Cover
Title Page
List of Contributors
1 Packaging for nonthermal processing of food: Introduction
1. NONTHERMAL PROCESSING
2. FACTORS TO BE CONSIDERED DURING NONTHERMAL PROCESSING
3. PACKAGING FOR NONTHERMAL PROCESSING
4. CONSUMER PREFERENCE OF PACKAGING DESIGN AND REGULATION OF NONTHERMAL PROCESSING
5. REFERENCES
2 Active packaging and nonthermal processing
1. INTRODUCTION
2. ACTIVE PACKAGING SYSTEMS
3. CONSIDERATIONS FOR COMBINING AP WITH NTP
4. CONCLUSIONS
5. REFERENCES
3 Antimicrobial packaging in combination with nonthermal processing
1. INTRODUCTION
2. COMBINATION OF PEFS WITH ANTIMICROBIAL COATED BOTTLE
3. COMBINATION OF HPP WITH ANTIMICROBIAL FILM AND COATING
4. COMBINATION OF PULSED LIGHT (PL) WITH ANTIMICROBIAL COATING
5. COMBINATION OF GAMMA IRRADIATION WITH ANTIMICROBIAL FILM
6. COMBINATION ULTRAVIOLET (UV) WITH ANTIMICROBIAL COATING
7. COMBINATION OF OZONATED WATER WASHING WITH ANTIMICROBIAL COATING
8. TERNARY COMBINATIONS
9. CONCLUSIONS
10. REFERENCES
4 Atmosphere packaging for nonthermal processing of food: High CO₂ package for fresh meat and produce
1. INTRODUCTION
2. HIGH CO₂ MAP PACKAGE
3. HIGH CO₂ PACKAGE FOR RAW MEAT PRODUCTS
4. HIGH CO₂ PACKAGE FOR FRESH PRODUCE PRODUCTS
5. CONCLUSIONS
6. REFERENCES
5 The use of biological agents in processing
1. INTRODUCTION
2. COMMON BIOLOGICAL AGENTS USED IN FOOD PROCESSING
3. REFERENCES
6 Packaging for high‐pressure processing, irradiation, and pulsed electric field
1. SUMMARY
2. INTRODUCTION TO PACKAGING FOR HPP
3. HOW HPP IMPACTS THE FOOD AND THE PACKAGING
4. INTRODUCTION TO FOOD IRRADIATION
5. HOW IRRADIATION IMPACTS THE FOOD AND THE PACKAGING
6. THE TYPES OF PACKAGING THAT ARE SUITABLE FOR HPP, IRRADIATION, AND PEF
7. FACTORS THAT MUST BE CONSIDERED WHEN APPLYING HPP TO PACKAGING
8. THE TYPES OF PACKAGING THAT ARE SUITABLE FOR IRRADIATION
9. THE TYPES OF PACKAGING THAT ARE SUITABLE FOR PEF
10. CONCLUSION
11. REFERENCES
7 Packaging for new and emerging food processing technology
1. INTRODUCTION
2. PEF TECHNOLOGY
3. PACKAGING REQUIREMENTS FOR FOODS PROCESSED BY PEF
4. OZONE (O₃) TECHNOLOGY
5. COLD OR NONTHERMAL PLASMA TECHNOLOGY
6. PULSED LIGHT (PL) TECHNOLOGY
7. REFERENCES
8 Packaging for foods treated by ionizing radiation: An update
1. INTRODUCTION
2. FDA APPROVAL PROCESSES FOR PACKAGING TREATED WITH IONIZING RADIATION
3. APPROVED PACKAGING MATERIALS FOR TREATMENT WITH IONIZING RADIATION
4. EFFECTS OF IONIZING RADIATION ON PACKAGING AND FORMATION OF RADIOLYSIS PRODUCTS (RPs)
5. UPDATED REVIEW OF RPs FROM POLYMER ADJUVANTS
6. MODELING EXPOSURE FOR PREPACKAGED FOODS TREATED WITH IONIZING RADIATION
7. CONCLUSION
8. ACKNOWLEDGMENT
9. REFERENCES
9 Packaging technology for microwave sterilization
1. INTRODUCTION
2. PACKAGING FOR MW STERILIZATION
3. CURRENT DEVELOPMENT IN HIGH‐BARRIER POLYMERIC PACKAGING
4. INTERACTION BETWEEN MW STERILIZATION AND POLYMERIC PACKAGING
5. INTERACTION BETWEEN PACKAGING AND STERILIZED FOOD
6. SUMMARY AND FUTURE DEVELOPMENT
7. ACKNOWLEDGMENT
8. REFERENCES
10 The influence of package design on consumer purchase intent
1. TRENDS DRIVING FOOD PACKAGING
2. CONSUMER DECISION MAKING AND PURCHASE INTENT
3. PRODUCT FAILURES
4. RESEARCH ON CONSUMER PACKAGING PREFERENCES
5. BUILDING AN EVIDENCE BASE FOR PACKAGING DESIGN
6. REFERENCES
11 Safety regulation of food packaging and food contact material in the European Union and the United States
1. INTRODUCTION
2. THE REGULATION OF FOOD CONTACT MATERIALS IN THE EUROPEAN UNION
3. THE REGULATION OF FOOD CONTACT MATERIALS IN THE UNITED STATES
4. CONCLUSION
5. REFERENCES
12 The forecast for intelligent packaging in the near future and the influence of nonthermal technologies on its performance
1. INTRODUCTION
2. INTELLIGENT PACKAGING
3. CHROMISM AND FOOD PACKAGING
4. INTELLIGENT PACKAGING, SENSORS, AND NONTHERMAL TECHNOLOGIES
5. QUICK RESPONSE AND BARCODES
6. RADIO FREQUENCY IDENTIFICATION DEVICES
7. NANOPARTICLES AND INTELLIGENT PACKAGING
8. CONCERNS ABOUT INTELLIGENT PACKAGING
9. REFERENCES
Index
End User License Agreement

