lamela C (2010) Integration of statistics and food process engineering: Assessing the uncertainty of thermal processing and shelf-life estimations. Actas del VI Congreso Espanol de Ingenieria de Alimentos (ISBN 978-84-7359-654-1), Logrono, La Rioja, Espana.
• Torres JA, Martinez Monteagudo SI, Leal Davila M, Saldana MDA & Welti Chanes J. 2010. Tecnologias de alta presion hidrostatica para la pasteurizacion y esterilizacion comercial de alimentos. Actas del VI Congreso Espanol de Ingenieria de Alimentos (ISBN 978-84-7359-654-1), Logrono, La Rioja, Espana.
• Velazquez G, Vazquez M, Torres JA. 2009. Procesamiento de Productos Pesqueros por Alta Presion Hidrostatica (Seafood processing by high hydrostatic pressure). In Tecnologia de Productos de Origen Acuatico (Aquatic Food Technology), Volume II, Tecnologia de Pescado y Mariscos (Shellfish and Seafood Technology), Guerrero Legarreta, I., Rosmini, M.R., Armeneta Lopez, R.E. (editors), Editorial LIMUSA, S.A. de C.V. Mexico D.F.
• Velazquez G, Vazquez-Landaverde PA, Torres JA. 2008. Consideraciones comerciales en la pasteurizacion de alimentos envasados y otras aplicaciones del procesamiento por alta presion hidrostatica. (Commercial considerations in the pasteurization of packaged foods and other applications of high hydrostatic pressure processing). Capitulo 10. In Nuevas Perspectivas sobre Inocuidad Alimentaria (New Perspectives on Food Safety), Uresti-Marin RM, Ramirez de Leon JA, Vazquez- Vazquez M. (editores), Plaza y Valdes SACV, Mexico DF, Mexico.
• Velazquez G, Vazquez-Landaverde PA, Torres JA. 2008. Retos tecnologicos en la pasteurizacion de alimentos por alta presion hidrostatica. (Technical challenges in the pasteurization of foods by high hydrostatic pressure processing). Capitulo 11. In Nuevas Perspectivas sobre Inocuidad Alimentaria (New Perspectives on Food Safety), Uresti-Marin RM, Ramirez de Leon JA, Vazquez- Vazquez M. (editores), Plaza y Valdes SACV, Mexico DF, Mexico.
• Torres JA. 2005. Avances y oportunidades comerciales para el procesamiento por altas presiones hidrostaticas, una tecnologia de punta instalada en Mexico (Advances and commercial opportunities for high hydrostatic pressure processing, a cutting-edge technology well established in Mexico). In Proceedings of the Ciclo de Conferencias Magistrales del Congreso de Ciencias del Instituto de Ciencias Biomedicas (Biomedical Sciences Institute Keynote Conferences in Science), Universidad Autonoma de Ciudad Juarez, Mexico, September 5-9, 2005.
• NON- REFEREED JOURNAL ARTICLES, 2005 to 2010
• Martinez Monteagudo SI, Leal Davila M, Saldana MDA, Torres JA & Welti Chanes J. 2010. Nuevas tecnologias para la industria de alimentos en Mexico utilizando la alta presion hidrostatica. Part 2. Industria Alimentaria 33(1): 44-50.
