Essentials of thermal processing

Cover
Title Page
Copyright Page
Contents
Preface
Glossary of Terms
Chapter 1 History of Thermal Processing
	1.1 A brief history of the science and technology of thermal processing
	1.2 Food microbiology as a science
	1.3 Packaging for heat preserved foods
		1.3.1 Convenience – the can opener is invented
		1.3.2 Other forms of packing for ‘canned foods’
	1.4 Developments in cannery equipment
		1.4.1 Seaming
		1.4.2 Processing
	1.5 Food safety
	References
Chapter 2 Microbiology of Heat Preserved Foods
	2.1 Food microbiology
		2.1.1 Fungi
			2.1.1.1 Moulds
			2.1.1.2 Yeasts
		2.1.2 Bacteria
			2.1.2.1 Growth and reproduction of bacteria
	2.2 Factors that affect the growth of micro-organisms
		2.2.1 pH
		2.2.2 Moisture
		2.2.3 Nutrients
		2.2.4 Oxidation–reduction potential
		2.2.5 Antimicrobial resistance
		2.2.6 Biological structures
		2.2.7 Relative humidity
		2.2.8 Oxygen content/concentration of gases in the environment
		2.2.9 Temperature
			2.2.9.1 D-value
			2.2.9.2 z-value
	2.3 Description of some micro-organisms of importance to thermal processing
		2.3.1 Moulds
		2.3.2 Yeasts
		2.3.3 Bacteria
			2.3.3.1 Thermophiles
			2.3.3.2 Mesophiles – spore-forming bacteria
			2.3.3.3 Mesophiles – non-spore-forming pathogenic and spoilage bacteria
			2.3.3.4 Psychrophiles
	2.4 Risk of leaker spoilage from damaged or compromised packaging
	2.5 A guideline for identifying spoilage in canned foods
	References
Chapter 3 Hurdles to Microbial Growth
	3.1 Control of the micro-organism loading
	3.2 Use of restrictive pH levels
	3.3 Anaerobic environment or modified atmosphere environment
	3.4 Low temperatures
	3.5 Dehydration or low water activity
	3.6 Chemical preservation
		3.6.1 Organic acids
			3.6.1.1 CIMCSEE code
		3.6.2 Sulphites and nitrites
		3.6.3 Antibiotics
		3.6.4 Antioxidants
	3.7 Irradiation
	3.8 Combination treatments
	References
Chapter 4 Low-acid Canned Foods
	4.1 Production of a thermally processed food
	4.2 F03 sterilisation processes
	4.3 Commercial sterilisation
	4.4 Micro-organism death kinetics
	4.5 Log reductions
	References
Chapter 5 Acid Foods and Other Pasteurised Products
	5.1 Background
		5.1.1 Naturally acid foods
	5.2 Pasteurisation
		5.2.1 Considerations when designing a safe pasteurisation process
		5.2.2 Calculation of pasteurisation values
	5.3 Inhibitory factors to micro-organism growth
	5.4 Pasteurisation value (p-value) guidelines
		5.4.1 High acid: pH < 3.5
		5.4.2 Acid: pH 3.5–4.0
		5.4.3 Acid: pH 4.0–4.2
		5.4.4 Medium acid: pH 4.2–4.6
	5.5 Guidelines and general recommendations
		5.5.1 Guidelines to critical factors in thermal processing of acid foods
	5.6 Thermal processing of fruit
		5.6.1 Packaging selection
		5.6.2 Oxidation reactions inside an internally plain can of acid fruit
		5.6.3 Pigments that discolour in internally plain cans
	5.7 Thermal processing of products with low water activity
		5.7.1 Jam and high sugar preserves
		5.7.2 Canned cakes and sponge puddings
		5.7.3 Bacteria of concern
		5.7.4 Yeast and mould
		5.7.5 Process recommendations – cake
		5.7.6 Process recommendations – bread
	5.8 Thermal processing of cured meats
	References
Chapter 6 Acidified Foods
	6.1 Background
	6.2 Acidity measurement using pH
		6.2.1 The history of pH
		6.2.2 The chemistry of pH
		6.2.3 Measurement of pH
			6.2.3.1 Potentiometric method
			6.2.3.2 Colorimetric measurement
		6.2.4 Equilibrium pH
	6.3 Acidification of foods
	6.4 Processing acidified foods
	6.5 Design of pasteurisation processes
		6.5.1 Medium acid range: pH 4.2–4.6
