PRINCIPLES OF
`ASEPTIC-
`PROCESSING
`AND PACKAGING
`
`edited by
`James V. Chambers
`Philip E. Nelson
`
`Department of Food Science
`Purdue University
`
`Fll
`The Food Processors Institute
`© 1993
`
`p. E1
`
`

`

`PRINCIPLES OF
`
`ASEPTIC PROCESSING
`
`AND PACKAGING
`
`p. E2
`
`

`

`Copyright © 1993 The Food Processors Institute
`Washington, D.C.
`
`All rights reserved. No part of this book may be reproduced or altered or utilized in any form or by any m1
`electronic or mechanical, including photocopying, recording or by any information storage and retrieval sy~
`without permission in writing from the copyright owner. Inquiries should be addressed to The Food Proce:
`Institute, 1401 New York Ave., N.W., Washington, D.C. 20005.
`
`Printed in the United States of America
`
`While the recommendations in this publication are based on scientific studies and wide industry experi<
`references to operating procedures and methods or types of instruments and equipment are not to be consl
`as a guarantee that they are sufficient to prevent damage, spoilage, loss, accidents or injuries, resulting fron
`of this information. Furthermore, the study and use of this publication by any person or company is n1
`assurance that a person or company is proficient in the operations and procedures discussed in this publica
`The use of the statements, recommendations, or suggestions contained, herein, is not to be considered as ere
`any responsibility for damage, spoilage, loss, accident or injury, resulting from such use.
`
`LIBRARY OF CONGRESS
`CATALOG CARD NO.: 93-071279
`
`The Food Processors Institute
`Principles of Aseptic Processing and Packaging.
`
`Washington, D.C.: Food Processors
`Institute, The
`
`257 p.
`
`ISBN 0-937774-03-0
`
`p. E3
`
`

`

`PRINCIPLES OF
`ASEPTIC PROCESSING
`AND PACKAGING
`
`edited by
`James V. Chambers
`Philip E. Nelson
`
`Contributors
`
`George Arndt
`Pet, Inc., St. Louis, MO
`
`Dane T. Bernard
`National Food Processors Association, Washington, D.C.
`
`James V. Chambers
`Purdue University, West Lafayette, IN
`
`Dilip I. Chandarana
`National Food Processors Association, Washington, D.C.
`
`M.A. Cousin
`Purdue University, West Lafayette, IN
`
`John D. Floros
`Purdue University, West Lafayette, IN
`
`Austin Gavin
`National Food Processors Association, Washington, D.C.
`
`Jack R. Giacin
`Michigan State University, East Lansing, MI
`
`Lloyd R. Hontz
`National Food Processors Association, Washington, D.C.
`
`Daryl B. Lund
`University of Wisconsin-Madison, Madison, WI
`
`Joseph E. Marcy
`Virginia Polytechnical Institute and State University, Blacksburg, VA
`
`(continued)
`
`iii
`
`~ans, 1
`;tern,';
`ssors
`
`!nee,
`trued
`1 use
`)( an
`1tion.
`ating
`
`p. E4
`
`

`

`Philip E. Nelson
`Purdue University, West Lafayette, IN
`
`S. Suzanne Nielsen
`Purdue University, West Lafayette, IN
`
`George D. Sadler
`National Center for Food Safety and Technology, Summit-Argo, IL
`
`Virginia N. Scott
`National Food Processors Association, Washington, D.C.
`
`Brad Shafer
`National Food Processors Association, Dublin, CA
`
`Rakesh K. Singh
`Purdue University, West Lafayette, IN
`
`iv
`
`p. E5
`
`