• Ulloa-Fuentes PA, Galotto MJ, Torres JA. 2008. Pressure-assisted thermal processing (PATP), the future of a new technology already installed in Mexico, Part I (Procesos termicos asistidos por presion (PTAP), el futuro de una nueva tecnologia ya instalada en Mexico - Parte I). Industria Alimentaria 30(3): 19-23.
• Martinez Monteagudo SI, Leal Davila M, Saldana MDA, Torres JA & Welti Chanes J. 2010. Nuevas tecnologias para la industria de alimentos en Mexico utilizando la alta presion hidrostatica. Part 1. Industria Alimentaria 32(6): 34-37.
• Perez Lamela C, Ramirez R, Lozano M, Cava Lopez R, Saraiva JA, Sanz P, Otero P, Torres JA. 2010. Una nueva red de investigadores en tecnologias de alta presion hidrostatica busca obtener alimentos de mejor calidad. Investigacion: Cultura, Ciencia y Tecnologia.
• Ulloa-Fuentes PA, Galotto MJ, Torres JA. 2008. Pressure-assisted thermal processing (PATP), the future of a new technology already installed in Mexico, Part II. (Procesos termicos asistidos por presion (PTAP), el futuro de una nueva tecnologia ya instalada en Mexico - Parte II). Industria Alimentaria 30(2): 20, 22, 24, 26, 28, 29.
• Mendoza-Sanchez P, Lopez D, Kongraksawech T, Vazquez P, Torres JA, Ramirez JA, Huerta-Ruelas J. 2005. Laser metrology in food related systems. In Proceedings of the Eighth International Symposium on Laser Metrology, vol. 5776, p. 347-354, International Society for Optical Engineering, R. Rodriguez-Vera, F. Mendoza-Santoyo (editors).
• Torres JA, Rios RA. 2006. Alta presion hidrostatica: Una tecnologia que irrumpira en Chile (High pressure technology: A technology emerging in Chile). Agro Economico, Febrero (Economic Agriculture, Chile, February): 40-43.
• Tirado J, Paredes D, Velazquez G, Torres JA. 2006. Control de la cadena de frio para productos carnicos refrigerados (Cold chain control for refrigerated meat products). Industria Alimentaria (Food Industry, Mexico) 28(2): 22-26
• Tirado J, Paredes D, Velazquez G, Torres JA. 2005. Optimice la cadena de frio para reducir riesgos microbiologicos y extender la vida util de productos carnicos refrigerados (Improve your cold chain to reduce microbial risks and extend the shelf life of refrigerated meat products). CARTANETIF 17, Septiembre-Octubre (September-October).
• Kongraksawech T, Vazquez P, Huerta-Ruelas J, Torres JA. 2007. Ionic strength and pH effects on optical thermographs for bovine serum albumin (BSA). Ciencia y Tecnologia Alimentaria (Food Science & Technology, Spain) 5(4): 259-264.
• Vazquez-Landaverde PA, Torres JA, Qian MC. 2006. Effect of high pressure-moderate temperature processing on the volatile profile of milk. Journal of Agricultural and Food Chemistry 54: 9184-9192.
• Vazquez-Landaverde PA, Torres JA, Qian MC. 2006. Quantification of trace volatile sulfur compounds in milk by solid-phase microextraction and gas chromatography-pulsed flame photometric detection. Journal of Dairy Science 89:2919-2927.