List of Tables

Chapter 01
1. Table 1.1 List of process consideration, benefits, and shortcoming of alternative nonthermal processing methods (reprinted from Neetoo and Chen, 2014, pp. 145–147).
2. Table 1.2 Packaging materials and adjuvants approved for irradiation by the U.S. Food and Drug Administration (FDA).
Chapter 03
1. Table 3.1 Survival of L. monocytogenes on vacuum‐packaged RTE turkey after treatments.^*
Chapter 04
1. Table 4.1 Recommended high CO₂ package for raw meat products in retail (modified from Dansensor, 2016, Farber, 1991, Parry, 1993, and Scetar et al., 2010).
2. Table 4.2 CO₂ limits for horticultural crops and fresh‐cut products (modified from Watkins, 2000).
3. Table 4.3 Results of the triangle tests comparing taste of 0 or 30% CO₂ to 75% CO₂ for different fresh‐cut produce after storage at 7 °C.
Chapter 06
1. Table 6.1 Food types and radiation dosage approved by the U.S. FDA within the United States.
2. Table 6.2 Packaging materials and adjuvants approved for irradiation by the U.S. FDA.
Chapter 08
1. Table 8.1 AO and RP residual levels, concentration in food and dietary concentrations (DC) for monolayer and multilayers.
2. Table 8.2 Residual AO and RP levels to be used for migration modeling.
3. Table 8.3 Modeled migration and dietary concentration values for AOs and RPs.
Chapter 09
1. Table 9.1 Density of common glass, metal, and polymers for sterilized‐food packages.
2. Table 9.2 Effect of MATS and other thermally processing on the barrier properties of several EVOH‐ and PET‐based multilayer packaging films.
3. Table 9.3 Shelf life prediction of MATS‐processed model food in three polymer pouches * (MFA, MFB, and MFC) and a foil pouch (MF0) using ΔE =12 as the end point.
Chapter 10
1. Table 10.1 Summary of food packaging research studies.