`

`TABLE OF CONTENTS
`
`Chapter 1 - Introduction
`Aseptic Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
`Microbiological Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
`The Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
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`Chapter 2 - The System and Its Elements
`Introduction
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0
`• 3
`• 4
`Basic Principles . . . . . . . . . . . . . 0
`Thermalbacteriology
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
`Heat Transfer . . . . . . . . . . . . . . 0
`• 6
`Heat Transfer Coefficients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
`Batch Systems
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
`• 11
`Continuous Systems . . . 0
`Velocity Distribution
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
`Thermal Process Calculation
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
`Processing Particulates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
`Thermal Process Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
`Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
`Characteristics of Specific Elements
`. . 0
`• 22
`Flow Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
`Heat Transfer/Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 22
`Direct Heating/Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
`• 23
`Indirect Heating/Cooling . . . . . . . . . . . . . . . . . . . . . . . . 0
`Hold Tube
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
`Daerators
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
`Aseptic Surge Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
`• 28
`References
`• 30
`Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . . 0
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`Chapter 3 - Residence Time Distribution in Aseptic Processing
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
`Introduction
`Mean Residence Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . · 31
`F(t) - Curves for Various Flow Patterns .... 0
`• 32
`Laminar Flow
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
`Plug Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
`• 33
`Continuous Stirred Tank Reactor (CSTR) ... o
`• 33
`Channeling
`. . . . . . . . . . . 0
`Dead Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
`E(t) Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
`• 34
`E(t) Curves for Various Types of Flows ....... 0
`Laminar Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
`• 34
`Plug Flow
`. . . . . . . . . . . . . . . . 0
`CSTR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
`Channeling . . . . . . . . . . . . 0
`• 34
`Dead Space
`. . . . . . . 0
`• 35
`Reduced Time (9) ....................................... 35
`• 36
`Comparison Between E(t) and F(t) Curves
`. . . . . . . . . . . . . . . . . . . . 0
`Statistical Considerations
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
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`v
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`p. E6
`
`

`

`Flow Characteristics in Selected Heat Exchangers . . . . . . . . . . . . . . . . . . . . 40
`Residence Time Distribution in Processing of Heterogeneous Foods ......... 41
`Scraped-Surface Heat Exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . 42
`Holding Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
`Effect of Residence Time Distribution on Sterilization Efficiency . . . . . . . . . . . 44
`References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
`Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
`
`Chapter 4 - Microbiology of Aseptic Processing and Packaging
`Introduction
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 7
`Growth of Microorganisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
`Properties of Microorganisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
`Properties of the Food
`Properties of the Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
`. . . . . . . . . . . . . . . . . . . . . . . . . . 50
`Destruction of Microorganisms in Food
`Destruction of Microorganisms by Heat . . . . . . . . . . . . . . . . . . . . . . 51
`Heat Resistance
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
`Thermal Processing of Foods with Particulates
`. . . . . . . . . . . . . . . . . 56
`Biological Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
`Inoculated Particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
`Simulated Particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
`Chemical Indices
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
`Removal of Microorganisms by Filtration
`. . . . . . . . . . . . . . . . . . . . 59
`Destruction of Microorganisms by Ultrasonic Waves . . . . . . . . . . . . . . 59
`Destruction of Microorganisms on Surfaces . . . . . . . . . . . . . . . . . . . . . . . . 60
`Hydrogen Peroxide (H20 2
`• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 60
`Irradiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
`Other Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
`Evaluating Package and Equipment Sterility . . . . . . . . . . . . . . . . . . . . . . . . 65
`Sterilization of Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
`Injured Microbial Cells and Spores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
`Thermal Injury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
`Radiation Injury
`H2~ Injury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
`Enzymes Produced by Microorganisms . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
`Microbial Spoilage of Aseptically Processed Foods
`. . . . . . . . . . . . . . . . . . . 70
`Microbiological Analyses for Assessing Finished Product Sterility
`. . . . . . . . . . 71
`Food-Borne Illness from Aseptically Processed Foods . . . . . . . . . . . . . . . . . . 73
`References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4
`
`Chapter 5 - Chemistry of Aseptically Processed Foods
`Introduction
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
`Activation Energy
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
`Determining Activation Energies . . . . . . . . . . . . . . . . . . . . . . . . . . 89
`Interpreting Activation Energies
`. . . . . . . . . . . . . . . . . . . . . . . . . . 91
`Chemical Changes in Aseptically Processed Foods . . . . . . . . . . . . . . . . . . . . 93
`Enzyme Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
`Protein Structure
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
`Enzyme Regeneration
`Age Gelation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
`
`vi
`
`p. E7
`
`