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: The number of commercial installations continues to increase at exponential rate while vessel size increased nearly a tenfold during the last 15 yrs. I am focusing on pressure-assisted thermal processing (PATP), i.e., simultaneous application of elevated pressure and temperature to preheated foods. Last April, the USA had the first regulatory approval for low-acid PATP-food in the world. However, quality while ensuring inactivation of bacterial spores requires substantially more research. A CAMPUS seminar "Toxicological risks & benefits of pressure-assisted thermal processing: Principles and reaction chemistry in foods at high pressure and high temperature" was presented Jan 6. An invited talk "Advantages & Toxicological Risks of Pressure-Assisted Thermal Processing" was presented Jan 28 at IOWA S U. On Feb 4, I presented "Food, more much more than what is on your plate" in the CAMPUS -course ES 399/599. My collaboration with Spain covering "Chemical changes when seeking fuller utilization of seafood resources by high pressure processing" was presented at the Feb 26 PORTLAND meeting on "A sustainable Future: Fish Processing Byproducts." My collaborator in Portugal presented "Chemical changes in foods processed by pressure-assisted thermal processing (PATP)" during the Apr 16-17 "COST Action 927" Annual Meeting held in PORTUGAL. This very large European project focuses on toxic chemicals formed when heating foods. An invited talk "High pressure and pressure-assisted thermal processing of milk: Analysis of chemical changes during pasteurization and sterilization treatments" was presented at the IFT symposium (Jun 6-10, ANAHEIM, CA) "Emerging Technologies and Dairy: from Microbial Inactivation to Novel Functionality". An Oct 6-7 visit to U FLORIDA pressure research facilities included another PATP talk. Finally, an invited short course entitled "Principles and Quality of Pressure Processing Technologies for the Pasteurization and Sterilization of Foods" was presented at the "Postharvest and Processing Technologies" Workshop held Oct 14-16 in SPAIN and at the 4th International Meeting on Food Science Research and Education held Nov 24-27 in MEXICO. The same course was presented remotely Dec 16-17 in ARGENTINA. Other diffusion activities included the meeting of NC-1023, Improvement of Thermal and Alternative Processes for Foods held in HOUSTON, TX. I am an active collaborator with international pressure processing technology researchers co-advising two graduate students at U of Alberta who will come to OSU and analyze their experimental findings on a novel PATP technology for milk high in conjugated linoleic acid content. I organized in Spain two meetings attended by nearly 20 researchers from USA, Spain and Portugal. An OSU PhD student under my co-supervision will develop a novel PATP technology for milk enriched with natural antioxidants. The goal is to reverse the decline in milk consumption among young consumers with a product with improved taste and enriched with desirable nutrients. In summary, research was disseminated locally, nationally and internationally to Canada, Mexico, Argentina and Europe. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The outcomes of research and dissemination activities include: (1) CONTRIBUTION TO THE ELIMINATION OF TECHNICAL MISCONCEPTIONS. These have been caused by the rapid development and commercialization of pressure technologies (please note that over 50% of commercial users are located in the USA and one of the two largest producers of industrial units is located in the Northwest). Among these technical errors has been the development of pressure processes in pilot plants operating at room temperature while most pressure processors operate at refrigeration temperature (e.g., Toby's Family Foods, Springfield, OR). This causes an overestimation processing times since refrigeration temperature accelerates microbial inactivation. A serious misapplication of science is the almost universal use of the Le Chatelier principle to explain the benefits of pressure processing technologies. This principle is valid only when analyzing food systems under equilibrium. Therefore, they cannot be analyzed dynamic processing and storage conditions. Processors do not subject to foods to treatments reaching equilibrium damage nor will they store products until they reach equilibrium spoilage. In the case of PATP products, it will be necessary to consider during their treatment changes in the temperature profile of the food and its surrounding pressurizing fluid. These changes will affect the inactivation of microorganisms and enzymes as well as the changes in the chemical composition of foods. Plans are to develop a manual of good practices for the development and implementation of pressure processing technologies. (2) IMPACT OF THE UNCERTAINTY IN MODEL PARAMETERS ON ESTIMATIONS OF PROCESSING PARAMETERS AND SHELF-LIFE OF FOODS. Food regulatory agencies in the USA and elsewhere are beginning to require estimations of confidence in the decisions taken by food processors. Two examples were analyzed and submitted for publication: thermal processing of foods and microbial shelf-life of refrigerated foods. Findings from this research will be incorporated when teaching FST 490/590 Food Processing Calculations. (3) CHEMICAL REACTIONS UNDER NOVEL PROCESSING TECHNOLOGIES. The combination of high pressure and high temperature offers unique commercial opportunities for new foods if we can demonstrate process safety and effectiveness. US-based research has focused on microbial safety while novel foods laws common in other markets (e.g., Canada and Europe) but not in the USA require an examination of nutrient retention and potential formation of toxic compounds in novel foods. In my presentations, I have pointed out the scarcity of information on chemical changes in foods under high pressure and high temperature, and the total absence of studies on the potential formation of toxic compounds in these foods (e.g., acrylamide in potato products).