List of Illustrations

Chapter 01
1. Figure 1.1 Increasing of HPP, irradiation, and pulsed electric field researches from 2001 to 2016 (https://www.ifis.org/fsta).
Chapter 03
1. Figure 3.1 Survival of total aerobic bacteria (a) and molds and yeasts (b) in pomegranate juice processed at bench‐scale PEF system. UT: untreated; UT + AB: untreated and packaged in antimicrobial bottle; PEF: PEF proccessed; PEF + AB: PEF procecssed and packaged in antimicrobial bottle.
2. Figure 3.2 Total phenolics (a) and antioxidant (b) compounds of pomegranate juices after treatments and stored at 4 °C for seven days.
3. Figure 3.3 Growth of L. monocytogenes on vacuum‐packed cooked chicken treated with HPP, active packaging (AP), and a combination of HPP and active packaging (HPP/AP) during storage at 4 °C (a) and 8 °C (b).
4. Figure 3.4 L. innocua populations in green bean samples after treatments. Nontreatment (control), coating application alone (coating) and in combination with HHP (coating + HHP). Applied HHP treatments (a) were: 200 MPa for five minutes (HP1), 300 MPa for five minutes (HP2), and 400 MPa for five minutes (HP3).
5. Figure 3.5 L. innocua populations in green bean samples after treatments. Nontreatment (control), coating application alone (coating) and in combination with PL (coating + PL). Applied PL treatments were: 3 x 10⁴ J/m² per side (PL1), 6 x 10⁴ J/m² per side (PL2), and 1.2 x10⁵ J/m² per side (PL3).
6. Figure 3.6 Effect of coating treatment in combination with gamma irradiation on populations of L. innocua on green beans samples during storage at 4 °C.
7. Figure 3.7 Effect of UV‐C treatment at different doses (2 kJ/m², 4 kJ/m², 8 kJ/m², and 10 kJ/m²) and UV‐C treatment (8 kJ/m²) in combination with coating treatment on L. monocytogenes population on broccoli florets. Coating treatment is applied before UV‐C treatment (coating + UVC) and after UV‐C treatment (UVC + coating).
8. Figure 3.8 Effect of coating treatment in combination with UV‐C on populations of L. innocua on green bean samples during storage at 4 °C.
9. Figure 3.9 Survival of natural psychrotrophs and L. innocua on shrimp after treatments. OW: ozone water washing; CC: chitosan coating; OW + CC: ozone water washing followed by chitosan coating.
10. Figure 3.10 Effect of combined treatment of ozonated water (7 ppm for 2.5 minutes) and coating treatment on the population of L. monocytogenes on broccoli florets.
11. Figure 3.11 Effect of coating treatment in combination with ozonated water washing on populations of L. innocua on green bean samples during storage at 4 °C.
12. Figure 3.12 Survival of natural psychotrophs on shrimp after treatments. NT: no treatment; CF: cryogenic freezing treatment; OW: ozone water treatment; CC: chitosan‐coating treatment; OW + CC + CF: ozone water treatment followed by coating treatment and cryogenic freezing.
13. Figure 3.13 Change in the populations of total aerobic bacteria of “Goha” strawberries during storage at 4 °C.
14. Figure 3.14 Microbial survival on ginseng roots after treatments and during storage at 4 °C. A: total bacteria; B: molds and yeasts. SW: sanitizer washing; UV: UV light treatment; CT: chitosan coating; SW/UV/CT: sanitizer washing followed by UV treatment and coating.
Chapter 04
1. Figure 4.1 Effects of high CO₂ packages on headspace gas composition, shelf life, and microbial growth on fresh‐cut pineapple during storage at 7 °C.
2. Figure 4.2 Effect of permeability (oxygen transmission rate [OTR] per oz of products in package) of microperforated films on CO₂ and O₂ contents in headspace in high CO₂ fresh‐cut produce packages.