		6.5.2 Acid range: pH 3.5–4.2
		6.5.3 High acid range: pH below 3.5
	6.6 Hot fill and hold processing
	6.7 Critical control points in the production of acidified foods
		6.7.1 Ingredients
		6.7.2 Heat processing
		6.7.3 Post process equilibrated pH
		6.7.4 Container integrity
		6.7.5 pH during product shelf life
	References
Chapter 7 Heat Preserved Chilled Foods
	7.1 Understanding microorganism behaviour
		7.1.1 Pathogenic microorganisms relevant to chilled foods
			7.1.1.1 Clostridium botulinum
			7.1.1.2 Bacillus cereus
		7.1.2 Microorganisms likely to be found in chilled foods
	7.2 Methods of manufacture
		7.2.1 Thermal process step applied prior to packaging
			7.2.1.1 Low care–high care factories
		7.2.2 Thermal process step applied after packaging
			7.2.2.1 Caution with latent heat for frozen protein
	References
Chapter 8 Processing Systems
	8.1 In-pack processing: retort systems
		8.1.1 Condensing steam retorts
		8.1.2 Crateless retorts
		8.1.3 Water immersion retorts
		8.1.4 Water spray and cascade
		8.1.5 Steam/air retorts
		8.1.6 Shaka retorts
		8.1.7 Reel and spiral retorts
		8.1.8 Hydrostatic retorts
	8.2 In-line processing: heat exchangers
		8.2.1 Flow behaviour
		8.2.2 Choice of heat exchanger
		8.2.3 Maximising product recovery
	8.3 New thermal technologies
	References
Chapter 9 Cook Values and Optimisation of Thermal Processes
	9.1 Mathematical analysis of cooking
		9.1.1 Cooking equations and kinetic data
		9.1.2 Competition between sterilisation and cooking
		9.1.3 Optimisation of temperature/time in processing
	9.2 Setting process targets
		9.2.1 How to select processing conditions without excess quality damage
	References
Chapter 10 Process Validation: Temperature and Heat Distribution
	10.1 Temperature distribution
		10.1.1 Temperature measurement systems
	10.2 Heat distribution
		10.2.1 Modes of heat transfer
			10.2.1.1 Radiation
			10.2.1.2 Conduction
			10.2.1.3 Convection
			10.2.1.4 Broken heating or mixed heating
	10.3 Heat distribution testing
		10.3.1 Conducting a HD test
	References
Chapter 11 Process Validation: Heat Penetration and Process Calculations
	11.1 Setting the target process value
	11.2 Selecting the conditions for the HP study
		11.2.1 Product
		11.2.2 Container or package
		11.2.3 Retort or processing system
	11.3 Locating the product cold point
	11.4 Process establishment methods
		11.4.1 Log reduction methods for HP testing
			11.4.1.1 Microbiological spore methods
			11.4.1.2 Biochemical systems
	11.5 Process calculation methods
		11.5.1 General method
		11.5.2 Ball method
		11.5.3 Numerical methods
		11.5.4 Continuous flow with particulates
	References
Chapter 12 Cooling Water Treatment
	12.1 Chlorine
		12.1.1 Chlorine demand and residual chlorine
		12.1.2 Using chlorine
	12.2 Chlorine dioxide
	12.3 Bromine
	12.4 Ozone
	12.5 Ultraviolet light
	12.6 Membrane filtration
	References
Chapter 13 Handling Processing Deviations
	13.1 What constitutes a process deviation
	13.2 What can go wrong
	13.3 Actions required
		13.3.1 TPA actions
		13.3.2 Process deviation analysis for broken heating products
		13.3.3 Reprocessing
Chapter 14 Packaging Options for Heat-Preserved Foods
	14.1 Metal containers
		14.1.1 Tin plate
		14.1.2 Tin free steel (TFS or ECCS)
		14.1.3 Aluminium
		14.1.4 Protective coatings (lacquers)
			14.1.4.1 Vinyl lacquers
			14.1.4.2 Organosol lacquers
			14.1.4.3 Epoxy-phenolic lacquer
			14.1.4.4 Polyester lacquer
			14.1.4.5 Acrylic lacquers
			14.1.4.6 Side stripe lacquers to cover the weld
		14.1.5 Internally plain (unlacquered) cans
		14.1.6 External covering
