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- Herausgeber: John Wiley & Sons
- Kategorie: Fachliteratur
- Sprache: Englisch
FOOD SAFETY, PLASTICS AND SUSTAINABILITY A unique book by a well-known polymer scientist on a subject that is trending in plastics engineering. This book focuses on plastics for food safety, materials, chemicals and methods, as well as the applications of these polymers. The book begins with a chapter on food safety. Here, food security and the issues of migration of substances from packaging into the corresponding food, as well as the impact of microplastics on humans and the environment are discussed. In the next chapter, regulations, standards, and specifications are detailed. In another chapter, testing methods, such as risk assessment, freshness testing of food, and food colorants are discussed. In the chapter entitled "Food Packaging", the methods that can be used for these issues are given as well as the special materials for food packaging. The chapter on materials includes a discussion on nanocomposites, biopolymers, microplastics, and edible films. This is followed by chapters on additives and applications, such as functional food applications. The final chapter covers the identification of the materials, the methods for recycling, plastic waste generation, and post-consumer polyolefins. Three separate indexes ensure a reader/user-friendly experience.
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Veröffentlichungsjahr: 2023
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Table of Contents
Cover
Series Page
Title Page
Copyright Page
Preface
1 Food Safety
1.1 Food Security
1.2 Migration of Substances from Packaging
1.3 Food Safety and Hygiene
1.4 Impact of Microplastics on Humans and the Environment
1.5 Methods of Food Packaging
1.6 Recycling Safety
References
2 Regulations
2.1 European Strategy for Plastics
2.2 Basic Principles of Packaging
2.3 Colorants and Optical Brighteners
2.4 Non-intentionally Added Substances in Food Contact Material
2.5 Recycling
2.6 Standards
References
3 Testing Methods
3.1 Risk Assessment
3.2 Antimicrobial Packaging
3.3 Food Colorants
3.4 Standards
References
4 Food Packaging
4.1 Automated Method
4.2 Multilayer Packaging
4.3 Flexible Packaging
4.4 Multicomponent Package
4.5 Chlorine Dioxide Gas-Releasing Package
4.6 Sustainable Food Packaging
4.7 Ventable Food Packages
4.8 Packages for Pourable Food
4.9 Food Storage
4.10 Special Materials for Food Packaging
References
5 Materials
5.1 Nanocomposites
5.2 Biopolymers
5.3 Microplastics
5.4 Single-Use Materials
5.5 Edible Films
References
6 Additives
6.1 Chemical Additives
6.2 Mathematical Models
6.3 Evaluation of Models
6.4 Plastic Additives by Swelling
6.5 Fatty Acid Amide
6.6 Perfluorinated Compounds
6.7 Toxic Materials in Plastics
6.8 Aflatoxins
6.9 Migration of Additives from Plastics into Food
6.10 Marine Environments
6.11 Surfactants
6.12 Salting-Out Agents
References
7 Applications
7.1 Glaze-Like Coatings
7.2 Functional Food Applications
7.3 Prevention of Oxidation
7.4 Heterocyclic Aromatic Amines in Prepared Food
7.5 Radiation-Curable Compositions
7.6 Antimycotics
References
8 Recycling
8.1 Identification of the Materials
8.2 Recycling Methods
8.3 Post-Consumer Polyolefins
8.4 Plastic Waste Generation
8.5 Recycled Plastics in Food Contact
References
Index
Also of Interest
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Known diseases (19).
Table 1.2 1,2-Dihydroquinoxaline derivates.
Table 1.3 Contaminants in microplastics (24).
Table 1.4 Polychlorinated biphenyl compounds.
Table 1.5 Polycyclic aromatic hydrocarbons.
Table 1.6 Organochlorine pesticides.
Table 1.7 Brominated diphenyl ethers.
Chapter 2
Table 2.1 Standards.
Chapter 3
Table 3.1 Substances in the analyzed recycled LDPE sample.
Table 3.2 Chitosan-based intelligent packaging films (6).
Table 3.3 ASTM Standards (2).
Chapter 4
Table 4.1 Nucleating agents.
Table 4.2 Barrier properties of petroleum and bio-based paper coatings.
Table 4.3 Principal film-forming biodegradable classes of substances used in p...
Table 4.4 Estimated lethal doses for SAF-1 (82).
Table 4.5 Estimated lethal doses for DLB-1 (82).