3. Figure 4.3 Shelf life evaluations of texture and aroma attributes of fresh‐cut cantaloupe packed in high CO₂ (30%) atmosphere packages (score <5 means that the product is unacceptable; the fresh‐cut cantaloupe batch was processed on the different date by following the same processing method and using different raw materials).
4. Figure 4.4 Microbial colony formed on fresh‐cut cantaloupe in high CO₂ atmosphere packages.
5. Figure 4.5 Microflora on fresh‐cut cantaloupe packed in high CO₂ atmosphere packages during storage.
6. Figure 4.6 Relationship between microbial populations and overall product acceptance in fresh‐cut cantaloupe during storage at 2 °C. Test: Cantaloupe was processed under an ideal condition; control: Cantaloupe was processed under a simulated commercial condition. Both samples were packed under high CO₂ atmosphere. (a) sensory consumer test results; (b) total plate counts; (c) LAB counts.
7. Figure 4.7 Relationship between microbial populations and overall product acceptance in fresh‐cut cantaloupe during storage at 7 °C. Test: Cantaloupe was processed under an ideal condition; control: Cantaloupe was processed under a simulated commercial condition. Both samples were packed under high CO₂ atmosphere. (a) sensory consumer test results; (b) total plate counts; (c) LAB counts.
8. Figure 4.8 Effect of initial microflora on shelf life of fresh‐cut cantaloupe packed under high CO₂ atmosphere. (a) LAB counts; (b) sensory consumer test results.
Chapter 05
1. Figure 5.1 The chemical structure of nisin (C₁₄₃H₂₃₀N₄₂O₃₇S₇).
2. Figure 5.2 The repeating polymeric unit of polylysine.
3. Figure 5.3 Chemical structure of natamycin.
Chapter 06
1. Figure 6.1 A pilot size batch HPP unit.
2. Figure 6.2 The Radura that is printed on the labels of irradiated packaged foods.
3. Figure 6.3 A nuclear reactor containing cobalt‐60 stored under water.
4. Figure 6.4 The sample holder for products that are to be irradiated.
5. Figure 6.5 An illustration of polymerization by an addition reaction.
6. Figure 6.6 Illustrations of polymerization by condensation reactions.
7. Figure 6.7 An illustration of the induction sealing of a bottle.
Chapter 09
1. Figure 9.1 Second generation of 915‐MHz MATS system at Washington State University.
2. Figure 9.2 Typical structure of commercially available high barrier retort grade polymeric films containing EVOH (a) and PET‐silicon oxide coating (b) as functional barrier layers.
3. Figure 9.3 Organic barrier coating to provide better barrier properties after cross‐linking during thermal processing.
4. Figure 9.4 Changes in oxygen transmission rate (OTR) and the dielectric loss tangent (ɛ''/ɛ') of an EVOH‐based film (Nylon/EVOH/CPP) after MATS and during storage.
Chapter 10
1. Figure 10.1 A model of consumer responses to packaging form.
Chapter 11
1. Figure 11.1 FCM symbol.
Chapter 12
1. Figure 12.1 Capsules made with edible casings.
2. Figure 12.2 Photograph of a heat‐induced color‐changing polymeric material used to make smart cup lids.
3. Figure 12.3 Photographs of a pressure‐induced color‐changing plastic material inserted inside bottle caps: A – bottle not sealed, B – bottle sealed.
4. Figure 12.4 (a) Compression shear‐assembly of polymer opal. (b‐c) Optical images under natural lightning. (b) Undoped and (c) doped with carbon nanoparticles (Pursiainen et al., 2007).
5. Figure 12.5 Photograph of an intelligent package.
6. Figure 12.6 A barcode.
7. Figure 12.7 A QR code.
8. Figure 12.8 A RFID tag.
9. Figure 12.9 The optimum orientation of nanoplates within the matrix of a polymer. The red line is the torturous part of a gas diffusing through the film.
10. Figure 12.10 Photographs show plastic bottles washed up by the sea in South America.