`

`\
`
`Browning Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
`Maillard Browning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
`Ascorbic Acid Browning
`. . . . . . . . . . . . . . . . . . . . . . . . . 101
`Lipid Browning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
`Problems Associated with Oxygen
`. . . . . . . . . . . . . . . . . . . . . . . . 102
`Sources of Oxygen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
`Methods of Measurement . . . . . . . . . . . . . . . . . . . . . . . . . 103
`Oxygen Diffusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
`Oxidative Browning
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
`Reducing Oxidative Browning
`. . . . . . . . . . . . . . . . . . . . . . 105
`Nutritional and Flavor Changes . . . . . . . . . . . . . . . . . . . . . . . . . . 105
`Changes in Natural Pigments
`. . . . . . . . . . . . . . . . . . . . . . . . . . . 106
`Techniques to Measure Chemical Changes
`. . . . . . . . . . . . . . . . . . . 107
`Shelf Life
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
`References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
`
`Chapter 6 - Aseptic Packaging Technology
`Introduction
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
`Packaging Functions and Objectives
`. . . . . . . . . . . . . . . . . . . . . . . . . . . 115
`Packaging Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
`Produ<;t Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
`Environmental, Transportation and Distribution of Hazards Information . 119
`Market Information
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
`Packaging Information
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
`Total Systems Approach
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
`Packaging Materials for Aseptically Processed Foods . . . . . . . . . . . . . . . . . 121
`Properties of Polymeric Packaging Materials . . . . . . . . . . . . . . . . . . 121
`Gas and Water Vapor Barrier Properties . . . . . . . . . . . . . . . . 121
`Mechanical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
`Thermal Stability and Sealing Properties . . . . . . . . . . . . . . . . 125
`Chemical Properties
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
`Light/UV Protective Properties
`. . . . . . . . . . . . . . . . . . . . . 126
`Composite Multilayer Structures
`. . . . . . . . . . . . . . . . . . . . . . . . . 126
`Selection of Appropriate Packaging Materials
`. . . . . . . . . . . . . . . . . 127
`Packages for Aseptically Processed Foods . . . . . . . . . . . . . . . . . . . . . . . . 129
`Package Formation Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
`Package Types and Characteristics . . . . . . . . . . . . . . . . . . . . . . . . 132
`Sterilization in Aseptic Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
`Package Sterilization Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
`. . . . . . . . . . . . . . . . . . . . . . . • . . . 13 8
`Mechanical Processes
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8
`Thermal Processes
`Irradiation Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
`Chemical Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
`Combinations
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
`. . . . . . . . . . . . . . . • . . . . . . . . . . 139
`Microbial Destruction Kinetics
`Aseptic Packaging Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
`Fill and Seal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . 140
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
`Erect, Fill and Seal
`Form, Fill and Seal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
`Thermoform, Fill and Seal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
`Blow Mold, Fill and Seal
`
`vii
`
`p. E8
`
`