Table 4.6 Types of antimicrobial packaging materials (47).
Table 4.7 Antimicrobial activity of chitosan TNPs (125, 128).
Table 4.8 Natural polymers for multilayer films (131).
Chapter 5
Table 5.1 Production of biodegradable and non-biodegradable bioplastics (33, 3...
Table 5.2 Bioactive molecules.
Chapter 6
Table 6.1 Most commonly used additives in plastic materials (4).
Table 6.2 Additives used for migration measurements (12).
Table 6.3 Migration materials.
Table 6.4 Perfluorinated compounds.
Table 6.5 List of primary aromatic amines.
Chapter 7
Table 7.1 Flavonoid compounds in vine tea extract (10, 11).
Table 7.2 Isoflavone compounds in vine tea extract (16).
Table 7.3 Antioxidation composition (28).
Table 7.4 Natural antioxidants (29).
Table 7.5 Methods for the extraction of natural antioxidants (33).
Table 7.6 Antimicrobial agents for polymeric matrices (72).
Chapter 8
Table 8.1 General properties of food packaging materials (13).
Table 8.2 Amount of migrants (16).
Table 8.3 Migration as function of time (16).
Table 8.4 Materials applied for multi-material multilayer plastic packaging (5...
List of Illustrations
Chapter 1
Figure 1.1 Xenoestrogens.
Figure 1.2 d10-Benzophenone.
Figure 1.3 Biogenic amines.
Figure 1.4 1,2-Dihydroquinoxaline derivates.
Figure 1.5 Polychlorinated biphenyl compounds.
Figure 1.6 Polycyclic aromatic hydrocarbons.
Figure 1.7 Organochlorine pesticides.
Figure 1.8 Sphinganine.
Figure 1.9 Estrogenic metabolites.
Figure 1.10 Brominated diphenyl ethers.
Figure 1.11 Asparagine.
Figure 1.12 Formation of acrylamide (56).
Figure 1.13 L-Tryptophan.
Figure 1.14 Xanthine derivates.
Figure 1.15 12-
o
-Tetradecanoyphorbol-13-acetate.
Figure 1.16 Ethylenediaminetetraacetic acid.
Figure 1.17 Bacteriocins.
Figure 1.18 Oil compounds.
Figure 1.19 Benomyl.
Chapter 2
Figure 2.1 Dichlorobenzidine.
Figure 2.2 Amines and Isocyanates.
Chapter 3
Figure 3.1 Phenol derivatives. Linear and branched PE oligomers. Acetate ester...
Figure 3.2 Color-changing compounds.
Figure 3.3 Compounds for a double-layer indicator film.
Figure 3.4 Coating materials.
Figure 3.5 Rosemarinic acid.
Figure 3.6 Thiobarbituric acid.
Chapter 4
Figure 4.1 Recyclable flexible package (5).
Figure 4.2 Perspective view of a lower container (9)
Figure 4.3 Perspective view of an upper container (9).
Figure 4.4 Cross-sectional view of an upper container (9).
Figure 4.5 Organic substances for nucleating agents.
Figure 4.6 Bio-based label/insert package (19).
Figure 4.7 Sealed package for pourable food products (37).
Figure 4.8 Tray (Full view) (39).
Figure 4.9 Tray (Side view) (39).
Figure 4.10 Storage container (40).
Figure 4.11 Food storage system (41).
Figure 4.12 Chemicals for toxicity measurement.
Figure 4.13 Antimicrobial agents.
Figure 4.14 Halloysite and Hydroxyapatite.
Figure 4.15 Compounds for inclusion complex.
Chapter 5
Figure 5.1 Optical enhancing agents (8).
Figure 5.2 Bioactive molecules.
Figure 5.3 Cinnamaldehyde.
Figure 5.4 Compounds for modified starch.
Figure 5.5 Hexadecyltrimethoxysilane.
Figure 5.6 Antimicrobial additives.
Figure 5.7 Catechin.
Figure 5.8 Pectin and pullulan.
Figure 5.9 Anisidine.
Chapter 6
Figure 6.1 Plasticizers. Curing agents. Biocides. Blowing agents.
Figure 6.2 Additives for migration measurements.
Figure 6.3 Compounds for migration tests.
Figure 6.4 Fatty acid amides.
Figure 6.5 Perfluorinated compounds.