1
Packaging for nonthermal processing of food: Introduction

Naerin Baek¹, Jung H. Han¹, and Melvin A. Pascall²

¹ Pulmuone Foods USA, Fullerton, California, USA

² Department of Food Science and Technology, Ohio State University, Columbus, Ohio, USA

Nonthermal processing technologies are food preservation methods designed to eliminate pathogenic and food spoilage microorganisms at low temperatures, when compared with commonly used thermal processes that use more heat (Min et al., 2005). Interests in nonthermal processing technologies have grown in food industry and academic laboratories due to the benefits associated with them. These include minimal impact on nutritional compositions, freshness and flavors, and the extension of shelf life, while diminishing the risk of pathogenic and food spoilage microorganisms. These technologies deliver convenience and efficiency of energy/water utilization when compared with conventional thermal treatments. Currently, some nonthermal processing treatments are commercially available, but others are still in the developmental stages for industrial applications.

Food products to be processed by nonthermal treatments are required to have specific characteristics when compared to similar foods that are thermally processed. Specific packaging materials and systems are required for nonthermally treated foods in order to achieve and maintain the safety and quality attributes of the products. Packaging materials selected for exposure to nonthermal processing must have good resilience and gas barrier properties in order to tolerate the physical and mechanical stresses of the process environment. Examples of nonthermal processing and preservation methods include technologies such as high pressure processing (HPP), pulsed electric fields (PEF), irradiation, light treatments, microwave sterilization, and active and modified atmosphere packaging. This book discusses packaging implications for these nonthermal processing techniques, mild food preservation methods and other hurdle technologies.

NONTHERMAL PROCESSING

Conventional thermal methods for food processing applications are stove‐top cooking, blanching, pasteurization and retorting. These are designed to inactivate microorganisms, enzymes, and other chemical reactions, as well as achieve the expected shelf life and food safety. Chemical and physical changes taking place in foods during conventional heat treatments have been well documented in the published literature. Numerous practical applications of thermal treatments in a wide range of foods have been used from early ages to current times. Additionally, natural interactions and chemical reactions occurring in thermally processed foods and packaging materials are well known. However, in order to better understand and identify the physical, chemical and mechanical interactions taking place within foods and packaging materials exposed to nonthermal treatments, more studies are needed. These will provide data that can be used by engineers and food scientists as they seek to optimize these nonthermal technologies.

Prior to writing this book, the authors reviewed information about nonthermal processing techniques such as HPP, irradiation and PEF, that were reported in the FSTA‐Food Science Technology Abstract database (https://www.ifis.org/fsta). As seen in Figure 1.1, the numbers of nonthermal processing publications have continuously increased from 2001 to 2016, especially in topics relating to HPP and irradiation. Recent studies on HPP, irradiation, and PEF technologies have extensively focused on improving the functionality, safety and fresh tasting qualities of a wide range of foods in response to consumers’ demands. These publication trends also reported on recent developments and improvements to these technologies. As a result, various foods and beverages are now commercially treated by HPP and irradiation, and are in retail trade in various markets around the world.

Graph, with three ascending curves, illustrating increasing of HPP (solid square), irradiation (solid circle), and pulsed electric field (light circle) researches from 2001 to 2016. — **Figure 1.1** Increasing of HPP, irradiation, and pulsed electric field researches from 2001 to 2016 (https://www.ifis.org/fsta).

High pressure processing is a nonthermal preservation technique that uses high pressured water or another appropriate liquid to transfer the pressure to a food product, either by itself or in its primary package. Microorganisms and enzymes are inactivated by this high pressure treatment, and this helps to maintain the safety and shelf stability of the food. The high pressure process is considered nonthermal due to its ability to inactivate pathogenic and food spoilage microorganisms without causing significant changes to the fresh‐like qualities, sensory attributes or nutrients of the food. This is done without the use of heat normally generated by conventional thermal treatments such as retort processing, for example. Recent trends have shown that a growing consumer interest in HPP is due to its ability to extend the shelf life of food products without the addition of chemical preservatives. Thus, HPP provides benefits to food companies by helping them to meet the requirements for “clean label claims” for their packaged food products. The clean label claim is a recent trend driven by consumers and it relates to their concerns about too much synthetic chemicals being in processed foods.

Two types of irradiation techniques are currently used in food processing. These include ionizing and nonionizing radiations. Ionizing radiation works by using high energy to remove electrons from atoms and it produces ionization as a result. Examples of these include x‐rays, alpha and beta particles, and gamma rays. Ionization can be initiated by radioactive elements such as uranium, radium, tritium, carbon‐14, and polonium, or by high voltage generators that produce x‐rays. Currently, beta particles and gamma rays obtained from cobalt‐60 and cesium‐137 are used for industrial food irradiation applications. Ionization radiation is utilized to inactivate detrimental microorganisms and reduce the rate of spoilage in selected foods. Conversely, nonionizing radiation has a much lower energy level than ionizing radiation. However, nonionizing radiation that is used to treat food, causes atoms within the molecules to vibrate. This vibration produces heat which raises the temperature of the food. Microwave and infrared heating are examples of these. Food irradiation is associated with nonthermal processing due to its ability to inactivate microorganisms, kill insects, and other types of infestation, by using significantly lower temperatures when compared with conventional heat treatments.

