Thermal Processing of Packaged Foods Book

Preface First Edition     xiv
Preface Second Edition     xvi
Introduction     1
Thermal Processing Principles     1
Thermal Processing     1
The Process     1
Canning Operations     2
General     2
Methods of Processing     3
Packaging Materials     4
Introduction     4
Metal Containers     4
Glass Containers     6
Rigid Plastic Containers     7
Retortable Pouches     8
Some Historical Details     9
References     11
Heat Transfer     14
Introduction     14
General Aspects     14
Mechanisms of Heat Transfer     14
Heat Transfer by Conduction     16
Introduction     16
Formulation of Problems Involving Conduction Heat Transfer     17
Initial and Boundary Conditions     21
Mean or Volume Average Temperatures     22
Summary of Basic Requirements     23
Some Analytical Methods for Solving the Equations     24
Some Numerical Techniques of Solution     27
Some Analytical Solutions of the HeatTransfer Equation     35
Heat Transfer in Packaged Foods by Microwave Heating     43
Dielectric Heating     45
Heat Transfer by Convection     45
Introduction     45
Basic Concepts in Convection Heat Transfer     48
Models for Convection Heat Transfer     50
Some Experimental Work and Correlations     54
Conclusions     65
Radiation Heating     65
Some Computer Programs     69
Conduction Heat Transfer Analysis Programs     69
References     70
Kinetics of Thermal Processing     87
Introduction     87
General Effects of Thermal Processing     87
The Nature of Microbial Behaviour     87
Other Factors Affecting Heat Resistance     88
Measuring Heat Resistance     89
The Statistical Nature of Microbial Death     94
Practical Aspects     96
Methods of Representing Kinetic Changes     96
Basic Kinetic Equations     96
Decimal Reduction Time     99
More Complex Inactivation Models     100
Temperature Dependence of Death Rate     103
Kinetics of Food Quality Factor Retention      111
Introduction     111
Kinetic Representation     111
Kinetic Factors     112
Experimental Procedures     112
Specific Components     113
Summary     114
References     115
Sterilization, Pasteurization and Cooking Criteria     123
Sterilization Value     123
Definitions     123
Lethal Rates     123
Reference Temperatures     124
A processing Point of View to Derive F value     127
Integrated F-values, F[subscript S]     128
F-values for Cans of Differing Sizes     129
Arrhenius Approach     130
Cooking Values     131
Historical Perspective     131
Origin and Rationale of Cooking Value     133
Quality Retention     134
Pasteurization Value     134
Minimally Processed Foods     135
Acidified Products     135
Pasteurized/Chilled Products     136
Electrical Methods of Heating     136
Other Processes     137
Process Achievement Standards     137
Sterilization     137
Cooking      138
References     138
Heat Penetration in Packaged Foods     142
Introduction     142
Heat Transfer and Product Characteristics     142
Experimental Determination     145
Temperature Monitoring     145
Thermocouple Errors     147
Thermocouple Calibration     148
Thermocouple Location: Slowest Heating Point     148
Model Systems     150
Graphical Analysis of Heat Penetration Data     151
The Linear Plot     151
The Semi-logarithmic Plot     152
Analysis of Heat Penetration Graphs     152
Theoretical Analysis of Heat Penetration Curves     159
Conduction-Heating Packs     159
Convection-Heating Packs     160
Computer Modeling     161
Factors Affecting Heat Penetration     161
Effect of Container Shape and Dimensions     161
Effect of Initial Temperature     163
Effect of Position Inside the Container     164
Effect of Headspace     164
Effect of Variation of Physical Properties with Temperature     164
Effect of External Heat-transfer Coefficients     164
Effect of Container Material and Thickness      166
Effect of Can Rotation     166
Statistical Aspects of Heat Penetration Data     167
Extrapolation of Heat Penetration Data     167
Simulation of Thermal Processing of Non-symmetric and Irregular-Shaped Foods Vacuum Packed in Retort Pouches: A Numerical Example     167
Reverse Engineering by 3-D Digitizing     168
Simulation of Heat Conduction Processes     169
Finite Element Analysis     170
Experimental Validation     170
References     171
Process Evaluation Techniques     176
Determination of F-Values: Process Safety     176