`

`. . . . . . . . . . . . . . . . . . . . . . 141
`Bulk Packaging and Storage Systems
`Package Integrity Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
`Selection of an Aseptic Packaging System . . . . . . . . . . . . . . . . . . . . . . . . 143
`Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
`References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
`
`Chapter 7 - Polymeric Packaging Materials: Characterization and Performance
`Introduction
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
`Polymer Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
`Chemical Composition and Microstructure . . . . . . . . . . . . . . . . . . . 151
`Random Copolymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
`Alternating Copolymers . . . . . . . . . . . . . . . . . . . . . . . . . . 151
`Block Copolymers
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
`Grant Copolymers
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
`Molecular Weight and Molecular Weight Distribution . . . . . . . . . . . . 152
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
`Thermal Properties
`Morphology/Crystallinity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
`Heat Sealant Polymers
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
`Adhesion and Laminations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
`Adhesive/Cohesive Bond Failure . . . . . . . . . . . . . . . . . . . . . . . . . 161
`High Barrier Polymers and Laminations . . . . . . . . . . . . . . . . . . . . . . . . . 165
`Ethylene/Vinyl Alcohol (EV AL)
`. . . . . . . . . . . . . . . . . . . . . . . . . 165
`Silica-Coated Packaging Material . . . . . . . . . . . . . . . . . . . . . . . . . 168
`Oxygen Barrier ............ , . . . . . . . . . . . . . . . . . . . . . . . 168
`Moisture Barrier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
`Retortability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
`Sorption and Permeation Processes Associated
`. . . . . . . . . . . . . . . . . . . . 172
`with Loss of Aroma Compounds
`Selection and Location of Barrier Layer
`. . . . . . . . . . . . . . . . . . . . 174
`Concentration Dependence of the Transport Process
`. . . . . . . . . . . . . 176
`Temperature Dependency of the Transport Process . . . . . . . . . . . . . . 177
`Effect of Thermomechanical History . . . . . . . . . . . . . . . . . . . . . . . 177
`Effect of Relative Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
`Sorption Considerations
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
`In Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
`References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
`Figure Legends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
`
`Chapter 8 - Establishing the Aseptic Processing and Packaging Operation
`Introduction
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
`Product Sterilization Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
`. . . . . . . . . . . . . . . . . 224
`Influence of Product on Equipment Selection
`Determining and Controlling Product Flow Rate
`. . . . . . . . . . . . . . . 225
`Monitors and Controls
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
`Processing System Sterilization
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
`Maintenance of Sterility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227
`Establishing the Schedule Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
`. . . . . . . . . . . . . . . . . . . . . . . . . 228
`Identification of Critical Factors
`Calculating the Thermal Process
`. . . . . . . . . . . . . . . . . . . . . . . . . 229
`Process Confirmation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
`Aseptic Packaging Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
`
`viii
`
`p. E9
`
`

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`System Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
`Critical Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
`Biological Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
`Aseptic Package Integrity Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 236
`• 237
`Pre-Production Inspection ......... 0
`Base Material Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
`Hold for Investigation (HFI) Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 237
`Action for Specification Deviations
`. . . . . . . . . . . . . . . . . . . . . . . 238
`Determination of HFI Quantity . . . . . . . . . . . . . . . . . . . . . . . . . . 238
`Determination of Disposition of HFI Packages . . . . . . . . . . . . . . . . . 238
`Packaging Machinery
`. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
`Sampling Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
`Production Line Inspections - Visual . . . . . . . . . . . . . . . . . . . . . . . 238
`. . . . . . . . . . . . 239
`Procedures for Visual Inspection of Aseptic Packages
`Teardown Procedures for Paperboard Packages . . . . . . . . . . . . . . . . 239
`Teardown Procedures for Flexible Pouches . . . . . . . . . . . . . . . . . . . 240
`Peel Test Procedures for Form, Fill, and Seal Containers . . . . . . . . . . 240
`Test Methods for Package Integrity . 0 • • • • • • • • • • • • • • • • • • • • • • 0 • • • 241
`o 243
`References . o
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`Chapter 9 - Federal Regulation of Processing and Packaging
`• 245
`FDA Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0
`• 246
`Processing Authority
`. 0
`Better Process Control Schools . . . . . . . . . . . . . . . . . 0
`• 246
`Process Establishment and Process Filing . . . . . . . . . . . . . . . . . . . . 246
`Grade A Pasteurized Milk Ordinance Requirements . . . . . . . . . . . . . 0
`• 248
`PMO/GMP Variances . o • • • • • • • • • o • • o • • • • • • • • • • o
`• 248
`Conservative Nature of FDA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
`0 250
`Package Sterilants
`. . . . . . . . . . . 0
`• 250
`USDA Requirements 0 • • • • • 0 • • • • 0
`Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
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`Chapter 10 - Glossary of Terms .•.....................•........ 0
`
`• 252
`
`ix
`
`p. E10
`
`