Publications

• Torres JA, Sanz P, Otero L, Perez Lamela C, Saldana MDA. 2009. Temperature distribution and chemical reactions in foods treated by pressure-assisted thermal processing. In Processing Effects on Safety and Quality of Foods, Chapter 14, p. 379-414, Ortega-Rivas E (editor), CRC Taylor & Francis, London.
• Paredes-Sabja D, Torres JA. 2010. Modeling of the germination of spores from Clostridium perfringens food poisoning isolates. Journal of Food Process Engineering. IN PRESS (Accepted August 2008).
• Torres JA, Sanz P, Otero L, Perez Lamela C, Saldana MDA. 2009. Engineering principles to improve food quality and safety by high pressure processing. In Processing Effects on Safety and Quality of Foods, Chapter 15, p. 415-440, Ortega-Rivas E (editor), CRC Taylor & Francis, London.
• Ramirez R, Torres JA. 2009. Chemical and quality changes when seeking fuller utilization of seafood resources by pressure processing technologies. In A sustainable future: Fish processing byproducts. Alaska Sea Grant, University of Alaska, Fairbanks, AK, P. Bechtel, S. Smiley (editors).
• Almonacid SF, Torres JA. 2010. Uncertainty of microbial shelf-life estimations for refrigerated foods because of the experimental variability of the model parameters. Journal of Food Process Engineering. IN PRESS (Accepted April 2008).
• Ramirez R, Saraiva JA, Perez Lamela C, Torres JA. 2009. Reaction kinetics analysis of chemical changes in pressure-assisted thermal processing, PATP. Food Engineering Reviews 1:16-30.
• Rodrigo Garcia J, Jaczynski J, Torres JA. 2009. Utilization and protein recovery from surimi processing water. In A sustainable future: Fish processing byproducts. Alaska Sea Grant, University of Alaska, Fairbanks, AK, P. Bechtel, S. Smiley (editors).
• Akhtar S, Paredes-Sabja D, Torres JA, Sarker MR. 2009. Strategy to inactivate Clostridium perfringens spores in meat products. Food Microbiol 26(3): 272-277.

Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: My 2008 research output can be separated into three areas: (1) New processes and products; (2) High pressure/High temperature inactivation of bacterial spores; and (3) Chemical reactions in foods under high pressure and high temperature. An invited seminar entitled "Quality of pressure-treated food products" was presented in the Session on the Status of the Application and Commercialization of Nonthermal Processing Technologies organized by the Institute of Food Technologists at the Nonthermal Processing Workshop held January 13-16 in Portland, OR. Results from an international collaboration with Chile focusing on pressure effects on packaging materials were also presented at this meeting. Two invited seminars on the status of pressure-assisted thermal processing technologies for shelf stable dairy products were also accepted. One was presented at the Annual Meeting of the Western Dairy Center, held May 6 in Logan, UT, and the other one was at the Department of Food Science, Cornell U, held September 5, 2008, in Ithaca, NY. Attendance to the meeting of NC-1023, Improvement of Thermal and Alternative Processes for Foods held in Knoxville, TN, and research meetings in Pullman, WA resulted in a joint proposal to be submitted with Washington State and Iowa State University in 2009. Results from an international project on pressure treated berries with Mexico were presented by my collaborators at the III International Congress on Food Science and Food Biotechnology in Developing Countries held October 14-17 in Queretaro, Mexico. All results from this research were part of a graduate thesis defense that I attended as an international committee member and held November 28 in Queretaro, Mexico. I am an active collaborator with European researchers working in pressure processing technologies. During an October 15 to November 3 visit, I presented seminars on pressure assisted thermal processing focusing on the formation risk of toxic chemicals at the U of Vigo (Galicia, Spain)and on pressure processing commercialization at the Technological Institute of Agriculture and Food (Extremadura, Spain). In addition, I visited industrial users of pressure processing technologies utilizing units produced in the Northwest, and examined research vessels produced in Poland, Spain and Great Britain used by my research colleagues. Most importantly, I organized a meeting attended by 15 researchers from USA, Spain and Portugal to identify fundable research collaborations which resulted in plans for the submission of four funding requests. I am also an active collaborator with Canada's U of Alberta and developed a joint research proposal on a novel processing technologies for dairy beverages high in conjugated linoleic acid (CLA) enriched with natural antioxidants. In summary, research was disseminated nationally and internationally to Canada, Mexico, Chile and Europe. PARTICIPANTS: OSU collaborators: Mahfuz Sarker, Robert Durst US collaborators: Gustavo Barbosa Canovas at Washington State University ([e-mail]), Stephanie Jung ([e-mail]) International collaborators: Marleny Aranda Saldana (Canada, U of Alberta, [e-mail]), Gonzalo Velazquez (Mexico, U A Tamaulipas, [e-mail]), Edmundo Mercado (Mexico, U A Queretaro, [e-mail]), Jorge Saraiva (Portugal, U Aveiro [e-mail]), Rosario Ramirez Bernabe (Spain, Technological Institute of Agriculture and Food of Extremadura, [e-mail]), Concepcion Perez (Spain, U Vigo, [e-mail]), Lorenzo Pastrana (Spain, U Vigo, [e-mail]), Pedro Sanz (Spain, Consejo Superior de Investigaciones Cientificas-CSIC, [e-mail]), Laura Otero (Spain, Consejo Superior de Investigaciones Cientificas-CSIC [e-mail]), Antonio Molina (Spain, Consejo Superior de Investigaciones Cientificas-CSIC, [e-mail]), Maria Jose Galotto (Chile, U Santiago de Chile, [e-mail]) TARGET AUDIENCES: One of the first research programs in the nation on the commercialization of high pressure processing (HPP) begun in the early 1990's at Oregon State University (Torres, Farkas) with a still-ongoing collaboration with Avure Technologies (Kent, WA). Early research focused on microbial inactivation, novel applications and product formulation principles. New units will allow the commercial implementation of pressure-assisted thermal processing (PATP), i.e., the simultaneous application of elevated pressure and temperature to preheated foods for the sterilization of low-acid foods. A PATP-sterilization process for mashed potatoes is under FDA review and could become the world's first PATP-sterilized product. The current challenge is that we do not have a full understanding of PATP effects on microorganisms and nothing has been published on the chemical changes that PATP processing can induce in foods, including the potential formation of acrylamide and other toxicants. This information is needed by industry and both current and future researchers in the USA and elsewhere need to become aware of this need including the role of the food matrix, dissolved oxygen, native and added natural antioxidants on the degradation of nutrients and potential formation of toxic compounds. PATP foods must be subjected to the Ames, Comet and similar rapid tests to reduce the likelihood of exposing consumers to unknown risks. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The outcomes of research and dissemination activities include: (1) CONTRIBUTION TO THE ELIMINATION OF TECHNICAL MISCONCEPTIONS. These have been caused by the rapid development and commercialization of pressure technologies (please note that over 50% of commercial users are located in the USA and the largest producer of industrial units is located in the Northwest). Among these technical errors has been the development of pressure processes in pilot plants operating at room temperature while most pressure processors operate at refrigeration temperature (e.g., Toby's Family Foods, Springfield, OR). This causes an overestimation processing times since refrigeration temperature accelerates microbial inactivation. (2) SPORE INACTIVATION MECHANISMS. Collaborations with Dr M. Sarker at OSU are focusing on the molecular mechanisms of spore germination, particularly of Clostridium perfringens spores which are the third cause of bacterial food poisoning in the USA. This knowledge is being used to develop combine novel/conventional technologies for shelf stable low acid foods. (3) CHEMICAL REACTIONS UNDER NOVEL PROCESSING TECHNOLOGIES. The combination of high pressure and high temperature offers unique commercial opportunities for new foods if we can demonstrate process safety and effectiveness. US-based research has focused on microbial safety while novel foods laws common in other markets (e.g., Canada and Europe) but not in the USA require an examination of nutrient retention and potential formation of toxic compounds in novel foods. In my presentations, I have pointed out the scarcity of information on chemical changes in foods under high pressure and high temperature, and the total absence of studies on the potential formation of toxic compounds in these foods (e.g., acrylamide in potato products).