	14.2 Can construction and handling
		14.2.1 Product specification
		14.2.2 Storage and handling of empty unused cans and ends
		14.2.3 Cleaning of empty unused cans
		14.2.4 Double seam formation and inspection procedures
		14.2.5 Washing of filled cans
		14.2.6 Processing of cans
		14.2.7 Cooling of cans
			14.2.7.1 Corrosion prevention
		14.2.8 Secondary packaging
	14.3 Glass
		14.3.1 Glass manufacture
		14.3.2 Closures for sealing glass food containers
		14.3.3 Sealing mechanisms
		14.3.4 Inspection procedures
		14.3.5 Packing and processing
			14.3.5.1 Inspection and preparation of containers
			14.3.5.2 Filling
			14.3.5.3 Capping
			14.3.5.4 Atmospheric processing
			14.3.5.5 Pressure processing
			14.3.5.6 Cooling
	14.4 Plastics, flexibles, and laminates
		14.4.1 Advantages of retortable plastics
		14.4.2 Disadvantages of retortable plastics
		14.4.3 Polymers used for retortable packaging
			14.4.3.1 Polypropylene (PP)
			14.4.3.2 Polyethylene terephthalate (PET)
			14.4.3.3 Ethyl-vinylalcohol (EVOH)
			14.4.3.4 Polyvinylidene chloride (PVDC)
			14.4.3.5 Polyamide (PA)
			14.4.3.6 Aluminium
			14.4.3.7 Glass-coated barrier films
		14.4.4 Types of packages used for thermally processed foods
			14.4.4.1 Retort pouches
			14.4.4.2 Plastic cans and pots
			14.4.4.3 Retortable composite carton
			14.4.4.4 Processing considerations – control of headspace
	References
Chapter 15 Incubation Testing
	15.1 Purpose of incubation tests
	15.2 Causes of spoilage
		15.2.1 Leaker spoilage
		15.2.2 Under processing
		15.2.3 Thermophilic spoilage
	15.3 Descriptive terms for canned food spoilage
	15.4 Methods for incubation testing
		15.4.1 Sample size
		15.4.2 Temperatures and times for incubation
			15.4.2.1 Thermophilic organisms
			15.4.2.2 Mesophilic organisms
		15.4.3 Post-incubation inspection of containers
	15.5 Biotesting
	References
Chapter 16 Critical Factors in Thermal Processing
	16.1 Background
	16.2 Key aspects of hygiene control systems for food processing (from codex alimentarius)
	16.3 Identifying critical control points in thermal processing
		16.3.1 Microbial load or bio-burden
		16.3.2 pH of the product
		16.3.3 Water activity (aw)
		16.3.4 Consistency
		16.3.5 Presence, concentration, and types of preservatives
		16.3.6 Rehydration
		16.3.7 Blanching
		16.3.8 Size and style of in-going ingredients
		16.3.9 Container, packing, and filling considerations
			16.3.9.1 Headspace
			16.3.9.2 Container vacuum and exhausting of containers
			16.3.9.3 Container size and geometry
			16.3.9.4 Initial temperature of product
		16.3.10 Process-related critical factors
			16.3.10.1 Processing method
			16.3.10.2 Processing medium
			16.3.10.3 Type and characteristics of heat-processing system
			16.3.10.4 Processing temperature
			16.3.10.5 Processing time
			16.3.10.6 Processing at high altitude
	References
Chapter 17 Environmental Aspects of Thermal Processing
	17.1 Lifecycle assessment (LCA)
		17.1.1 Impact categories
			17.1.1.1 Global warming potential (GWP)
			17.1.1.2 Pesticide use/ecotoxicity
			17.1.1.3 Abiotic resource use
			17.1.1.4 Acidification potential
			17.1.1.5 Eutrophication potential
			17.1.1.6 Land use
			17.1.1.7 Water use
	17.2 Greenhouse gas emissions
		17.2.1 Case study: Bottled apple juice
			17.2.1.1 Raw materials (0.407 kg CO2e/PU)
			17.2.1.2 Manufacture (0.061 kg CO2e/PU)
			17.2.1.3 Transportation (0.057 kg CO2e/PU)
			17.2.1.4 Waste (0 kg CO2e/PU)
			17.2.1.5 Overall carbon footprint (0.525 kg CO2e/PU)
			17.2.1.6 GHG emissions for other food products
	References
Index
EULA