Effects of Ionizing Radiation on Pork, Beef, and Turkey Quality Kevin Eugene Nanke Iowa State University

Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1998 Effects of ionizing radiation on pork, beef, and turkey quality Kevin Eugene Nanke Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Agriculture Commons, and the Food Science Commons Recommended Citation Nanke, Kevin Eugene, "Effects of ionizing radiation on pork, beef, and turkey quality " (1998). Retrospective Theses and Dissertations. 11877. https://lib.dr.iastate.edu/rtd/11877 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. 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TJMI Number: 9841072 Copyright 1998 by Nanke, Kevin Eugene All rights reserved. UNC Microform 9841072 Copyright 1998, by UMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 11 Graduate College Iowa State University This is to certify that the Doctoral dissertation of Kevin Eugene Nanke has met the dissertation requirements of Iowa State University Signature was redacted for privacy. CcCommittee Member Signature was redacted for privacy. Committee Member Signature was redacted for privacy. Committee Member Signature was redacted for privacy. Co-major Professor Signature was redacted for privacy. -o-major Professor Signature was redacted for privacy. For the Cqmajor Program Signature was redacted for privacy. For the Co-major Program Signature was redacted for privacy. For the Graduate College m This dissertation is dedicated to my wife, Kathy, and son, Grant. Their love and support made this journey possible. iv TABLE OF CONTENTS ABSTRACT vii CHAPTER L INTRODUCTION 1 Introduction 1 Dissertation organization 3 CHAPTER 2. GENERAL REVIEW OF LITERATURE 5 Food Irradiation 5 History of development 6 Status of food irradiation 8 Consumer acceptance 9 Technical Aspects of Inadiation 12 What is irradiation? 12 Dose and dose rate 13 Radiation Sources for Food Irradiation 15 Sources applicable to food irradiation 15 Characteristics of radiation sources 16 Chemical Effects of Ionization Radiation 21 Primary and secondary effects 23 Effects of Irradiation on Food Components 25 Carbohydrates 25 Proteins 26 Lipids 26 Vitamins 27 Effects of Irradiation on Microorganisms 28 Theory and mechanisms of microbial reduction 30 Bacterial survival curves 32 Factors which influence microorganism survival 33 Irradiation Reduction of Microorganisms 37 Spoilage organisms 37 Irradiation increases the shelf-life of meat 38 Pathogenic organisms 41 Foodbome parasites 46 Foodbome yeast and mold 47 Foodbome viruses 47 Detection of Irradiated Foods 48 Myoglobin 51 Color of fresh meat 51 Factors which effect the discoloration of fresh meat 56 Muscle Fiber Types 64 V Irradiation and muscle fiber type 67 Effects of Irradiation on Myoglobin 68 Effects of Irradiation on Meat Quality Parameters 74 Color of irradiated meat 74 Odor of irradiated meat 79 Flavor of irradiated meat 81 References 83 CHAPTER 3. COLOR CHARACTERISTICS OF IRRADIATED VACUUM-PACKAGED PORK, BEEF, AND TURKEY 95 Abstract 95 Introduction 96 Materials & Methods 97 Sample preparation 97 Irradiation processing 98 Display characteristics 99 Color analysis 100 Visual color evaluation 101 Statistical analysis 102 Results & Discussion 102 Irradiation dosage 102 Instrumental color measurements 103 Visual color measurements 109 Conclusions 110 References Ill Acknowledgments 114 CHAPTER 4. COLOR CHARACTERISTICS OF IRRADIATED AEROBICALLY-PACKAGED PORK, BEEF, AND TURKEY 129 Abstract 129 Introduction 130 Materials & Methods 132 Sample preparation 132 Irradiation processing 133 Display characteristics 134 Color analysis 135 Visual color evaluation 136 Statistical analysis 137 Results & Discussion 137 Instrumental color measurements 137 Visual color measurements 146 Conclusions 147 vi References 148 Acknowledgments 152 CHAPTER 5. COLOR CHARACTERISTICS OF IRRADIATED PORK BICEPS FEMORIS, SEMITENDINOSUS, AND SEMIMEMBRANOSUS MUSCLE 168 Abstract 168 Introduction 169 Materials & Methods 170 Sample preparation 170 Irradiation processing 171 Color analysis 172 Myoglobin concentration 172 Statistical analysis 173 Results & Discussion 173 Irradiation dose 173 Instrumental color measurements 173 Conclusions 180 References 180 Acknowledgments 182 GENERAL SUMMARY 196 ACKNOWLEDGEMENTS 199 vii ABSTRACT Color changes observed in irradiated meat were found to be species- and package-type dependent. Irradiated vacuum-packaged (VP) pork and turkey became redder following to irradiation relative to unirradiated controls. However, irradiated VP beef decreased in redness as compared to unirradiated controls. In contrast, aerobically-packaged (AP) pork and beef became less red as a result of irradiation compared to unirradiated controls. Whereas, redness values of irradiated AP turkey increased due to irradiation. Redness values of the VP pork and turkey were unchanged during 12 and 10 wks, respectively, of display, but decreased for VP beef and all AP samples during display. Visual evaluation also indicated that VP pork and turkey and AP turkey increased in redness compared to VP beef and AP pork and beef, which decreased as dose levels increased. The surface color of irradiated VP and AP pork became less uniform at 3.0 and 4.5 kGy than unirradiated pork. The reflectance spectra showed that irradiation induced an oxymyoglobin-like pigment in VP pork. Irradiated VP beef developed a pigment which contained both oxymyoglobin-like and metmyoglobin-like pigments. The reflectance spectra of VP and AP turkey were relatively unaffected by increasing doses of irradiation. Porcine biceps femoris (BF), light and dark region of the semitendinosus (LST and DST), and semimembranosus (SMB) were packaged in VP or AP packaging and irradiated. BF, LST, and SMB had a hematin concentration of 27.5, 31.0, and 40.8 ppm, respectively. These muscle types increased similarly in magnitude following irradiation. Whereas, AP BF, LST, SMB, DST, and VP DST decreased in redness as a result of low-dose irradiation. Yellowness values for AP samples decreased but increased for VP samples with the exception of VP DST, which decreased. Reflectance specu'a indicated that metmyoglobin- like and oxymyoglobin-like pigments developed in irradiated AP and VP BF and LST samples, respectively. Aerobically-packaged and VP SMB samples were relatively unchanged by irradiation. A metmyoglobin-like pigment of similar reflectance developed in both AP and VP Vlll DST samples. The extent of irradiation-induced color changes in fresh meat appears to be independent of myoglobin concentration. 1 CHAPTER 1. GENERAL INTRODUCTION Introductioo Irradiation is not a new technology, but a technology that has regained momenttim in recent years. Research has proven that irradiation is an effective processing tool to eliminate or reduce pathogenic and spoilage organisms from meat. The process of applying ionizing energy to "cold pasteurize" fresh meat could potentially increase the cash receipts for producers, processors, and retailers. Irradiation will dramatically increase the safety and shelf-life of fresh meat. However, the color of fresh meat could be significantly affected by irradiation. The conditions and color changes in fresh meat induced by irradiation are not well understood. Kropf (1980)

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