Pulsed electric field is a processing technique which uses a high voltage pulse to treat a substrate positioned between two electrodes. Only pumpable liquid or semi‐liquid foods which can flow between the two electrodes can be treated by this technique. During the treatment, harmful microorganisms can be inactivated by the application of micro to millisecond pulses of high voltages to the product that is pumped in the gap between the electrodes. In batch applications, a static treatment can be employed by exposure of the product to the pulsed electric field in a chamber designed with two electrodes. The PEF treatment, due to its extremely short processing time and insignificant increase in temperature, sustains freshness, sensory and nutritional qualities much better than commonly used industrial conventional heat processes such as retorting or microwave cooking.

In general, due to its relatively mild preservation methodology, nonthermally processed foods provide better nutritional and organoleptic characteristics when compared with similar conventionally heated products. Nonthermal processing techniques are also capable of producing safe and extended shelf life foods by inactivating enzymes, and killing pathogenic and spoilage microorganisms.

FACTORS TO BE CONSIDERED DURING NONTHERMAL PROCESSING

Bacilllus stearothermophilus is currently used as a microorganism indicator to estimate standard thermal treatment parameters. Other spore forming microorganisms are also used to validate other suitable thermal processes and food applications with extreme pH, water activity, and/or solute concentrations. To assist with these validation studies, food engineers have developed and used standardized data tables showing the values for D (time) and Z (temperature) for the reduction of standard microorganisms. The effectiveness of the thermal treatment on the organisms is determined by the F‐value. However, the resistances of standard microorganisms to nonthermal treatments are different when compared with their responses to conventional thermal techniques. This makes the validation of nonthermal techniques a more challenging feat. Hence this is the reason why more research on nonthermal techniques is needed. In some cases, nonthermal processing can be a replacement for conventional heat treatments, at least, partially, by combining the nonthermal process with heat and or chemical treatments, and other hurdle technologies, depending on nature of the food. However, a better understanding of the effects of nonthermal techniques on chemical and physical changes and of microbiological inactivation in processed products is still needed in order to bridge the gaps between research achievements and industrial applications. Table 1.1 summarizes the process considerations, benefits, and shortcomings of nonthermal processing methods relevant to food products (Neetoo and Chen, 2014).

Table 1.1 List of process consideration, benefits, and shortcoming of alternative nonthermal processing methods (reprinted from Neetoo and Chen, 2014, pp. 145–147).