Publications

• Velazquez G, Vazquez-Landaverde PA, Torres JA. 2008. Commercial considerations in the pasteurization of packaged foods and other applications of high hydrostatic pressure processing. Chapter 10. In New Perspectives on Food Safety, Uresti-Marin RM, Ramirez de Leon JA, Vazquez-Vazquez M. (editors), Plaza y Valdes SACV, Mexico DF, Mexico.
• Velazquez G, Vazquez-Landaverde PA, Torres JA. 2008. Technical challenges in the pasteurization of foods by high hydrostatic pressure processing. Chapter 11. In New Perspectives on Food Safety, Uresti-Marin RM, Ramirez de Leon JA, Vazquez-Vazquez M. (editors), Plaza y Valdes SACV, Mexico DF, Mexico.
• Perez Lamela C, Torres JA. 2008. Pressure processing of foods: Part 1. An alternative for high flavour quality foods retaining health enhancing factors. AgroFOOD Industry Hi-Tech. 19 (3): 60-62.
• Perez Lamela C, Torres JA. 2008. Pressure processing of foods: Part 2. Microbial inactivation & chemical changes in pressure-assisted thermal processing (PATP). AgroFOOD Industry Hi-Tech. 19 (4): 34-36.
• Paredes-Sabja D, Raju D, Torres JA, Sarker MR. 2008. Role of small, acid-soluble spore proteins in the resistance of Clostridium perfringens spores to chemicals. International Journal of Food Microbiology 122: 333-335.
• Ulloa-Fuentes PA, Galotto MJ, Torres JA. 2008. Pressure-assisted thermal processing (PATP), the future of a new technology already installed in Mexico, Part II. Industria Alimentaria 30(2): 20, 22, 24, 26, 28, 29.
• Ulloa-Fuentes PA, Galotto MJ, Torres JA. 2008. Pressure-assisted thermal processing (PATP), the future of a new technology already installed in Mexico, Part I. Industria Alimentaria 30(3): 19-23.

Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: Pressure-assisted thermal processing (PATP) is expected to yield foods of much higher quality than conventional thermal processes. A goal of PATP treatments is to increase the shelf-life of pasteurized refrigerated foods up to 300% while retaining the quality of conventional pasteurization. This was demonstrated experimentally for milk flavor quality; however, the findings can be extrapolated to all foods for two reasons. First, the 27 compounds studied in milk represent many chemical reactions. In addition, temperature and pressure effects on the formation of these compounds were consistent with a general model for temperature and pressure effects on reaction kinetics. The independent calculation of activation energy and activation volume constants showed consistently that most reactions were inhibited by high pressure. These constants are derived from the general principle that a reactant passes through an "activated" state before forming the reaction product. Reactions with negative activation volume values were accelerated by pressure and their activation energy values decreased with pressure. The opposite behavior was observed for reactions with positive activation volume values, while no pressure effects on quality degradation reflected reactions with zero activation volume. Most interesting was the observation that most of the 27 compounds were not formed during PATP treatments. This means that these reactions had very large positive activation volume values and thus their rate of reaction during PATP treatments was so small that these compounds were formed only at undetectably small amounts. A further goal of PATP technology research is to sterilize foods. The severity of the treatment, and thus the cost of the process, could be lowered if we could induce the germination of bacterial spores. Once a spore has germinated, its resistance to pressure and heat is lost and can be inactivated by less severe heat and pressure treatments. Unfortunately, not much is known about germinants and how the rate of germination is affected by factors such as chemical nature of the germinant, pH, ionic strength, temperature, etc. This information is being generated for the case of Clostridium perfringens type A spores which are the third cause of food poisoning in the US. A predictive germination model for C. perfringens type A food poisoning isolates described well the germination in laboratory media of 4 C. perfringens type A food poisoning isolates, failing on the safe side, that is, over-predicting germination, for only one isolate. However, to predict C. perfringens germination more confidently, the experimental data needed to construct the germination model should be obtained using as samples the food of interest. This is important as the bioavailability of the germinants is likely to affect the germination response. To promote the commercialization of HPP and PATP technology, two peer-reviewed publications and two book chapters were completed, invitations to international conferences offered in Mexico, Chile, Spain, Germany and Belgium were accepted, and an international two-day workshop was offered in Spain. PARTICIPANTS: Dr. Mahfuz Sarker, Dept of Biomedical Sciences and Microbiology, Oregon State University; Dr. Gonzalo Velazquez, Unidad Academica Multidisciplinaria Reynosa-Aztlan, Universidad Autonoma de Tamaulipas, Mexico; Dr. Michael Qian, Dept. of Food Science & Technology, Oregon State University and Dr. Pedro Vazquez-Landaverde (PhD graduate from Dept. of Food Science & Technology, Oregon State University), Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Queretaro, Mexico. TARGET AUDIENCES: The audience reached includes peers to ensure by peer-evaluation of our publications that the research at OSU meets high quality standards. Also important are international visits to learn of research progress outside the US, international presentations -including organizing a two-day workshop in Spain- to promote high pressure processing technology being developed in the US, and participation at the international workshop on non-thermal processing alternatives to be held January 13-16, 2008 in Portland, Oregon.