`

`CHAPTER 1
`
`INTRODUCTION
`
`Philip E. Nelson
`
`The food industry is continually changing. One needs
`only to look back a few years to see the dynamic changes
`that have been rapidly occurring. The industry is in the
`beginning of another change that involves food packaging.
`The search is to find a container that is inexpensive, light(cid:173)
`weight, environmentally sound, and easy to transport.
`Above all, it must meet the consumers' needs. For these
`reasons, aseptic processing and packaging has moved
`aggressively into the U.S. food distribution system as a
`commercially feasible concept.
`In order to avoid any confusion over defmition, aseptic
`processing and packaging can be described as follows:
`
`Commercial Sterilization
`of Foods (Closed System)
`Cooled to
`Ambient Temperature
`
`Sterilization
`of
`Container
`
`Packaged in
`Sterile Environment
`at Ambient Temperatures
`
`Extended Shelf Life
`Without the Need of
`Refrigeration
`
`Surprisingly, aseptic processing is not a new technology.
`In fact, it has been used commercially in Europe and Japan
`for many years.
`In the United States, its developmental
`stages can be shown in the following time chart:
`
`1980
`
`1970
`
`1960
`
`1950
`
`1940
`
`FDA approval of H,02
`for sterilizing packages
`
`Aseptic Rail Tankers
`Aseptic Bag-in-Box
`
`Aseptic Flexible Packaging
`Aseptic Bulk Storage
`
`Aseptic Drums
`
`Martin/ Aseptic Canning
`
`While all of the above dates are significant, February
`1981 will be remembered as possibly the most important
`date for aseptic processing in the U.S. On this date, FDA
`approved the restricted use of hydrogen peroxide as a
`package sterilant. This approval provided the opportunity
`for the use of laminates for consumer-size packages. More
`than 500 aseptic systems are in place in the U.S. today.
`
`ASEPTIC PROCESS
`
`The commercial aseptic sterilization process takes place
`in a continuous, closed system. This system allows the use
`of highly efficient heat exchangers and the opportnnity for
`high temperature short time (HTST) and ultra high
`temperature (UHT) processes. Because of the shortened
`time/temperatures, aseptic processing should produce
`products with high nutritioual retainment and excellent
`sensory qualities. Tendencies to over process and to
`include excessive safety factors may negate these benefits.
`Cold sterilization of clear solutions can be accomplished by
`passing the liquid through a membrane filter with pore size
`small enongh to remove microorganisms.
`There are several established methoda available to
`thermally sterilize and cool a food product. Examples
`include:
`
`Indirect Heating
`Tubular
`Plate
`Scraped-Surface
`Electrical
`
`Direct Heating
`Steam Injection
`Steam Infusion
`
`The question of which heat exchangers to use is product
`specific, and all have advantages and disadvantages, which
`will be discussed in a later chapter.
`Important to the closed system of aseptic processing is
`the inclusion of deaeration. Since occluded and entrapped
`air will be present in most food products, methods to
`remove air must be placed in line, preferably before
`sterilization. Air removal results in improved product
`quality and an extended shelf life.
`
`p. E11
`
`

`

`A limiting factor for aseptic technology is processing
`products containing particulates at high temperatures.
`These particulates have often lost their shape and form
`during the beating and cooling steps. Developments in
`improved pumping, heating, and other equipment designs
`offer a bright future for overcoming these obstacles.
`
`MICROBIOLOGICAL EVALUATION
`
`Microbiological evaluation of a continuous processed
`product is, at best, difficult. While statistical aseptic
`sampling is important, reliance upon process controls is
`imperative. Fortunately, with the advance of aseptic
`processing automation. The need is to assure that the
`process bas met the established requirements and that the
`In
`human element is eliminated as much as possible.
`general, the process for sterilization and the equipment to
`prevent recontamination of the product are now readily
`available.
`
`THE PACKAGE
`
`Aseptic containers come in all sizes and shapes, from the
`small consumer packages to large 100,000+ gallons bulk
`storage tanks. The bag-in-box technology has grown
`significantly in the past few years. Its thrust has been in
`
`uuits ranging from 2 gallon to large 300 gallon units.
`Their use and performance by the industry bas been quite
`impressive. The use initially was aimed at remanufacture;
`however, new inroads into the institutional market are
`underway.
`In the case of the consumer package, the shelf life of the
`product bas been a major concern. Oxygen permeation bas
`caused limited shelf life of food products in contrast to the
`metal can or glass jars. However, new packaging materials
`with greater barrier properties are entering into the
`marketplace and are dramatically reducing this problem.
`Flavor "scalping" and uneven extrusion of the laminated
`materials are areas that need continued improvement and
`are receiving research and development priorities.
`There are numerous packaging systems available today
`which have already made a siguificant impact on the jnice
`It is believed that the semi-rigid, form-fill-seal
`market.
`packaging container will show the next major growth.
`All in all, aseptic processing has found a place in the
`industry, and its future for having an even greater impact
`is believed to be just around the corner. In the following
`chapters, the authors have attempted to focus on the
`significant areas that influence the success or failure of the
`process. As with any new technology, refmements and
`continued new applications impact its use. With the
`interest and involvement of major research units, aseptic
`its mark on the
`processing will continue to make
`distribution of our perishable food supply.
`
`2
`
`p. E12
`
`