Process	Process considerations	Benefits	Shortcomings	Examples of applications
High hydrostatic pressure	Processing time	Enhances product safety	Equipment is cost‐prohibitive	Fruit products
	Treatment temperature	Extends shelf life of product	Phenomenon of “tailing” during microbial inactivation	Yogurts
	Pressure level	Desirable textural changes possible	Changes in sensory quality possible	Smoothies
	Product acidity	Production of “novel” products	Not suitable for foods with air spaces	Condiments
	Water activity	Minimal effect on flavor, nutrients and pigment compounds	Not suitable for dry foods	Salad dressings
	Physiological age of target organisms	Minimal textural loss in high‐moisture foods	Refrigeration needed for low‐acid foods	Meats and vegetables
	Product composition	Can eliminate spores when combined with high temperature	Elevated temperatures and pressures required for spore inactivation	Sauces
	Vessel size	In‐container and bulk processing possible		High‐value commodities such as seafood
	Packaging material integrity	Potential for reduction or elimination of chemical preservatives
	Processing aids	Positive consumer appeal
		No evidence of toxicity of HHP alone
Pulsed electric field	Electric field intensity	Effective against vegetative bacteria	Not suitable for non‐liquid foods	Fruit juices
	Chamber design	Relatively short processing time	Postprocess recontamination possible	Milk
	Electrodes design	Suitable for pumpable foods	Less effective against enzymes and spores	Whole liquid egg
	Pulse width	Minimal impact on nutrients, flavor or pigment compounds	Adverse electrolytic reactions could occur	Soups
	Treatment time	No evidence of toxicity	Not currently energy efficient	Heat‐sensitive foods
	Temperature		Restricted to foods with low electrical conductivity
	Microbial species		Not suitable for product that contain bubbles
	Microbial load		Scaling up of process difficult
	Physiological age of organisms
	Product acidity
	Product conductivity
	Presence of antimicrobials
Ultraviolet light/pulsed UV light	Transmissivity of product	Short processing time	Shadowing effect possible with complex surfaces	Bread
	Geometric configuration of reactor	Minimal collateral effects on foods	Has low penetration power	Cakes
	Power	Low energy input	Ineffective against spores	Pizza
	Wavelength	Suitable for high‐and low‐moisture foods	Possible adverse sensory effects at high dosages	Fresh produce
	Physical arrangement of source	Amenable for postpackage processing	Possible adverse chemical effects	Meats
	Product shape/size	Medium cost	Reduced efficacy with high microbial load	Seafood
	Product flow profile		Possible resistance in some microbes	Cheeses
	Radiation path length		Reliability of equipment to be established	Food packages
	Combination with other hurdles
Ultrasound	Amplitude of ultrasonic waves	Ultrasound effective against vegetative cells	Has little effect on its own	Any food that is heated
	Exposure time	TS and MTS effective against vegetative cells and spores	Challenges with scaling up
	Microbial species	Reduced process times	Free radicals could damage product quality
	Volume of food	Amenable to batch and continuous processing	Can induce undesirable textural changes
	Product composition	Little adaptation required for existing processing plant	Can be damaging to eyes
	Treatment temperature	Possible modification of food structure and texture	Can cause burns and skin cancer
		Energy efficient	Depth of penetration affected by solids and air in product
		Several equipment options	Potential problems with scaling up of plant
		Effect on enzyme activity
		Can be combined with other unit operations
Ionizing radiation	Absorbed dose	Long history of use	High capital cost	Fresh produce
	Water activity	High penetration power	Localized risks from radiation	Herbs and spices
	Freezing	Suitable for sterilization (food and packages)	Hazardous operation	Packaging materials
	Prevailing oxygen	Suitable for postpackage processing	Poor consumer acceptance	Meat and fish
	Microbial load	Suitable for nonmicrobiological applications (e.g. sprout inhibition)	Changes of flavor due to oxidation
	Microbial species	Packaged and frozen foods can be treated	Loss of nutritional value
	Product composition	Low operating costs	Development of radiation‐resistant mutants
	State of food	Can be scaled up	Microbial toxins could be present
	Food thickness	Low and medium dose has minimal effect on product quality	Outgrowth of pathogens
	Particle size	Suitable for low‐and high‐moisture foods
	Combination with other hurdles	Diverse applications

PACKAGING FOR NONTHERMAL PROCESSING

The main goal of food packaging is the storage, preservation and protection of the product for an extended period of time. The objective is to ensure the quality and safety of the product for convenient consumption when desired by the consumer. Besides these primary functions, other required functions are the effective marketing and distribution of the product, in addition to consumer matters such as obtaining information about the commodity, efficient and convenient handling, dispensing, and sales promotion. The significance of these packaging functions can shift from one aspect to another according to the needs of society and the lifestyle of consumers, plus the emergence of new technologies.

For nonthermally treated foods, the nature of the packaging and its design should be carefully selected in order to ensure the success of the specific technology. In addition to these, consideration must be given to the process parameters and mechanisms, the microbial growth kinetics, and the mechanical and physical properties of the packaging materials and systems. Food products treated by HPP are usually prepackaged within individual flexible or semi‐rigid packaging materials, or could be packaged in bulk after the treatment. The prepackaged processing method is essential during batch HPP treatments. In this process, the packaging and the material, of which it is made, will be exposed to the same HPP as the food, and must be designed with the ability to survive the pressure treatment. This means that the package must be designed to survive the water‐mediated high hydrostatic pressures which typically range from 30‐600 MPa, but could be as high as 800 MPa. Since the application of pressure will result in volume changes according to the laws of physics, the reversible response of the whole package to the compression/decompression process during HPP is crucial to the successful commercialization of this non‐thermal processing technology. Plastics are the best choice of material for HPP food packaging because they are flexible and most have excellent water‐resistant properties.