Figure 6.6 Naturally occurring aflatoxins.
Figure 6.7 2,4,7,9-Tetramethyl-5-decyne-4,7-diol.
Figure 6.8 Dansyl chloride.
Figure 6.9 Biogenic amines.
Figure 6.10 Aromatic amines.
Chapter 7
Figure 7.1 Coating from HDPE in water (1).
Figure 7.2 Coating from HDPE in cottonseed oil (1).
Figure 7.3 Bioactive compounds in Kokum.
Figure 7.4 Compounds in citrus fruits.
Figure 7.5 Flavonoid compounds in vine tea extract.
Figure 7.6 Isoflavone compounds in vine tea extract.
Figure 7.7 1,2-Diacylglycerol.
Figure 7.8 Acids for antioxidation composition (28).
Figure 7.9 Natural antioxidants.
Figure 7.10 2-Amlno-1-methyl-6-phenylimidazo[4,5-b]pyrldine.
Figure 7.11 2-Amino-1,6-dimethylfuro[3,2-e]imidazo[4,5-b]pyridine.
Figure 7.12 Heterocyclic aromatic amines.
Figure 7.13 Antimicrobial agents.
Chapter 8
Figure 8.1 Phthalates and phthalic acids.
Figure 8.2 Di(2-ethylhexyl) adipate and di(2-ethylhexyl) phthalate.
Figure 8.3 Method for separating multilayer systems (31).
Figure 8.4 Wetting agents.
Figure 8.5 Closed-loop continuous system for recycling food service ware (51).
Figure 8.6 Contaminants.
Guide
Cover Page
Series Page
Title Page
Copyright Page
Preface
Table of Contents
Begin Reading
Index
Also of Interest
WILEY END USER LICENSE AGREEMENT
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Scrivener Publishing100 Cummings Center, Suite 541JBeverly, MA 01915-6106
Publishers at ScrivenerMartin Scrivener ([email protected])Phillip Carmical ([email protected])
Food Safety, Plastics and Sustainability
Materials, Chemicals, Recycling and the Circular Economy
Johannes Karl Fink
Montanuniversität Leoben, Austria
This edition first published 2023 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA© 2023 Scrivener Publishing LLCFor more information about Scrivener publications please visit www.scrivenerpublishing.com.
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions.
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For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com.
Limit of Liability/Disclaimer of WarrantyWhile the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchant-ability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials, or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read.
Library of Congress Cataloging-in-Publication Data
ISBN 978-1-394-17456-0
Cover image: Pixabay.comCover design by Russell Richardson
Preface
This book focuses on plastics for food safety and materials and chemicals, methods and applications of these polymers.
The book begins with a chapter about food safety. Here, food security and the issues of migration of substances from packaging into the corresponding food are discussed.
Then, in the next chapter, regulations, standards, and specifications are detailed. Furthermore, in another chapter, testing methods, such as risk assessment, freshness testing of food, and food colorants are discussed.
In the chapter entitled “Food Packaging,” the methods that can be used for these issues are given. Also, materials, special uses, and finally, methods for recycling are given.
The subsequent chapters and their subject matter are:
Chapter 1: Food Safety
Chapter 2: Regulations
Chapter 3: Testing Methods
Chapter 4: Food Packaging
Chapter 5: Materials
Chapter 6: Additives
Chapter 7: Applications
Chapter 8: Recycling
The text focuses on the literature of the past decade. Beyond education, this book will serve the needs of industry engineers and specialists who have only a passing knowledge of the plastics and composites industries but need to know more.
How to Use This Book
Utmost care has been taken to present reliable data. Because of the vast variety of material presented here, however, the text cannot be complete in all aspects, and it is recommended that the reader study the original literature for more complete information.
The reader should be aware that mostly US patents have been cited where available, but not the corresponding equivalent patents in other countries. For this reason, the author cannot assume responsibility for the completeness, validity or consequences of the use of the material presented herein. Every attempt has been made to identify trademarks; however, there were some that the author was unable to locate.
Index
There are three indices: an index of acronyms, an index of chemicals, and a general index.
In the index of chemicals, compounds that occur extensively, e.g., ‘acetone,’ are not included at every occurrence, but rather when they appear in an important context.