Impacts
High pressure processing (HPP) has found many commercial applications in the world because pressure alone does not affect covalent bonds and thus the chemical composition of foods is not affected. This means that the quality of HPP-treated foods is close to that of unprocessed foods while ensuring their safety. Furthermore, pressure effects are almost instantaneous and independent of vessel and product geometry factors. This made the use of laboratory findings to develop industrial applications a very simple scale-up process which is not the case of thermal processing. The recent failure of the pulsed electric field (PEF) technology used by Genesis Juice Co-op in Eugene, Oregon, to inactivate pathogens in organic juices as required by FDA, shows the difficulties of most technologies in scaling up laboratory findings to commercial processing conditions. This leaves HPP as the only viable alternative for commercial pasteurization without using thermal treatments that cause destruction of nutrients and lowering of sensory quality. PATP is not yet a commercial application and will require more complex safety validation procedures than HPP because it will require careful analysis of heat transfer and compression heating. Future collaboration with a research group in Madrid will facilitate research efforts in this area.

Publications

• Torres JA, Velazquez G. 2007. Hydrostatic pressure processing of foods. In Food Processing Operations and Modeling, 2nd edition, J. Irudayaraj, S. Jin (editors), CRC Press Inc.
• Paredes-Sabja D, Torres JA, Setlow P, Sarker MR. 2007. Clostridium perfringens spore germination: characterization of germinants and their receptors. Journal of Bacteriology (available on line).
• Vazquez-Landaverde PA, Qian MC, Torres JA. 2007. Kinetic analysis of volatile formation in milk subjected to pressure-assisted thermal treatments. Journal of Food Science 72: E389-E398.
• Paredes-Sabja D, Gonzalez M, Sarker MR, Torres JA. 2007. Combined effects of hydrostatic pressure, temperature and pH on the inactivation of spores of Clostridium perfringens type A and Clostridium sporogenes. Journal of Food Science 72 (6): M202-M206.