The General Method     176
Graphical Methods     177
Numerical Methods     178
An Extension of General Method: Revisited General Method (RGM)     181
Analytical Methods     189
Constant Temperature with Time     190
Linear Temperature Gradient     190
Exponential Temperature Rise     190
The Exponential Integral     191
Some Formula Methods     192
Introduction     192
Ball's Methods     192
Gillespi's Method     201
Hayakawa's Method     206
Other Methods      209
Mass-average Sterilizing Values     213
Some Factors Affecting F-Values     214
Introduction     214
Statistical Variability of F-Values     215
Microbiological Methods     218
Introduction     218
Inoculated Pack Method     218
Encapsulated Spore Method     219
Biological and Chemical Indicators     219
Conclusion     222
A Guide to Sterilization Values     223
Computerised Process Calculations     224
References     227
Quality Optimization     239
Introduction     239
Cooking versus Microbial Inactivation     240
Process Evaluation     242
Some Models for Predicting Nutrient and Cooking Effects     242
Some Typical C-values     243
Optimization of Thermal Processing Conditions     244
Graphical Approach     244
Optimization Models     246
Quality Assessment Through Mass Balance     258
Demonstration Examples     259
Corollary     262
Conclusions     262
References     262
Engineering Aspects of Thermal Processing      270
Thermal Processing Equipment     270
Introduction     270
Batch Retorts     273
Continuous Cookers     277
Heat Transfer Media     280
Total and Transient Energy Consumption in Batch Retort Processing     292
Mathematical Model for Food Material     293
Mass and Energy Balance During Venting     293
Mass and Energy Consumption between Venting and Holding Time (To Reach Process Temperature)     295
Mass and Energy Balance During Holding Time     296
Numerical Results     297
Pressures in Containers     297
Development of Internal Pressures     297
Internal Pressure Calculation     298
Processing Requirements     299
Semi-rigid Containers     299
Mechanical Agitation and Rotation of Cans     300
End-over-end Agitation     300
Axial Rotation and Spin Cooking     300
Steritort and Orbitort Processes     304
Shaka Retort Process     304
Commercial Pasteurizers     304
Computer Simulation of Fluid Dynamics Heat Transfer     305
Batch Processing and Retort Scheduling     305
Batch Processing Problem Structure in Canned Foods     306
Batch Processing in Canned Food Plants     307
The Hierarchical Approach     308
Retort Scheduling     308
Simultaneous Sterilization of Different Product Lots in the Same Retort     312
Simultaneous Sterilization Characterization     313
Mathematical Formulation for Simultaneous Sterilization     313
Computational Procedure     315
Expected Advantages on the Implementation of Simultaneous Sterilization     315
References     315
Retort Control     325
Process Instrumentation     325
Introduction     325
Temperature Measurement     326
Pressure Measurement     328
Water Level     328
Rotation Monitors     329
Lethality Measurement     329
Process Control     330
Introduction     330
Control Valves and Actuators     331
Interfaces     331
Control Systems     332
Computer Control     332
Process Dynamics     333
Retort Control     334
Control of Batch Retorts     334
Efficient and General On-line Correction of Process Deviations in Batch Retort     335
Control of Hydrostatic Sterilizers     341
Control of Continuous Reel and Spiral Pressure Cookers     342
Derived-value Control     342
Guidelines for Computer Control     343
Industrial Automation of Batch Retorts     343
References     349
Safety Aspects of Thermal Processing     354
Introduction     354
Information Sources     354
Legislation and Codes of Practice     354
GMP Guidelines and Recommendations     355
Technical Training     355
Some Techniques for the Implementation of GMP     356
HACCP Techniques     356
Process Audits     357
Aspects of GMP     357
Identification of Critical Factors     357
Process Deviations     359
Thermal Process Validation     359
Process Establishment     359
Lethality Assurance     360
Records     360
References     361
Kinetic Factors for Microbial Inactivation     363
Kinetic Factors for Quality Attributes     375
Heat Penetration Protocols     392
FDA Food Process Filing      393
Index     394