Acknowledgements
I am indebted to our university librarians, Dr. Christian Hasenhüttl, Margit Keshmiri, Friedrich Scheer, Christian Slamenik, Renate Tschabuschnig, and Elisabeth Groß for their support in literature acquisition. I also want to express my gratitude to all the scientists who have carefully published their results concerning the topics dealt with herein. This book could not have been otherwise compiled.
Last, but not least, I want to thank the publisher, Martin Scrivener, for his abiding interest and help in the preparation of the text. In addition, my thanks go to Jean Markovic, who made the final copyedit with utmost care.
Johannes Fink
Wiener Neustadt, January 6, 2023
1Food Safety
With the world’s growing population, the provision of a safe, nutritious and wholesome food supply for all has become a major challenge (1). To achieve this, effective risk management based on sound science and unbiased information is required by all stake-holders, including the food industry, governments and consumers themselves. In addition, the globalization of the food supply requires the harmonization of policies and standards based on a common understanding of food safety among authorities in countries around the world. With some 280 chapters, the Encyclopedia of Food Safety provides unbiased and concise overviews which form in total a comprehensive coverage of a broad range of food safety topics, which may be grouped under the following general categories (1):
History and basic sciences that support food safety,
Foodborne diseases, including surveillance and investigation,
Foodborne hazards, including microbiological and chemical agents,
Substances added to food, both directly and indirectly,
Food technologies, including the latest developments,
Food commodities, including their potential hazards and controls,
Food safety management systems, including their elements and the roles of stakeholders.
The Encyclopedia provides a platform for experts from the field of food safety and related fields, such as nutrition, food science and technology and environment, to share and learn from state-of-the art expertise with the rest of the food safety community (1).
Plastic plays a significant and growing role in modern day society, delivering many benefits, particularly in food safety and preservation, and can help to reduce food waste (2).
Advances in packaging can not only reduce losses but also improve food quality and safety. To offer the best food protection the FAO suggests that a packaging solution could include more, but better packaging, rather than less packaging.
A novel approach for food safety, which integrates a statistical study and subjective discussion, was adopted to review the recent advances in the environment and food safety (3).
Here, a scientometric-based statistical study was conducted based on 4904 publications collected from the Web of Science Core Collection database. It was found that the research on the environment and food safety grew steadily from 2001 to 2020. The statistical analysis of most-cited papers, titles, abstracts, keywords, and research areas revealed that the research on the environment and food safety was diverse and multidisciplinary.
In addition to the scientometric study, strategies to protect the environment and ensure the safety of food were critically discussed, followed by a discussion on the emerging research topics, including emerging contaminates, e.g., microplastics, rapid detection of contaminants, e.g., biosensors, and environmentally friendly food packaging materials, e.g., biodegradable polymers (3).
1.2 Migration of Substances from Packaging
The usage of new food packaging materials has increased the number of occurring hazards due to the migration from packaging material to the packaged food (5). Although polymers have mainly monopolized the interest of migration testing and experimentation, recent studies have revealed that migration also occurs from traditional materials generally considered to be safe, such as paper, carton, wood, ceramic, and metal. The regulations and the directives of the EU tend to become stricter in this respect.
The emphasis is on reaching a consensus in terms of food simulants and testing conditions for migration studies. Furthermore, the list of hazardous monomers, oligomers, and additives continues to be augmented in order to ensure that the consumer safety is in current agreement with the hazard analysis critical control points (HACCP), which is continuously gaining ground (5).
Food and beverages can be very aggressive chemical milieu and may interact strongly with materials that they touch (6). Whenever food is placed in contact with another substance, there is a risk that chemicals from the contact material may migrate into the food. These chemicals may be harmful if ingested in large quantities, or impart a taint or odor to the food, thereby negatively affecting the food quality. Food packaging is the most obvious example of a food contact material. As the demand for prepackaged foods increases, so might the potential risk to consumers from the release of chemicals into the food product.
Chemical Migration and Food Contact Materials reviews the latest controls and research in this field and how they can be used to ensure that food is safe to eat.
In a monograph, the regulation and quality control of chemical migration into food are discussed (6). Then, the latest developments in areas such as exposure estimation and analysis of food contact materials are reviewed. Finally, specific chapters on major food contact materials and packaging types are presented, such as recycled plastics, metals, paper and board, multilayer packaging and intelligent packaging.
The large number of synthetic materials that are used for the manufacture of packages makes the evaluation of the food package interactions complicated (7).