Progress 01/01/06 to 12/31/06

Outputs
OUTPUTS: In previous years, we reported that pressure-assisted thermal processing (PATP) treatments (e.g., 586 MPa for 3 and 5 min) at moderate temperature (55C or 130F) can extend the refrigerated shelf life of milk to over 45 d. Most importantly, these moderate PATP treatments yield milk with similar flavor volatile profile to that of conventionally pasteurized milk. This year we completed a kinetic analysis for 27 volatiles reported in the literature as reflecting the impact of thermal treatments on the flavor quality of milk. Our interpretation of the formation of volatiles in milk on the basis of temperature and pressure effects on their kinetic constant (k) uses the energy of activation and activation volume models. These models assume that the conversion of a reactant into a milk volatile passes through an "activated" state. The activation energy needed to reach the activated state is always a positive value, whereas activation volume values defined as the difference between the partial molar volumes of the activated state and the partial volumes of the reactants can be negative, positive or zero. Reactions with activation energy decreasing with pressure will be consistent with an increased volatile formation in PATP-milk as compared to conventional thermal treatments. Moreover, these reactions will have negative activation volume values and thus k-values at constant temperature will increase with pressure. The opposite behavior will be observed for reactions with activation energy values increasing with pressure, while no pressure effects on activation energy values correspond to reactions with zero activation volume. For reactions with very large positive activation volume values, the reaction kinetic constants at high pressure would be so small that volatile formation would not be observed during PATP treatments. To promote the commercialization of HPP and PATP, three peer-reviewed publications and two book chapters were completed, and invitations to four international conferences offered in Mexico, Colombia and Chile were accepted. PARTICIPANTS: Dr. Gonzalo Velazquez, Unidad Academica Multidisciplinaria Reynosa-Aztlan, Universidad Autonoma de Tamaulipas, Mexico; Dr. Michael Qian, Dept. of Food Science & Technology, Oregon State University and Dr. Pedro Vazquez-Landaverde (PhD graduate from Dept. of Food Science & Technology, Oregon State University), Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Queretaro, Mexico.

Impacts
We concluded that pressure inhibits most thermal degradation reactions in milk. The diversity of chemical reactions associated with the production of these 27 volatiles suggests that this may be true in food products other than milk. It should be noted that PATP is not yet a commercial application and that it will require more complex safety validation procedures than high pressure processing (HPP). In our analysis of PATP-milk, the increase, decrease or lack of change caused by pressure and temperature on the formation of milk volatiles was explained with no need to assume alternative reaction pathways. PATP promoted the formation of few compounds, had no effect on some and inhibited the formation of most volatiles reported to be factors of the consumer rejection of "cooked" milk flavor. New reaction formation mechanisms were not likely involved in volatile formation in PATP-milk. Finally, the application of the Le Chatelier principle frequently used to explain the high quality of pressure-treated foods, often with no supporting experimental evidence, was not necessary.

Publications

• Torres JA. 2006. Alta presion hidrostatica (APH): Una nueva tecnologia de alto valor agregado a frutos tropicales y subtropicales (High pressure processing (HPP): A new technology to add value to tropical and subtropical fruits). In Propiedades Fisicoquimicas y Sistemas de Procesado de Productos Hortofruticolas en el Desarrollo Agroalimentario (Physicochemical Properties & Processing Systems for Horticultural Products in the Development of the Agriculture & Food Sector), G. Salamanca Grosso (compiler), Ibague, Colombia.
• Velazquez G, Vazquez M, Torres JA. 2006. Procesamiento de Productos Pesqueros por Alta Presion Hidrostatica (Seafood processing by high hydrostatic pressure). In Tecnologia de Productos de Origen Acuatico (Aquatic Food Technology), Volume II, Tecnologia de Pescado y Mariscos (Shellfish and Seafood Technology), Guerrero Legarreta, I., Rosmini, M.R., Armeneta Lopez, R.E. (editors), Editorial LIMUSA, S.A. de C.V. Mexico D.F.
• Vazquez-Landaverde PA, Torres JA, Qian MC. 2006. Effect of high pressure-moderate temperature processing on the volatile profile of milk. Journal of Agricultural and Food Chemistry 54: 9184-9192.
• Vazquez-Landaverde PA, Torres JA, Qian MC. 2006. Quantification of trace volatile sulfur compounds in milk by solid-phase microextraction and gas chromatography-pulsed flame photometric detection. Journal of Dairy Science 89:2919-2927.