`

`CHAPTER2
`THE SYSTEM AND ITS ELEMENTS
`Daryl B. Lund and Rakesh K. Singh
`
`INTRODUCTION
`
`addressed in a systematic manner, an aseptic
`processing system will emerge which results
`in acceptable product quality at an
`acceptable product cost.
`The system for aseptically processed
`foods is extremely complex mechanically
`and requires meticulous attention to detail if
`it is to operate successfully. The program
`for establishing and monitoring the system
`to ensure optimum performance will be
`covered in subsequent chapters.
`In this
`chapter, the principles of thermobacteriology
`for design of the heat transfer system will be
`presented, followed by a description of the
`actual elements which can be used
`to
`accomplish the objective(s) of the process.
`
`Figure 1. Diagram of an aseptic processing system.
`
`The aseptic processing system can be
`conveniently divided into several elements:
`(1) the product; (2) flow control; (3) product
`heating; (4) hold tube; (5) product cooling;
`and (6) packaging (Figure 1). Properties of
`the product dictate the possible options in
`designing an aseptic processing system.
`Product considerations include: (1) liquid or
`(2)
`size of
`liquid plus particulates;
`particulates;
`(3) product viscosity;
`(4)
`thermal sensitivity of product color and
`flavor; (5) volatility of product flavor; and
`(6) fouling characteristics of the product. If
`these characteristics are identified and
`,.- ...
`
`\
`I
`r -IDeaeralorr- ;
`-,
`~" II
`..-1...
`I
`\
`I
`' \ '~~'
`Product•
`lPumpJ-- -r
`--
`, ...... r
`,.._~Pum~r1
`Preheat
`1
`I
`1
`,,...,....
`..,_.,.
`1
`I
`I
`I
`L - - - - - - - - -_1
`-
`
`I L------------ -~- ---
`
`Finished r----1
`Product
`
`Asepllc
`Product
`Filler
`
`i
`
`Sampling ~
`Valve
`
`3
`
`~·-·..,
`, Heating •
`-f Heat
`t·-t:;:*-.- "l Hold
`I u
`, Exchanger •
`1 Divert
`• 1 be
`L·-·-·-' I
`1 Valve
`t
`I
`-----...1
`
`.
`
`(!) Back Pressure
`Valve or Pump
`
`Cooling
`Heal
`Exchanger
`
`Back Pressure
`Valve or Pump
`
`.... -,
`-lPump,_,
`'-~ I
`Sterno
`Addlllves
`
`p. E13
`
`

`

`BASIC PRINCIPLES
`
`Thermobacteriology
`
`The use of high temperatures to
`inactivate microorganisms or their spores to
`prolong the shelf life of foods is a very old
`process. Since the 1920's thermal processes
`have been designed based on parameters
`characterizing the thermal destruction of
`microorganisms
`and
`data on
`the
`time/temperature history of the product.
`Traditional! y the process has been applied to
`products in containers, and equipment has
`been developed and used extensively since
`the 1950s for the continuous "in-container"
`commercial sterilization.
`In the 1940s aseptic processing was
`It differed markedly from in(cid:173)
`developed.
`container processing.
`In conventional
`processing
`the nonsterile product
`is
`hermetically sealed in nonsterile containers