Different parameters, such as the nature of the food of interest, the type of food package contact, the time and temperature of contact, the packaging materials used, the properties of the migrating substances, as well as the amount of potential migrants contained in the packaging materials, can drastically affect the migration rate and the extent of migration.
Due to the extreme variety of foods used, several food simulants have been suggested and applied for testing the migration phenomenon under various laboratory conditions (7). The use of many of those simulants is defined by national and international legislation. The main migration phenomena, which are related to the most commonly used packaging materials, have been detailed (7). In the study, it was clearly demonstrated that the complexity of the migration phenomena requires more research to establish internationally accepted risk management procedures and standardized testing methods.
1.2.1 Modeling of Migration
The potential for the use of migration modeling for studying poly-olefin packaging materials, such as low-density and high-density poly(ethylene) and poly(propylene), was summarized and demonstrated with practical examples (8).
For these polymers, an upper limit of migration into foodstuffs can be predicted with a high degree of statistical confidence. The only analytical information needed for modeling in such cases is the initial concentration of the migrant in the polymer matrix.
For polyolefins of unknown origin or newly developed materials with new properties, a quick experimental method has been described for obtaining the characteristic matrix parameter needed for the process of migration modeling.
For easy handling of both the experimental results and the diffusion model, a user-friendly software has been developed. An additional aim of the described method is the determination of the migrant partition between polymer and food or food simulant and the specific contribution of the migrant molecular structure on the diffusion coefficient. For migration modeling of packaging materials with multilayer structures, a numerical solution of the diffusion equation is described. This procedure has also been applied for modeling the migration into solid or high-viscosity foodstuffs (8).
The permeation through and diffusion/migration from high-density poly(ethylene), poly(butylene), poly(propylene) and crosslinked poly(ethylene) films was investigated experimentally with three different methods to determine diffusion coefficients in these polyolefins for a series of additives, their degradation products and other organic substances in the 20°C to 60°C temperature range (9).
The experimental methods used were dynamic permeation through additive-free polymer films, kinetic desorption from additivated films into water and kinetic migration from additivated into additive-free polymer films. It was found that in general the temperature dependence of the obtained diffusion coefficients was well represented by the Arrhenius law.
Some of these results also suggested that the contact of the polyolefins with water had an influence on the magnitude of the diffusion coefficients and on their apparent activation energy of diffusion (9).
The migration of phthalate from PET bottles containing non-alcoholic beer was done by performing an adaptive neuro-fuzzy inference system analysis (10).
The data showed that the storage temperature, contact surface and storage period correlate with the rate of migration. The migration of phthalate increases with storage duration gradually and re- duces under different temperatures and contact surface. Moreover, increased temperature and storage duration resulted in an increase in migration level ranging from 0.6 µg l−1 to 2.9 µg l−1 (10).
The study used an adaptive neuro-fuzzy inference system analysis architecture, which consists of three inputs (temperature, surface and storage period), Gaussian-bell membership functions for each input variable and one output layer, which represent the migration level. The validation and training models showed an excellent match between the experimental and predicted values of adaptive neuro-fuzzy inference system analysis.
The analysis of the model showed that adaptive neuro-fuzzy inference system analysis is a powerful tool for predicting phthalate migration from bottles containing non-alcoholic beer (10).
1.2.2 Sample Pretreatment Methods
An excessive absorption of migrating substances from food contact materials can affect human health. Thus, it is essential to analyze the migration of contaminants from food contact materials (11).
However, comprehensive analysis has been challenged by low concentration of migrating substances and manifold and complex matrix interference of food contact materials. Therefore, appropriate sample pretreatment methods should be applied before instrumental detection, which is essential to improve the analytical efficiency, sensitivity, and reliability.
The development of sample pretreatment methods for the analysis of migrating substances from food contact materials has been reviewed in the past decade (11). To extract volatile and semi-volatile substances, headspace extraction, headspace solid phase microextraction, and a purge and trap technique are discussed here.
For non-volatile substances, solid-liquid extraction and field-assisted extraction are usually used to extract them from food contact materials; while liquid-liquid extraction, solid phase extraction, and their corresponding microextraction techniques play important roles in the enrichment process (11).
Also, new progress in the development of sample pretreatment methods of food contact materials was summarized, covering new devices, specific adsorbents, and sample preparation methods for rapid detection (11).