The microbicidal purpose of radiating food will be lost if the safety and the shelf life of the treated product is not maintained after the irradiation process. This is facilitated by packaging the food prior to the irradiation process. This ensures that the food remains sterile during transportation, storage and handling prior to consumption. Irradiation applied to prepackaged foods will also expose the packaging material to the radiation treatment. This means that the selection of the packaging material must be of such that minimal changes to the molecular structure are caused by the irradiation. Severe changes to the chemical or morphological composition of the material could accelerate an unsafe release of chemical additives from the package to the food. As a result, the United States Food and Drug Administration (FDA) has published a list of approved packaging materials, additives and the irradiation doses for food processing operations.

Since PEF treated products are not prepackaged before exposure to the electric field, the packaging material does not come in contact with the electrical energy. However, at the end of the PEF process, the product must be aseptically packaged for extended shelf life. To accomplish this, the packaging material must be sterilized by dry heat, steam, ultra violet light, chemicals, and/or a combination of these methods. Not only must the material survive these sterilization methods, any residual sterilant must be removed from the package prior to filling it with the PEF treated food. The packaging material must also be compatible with the product and not allow the migration of undesirable substances, odors, and flavors to the foods, in addition to maintaining its safety and quality.

CONSUMER PREFERENCE OF PACKAGING DESIGN AND REGULATION OF NONTHERMAL PROCESSING

An aesthetically appealing package influences consumers’ purchasing decisions, and it serves as a strategic marketing tool. A good comprehension of consumer preferences for package design is important for the marketing success of the product. However, package design must not compromise the proper material selection because this could impact the safety and quality of the nonthermal product. Nonthermal processing operations, packaging methods, and materials in contact with the food must be used in accordance with permitted governmental regulations. As an example, the Radura logo is required on the labels of most irradiated packaged foods. Also, a list of packaging materials and the dosages approved for food irritation in the United States are shown in Table 1.2 (FDA, 2015).

Table 1.2 Packaging materials and adjuvants approved for irradiation by the U.S. Food and Drug Administration (FDA).

Maximum Radiation Dose (kGy)	Types of Packaging Materials and Adjuvants Approved for Irradiation
0.5	Kraft paper to contain only flour
7.2	Polystyrene foam tray
10	Nitrocellulose‐coated cellophane; Glassine paper;
	Wax‐coated paperboard;
	Polyolefin film;^a
	Polystyrene film;^a
	Rubber hydrochloride film;^a
	Vinylidene chloride‐vinyl chloride copolymer film;^a Vinylidene chloride copolymer‐coated cellophane; Nylon 11; Optional adjuvants for polyolefin films plus optional vinylidene chloride copolymer coating; PET film plus optional adjuvants, vinylidene chloride copolymer and polyethylene coatings
30	Ethylene‐vinyl acetate copolymers
60	Vegetable parchments; Polyethylene film;^a Polyethylene terephthalate film;^a Nylon 6 film;^a Vinyl chloride‐vinyl acetate copolymer film;^a

^a Plus limited optional adjuvants

In summary, the packaging of a nonthermally processed food is subject to a combination of the nature of the corresponding nonthermal technology, the response of the packaging material to the nonthermal process, regulatory guidelines, consumer acceptance, and the economic analysis of the nonthermal method for the specific food product. Therefore, business studies relating to nonthermal processing and packaging methods should be both technical and socio‐economical.

REFERENCES

FDA. 2015. U.S. regulatory requirements for irradiating foods. http://www.fda.gov/Food/IngredientsPackagingLabeling/IrradiatedFoodPackaging/ucm110730.htm (accessed September 16, 2016).
Min, S., Zhang, Q.H., and Han, J.H. 2005. Packaging for non‐thermal food processing. In: Innovations in Food Packaging, J. H. Han (Ed.) Elsevier Academic Press. pp. 482–500.
Neetoo, H. and Chen, H. 2014. Alternative food processing technologies. In: Food Processing: Principles and Applications, Second Edition. S. Clark et al. (Eds.) John Wiley & Sons, Ltd. pp. 137–169.

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Packaging for Nonthermal Processing of Food

Second Edition

**Titles in the IFT Press series**