1.2.3 Special Chemicals
1.2.3.1 Styrene
Poly(styrene) (PS) is extensively used in diverse forms for packaging of many food products such as meat, dairy and bakery products. There is a potential migration of styrene monomer from PS packages into the foods which are in contact with them (12).
The representative styrene migration from PS packaging material into the corresponding foods was detailed. Also, the addressed parameters affecting the styrene migration were discussed. The analytical methods for detecting the styrene monomer in food products and PS packaging materials was also covered in the study. The possible safety and health issues related to the styrene monomer migration were also covered.
The quality of PS packaging materials in terms of their styrene monomer residue level and the storage conditions of foods can greatly affect styrene migration. Also, the food characteristics, such as fat content and pH, can significantly affect the migration of styrene. Although styrene is considered a nontoxic compound, its migration into foods can downgrade sensorial properties as well as result in health problems. In some cases, the presence of styrene in foods can cause carcinogenic, hematological, cytogenetic, and neurotoxic issues (12).
A sensitive, accurate and fast headspace-solid phase microextraction-gas chromatography-tandem mass spectrometry (HS-SPME-GC-MS/MS) method was developed and validated for the determination of styrene in various food matrices. The mean recovery ranged from 90% to 116% with a relative standard deviation of =11% (13).
This method was used for the determination of the concentration of styrene in 23 foodstuffs packed in PS containers, as well as the levels of styrene migrating into various foods (water, milk, cheese or cream) from 14 tableware or kitchenware articles made of styrene plastics. All samples were collected from the Greek market in 2020.
The concentrations of styrene in the packaged foods ranged from 0.4 to 160 ng g−1, with the highest concentration found in a meat product packed in a foamed PS tray. It is worth noting that 56% of PS packaged dairy products and desserts had a styrene concentration of higher than 10 ng g−1. Particularly high levels of styrene that have not previously been reported, of up to 46 ng g−1, were found in dairy products for children. The highest level of styrene migration from tableware or kitchenware articles, 89 ng g−1, was observed when disposable cups from foamed PS were filled with milk at 70°C for 2 h (13).
1.2.3.2 Bisphenol A
Bisphenol A is mainly used in the production of poly(carbonate), a material with high durability and strength. This chemical is also used in the production of epoxy resins, applied in the coating of metal surfaces in contact with food. Moreover, it is employed in thermal paper (14).
Bisphenol A has been widely reported by the media, being the aim of diverse scientific studies, since it is a xenoestrogen with a chemical structure identical to that of β-estradiol, which allows it to interact with human estrogen receptors. These compounds are shown in Figure 1.1.
Figure 1.1 Xenoestrogens.
Bisphenol A monitoring is essential to avoid a potential health risk of the population. The European Union has recently updated the specific migration limit for bisphenol A at 0.05 mgkg−1 of food.
Regarding the levels of migration determined in different types of food contact materials, it was found that, despite the great majority of studies showing positive samples, none of them exceeded the value of specific migration limit established by the European Union at the time of the studies (14).
1.2.3.3 Benzophenone
Benzophenone may be present in cartonboard food-packaging materials as a residue from UV-cured inks and lacquers used to print on the packaging (15). It may also be present if the cartonboard is made from recycled fibers recovered from printed materials.
A method has been developed to test for benzophenone in cartonboard packaging materials and to test the migration levels in foodstuffs.
Here, the packaging material is extracted with a solvent containing d10-benzophenone as the internal standard. Foods are extracted with solvent containing d10-benzophenone and the extract is defatted using hexane. The extracts are analyzed by gas chromatography (GC)-mass spectroscopy (MS). d10-Benzophenone is the deuterium labeled benzophenone. It is shown in Figure 1.2.
Figure 1.2 d10-Benzophenone.
For the analysis of food, the limit of detection was 0.01 mgkg−1 and the limit of quantification was 0.05 mgkg−1. The calibration was linear from 0.05 mgkg−1 to 20 mgkg−1. The method for food analysis was validated in-house and it also returned satisfactory results in a blind check-sample exercise organized by an independent laboratory.
The methods were applied to the analysis of 350 retail samples that used printed cartonboard packaging. A total of 207 (59%) packaging samples had no significant benzophenone (<0.05 mg dm−2). Seven (2%) were in the range 0.05 mg dm−2 to 0.2 mg dm−2, 60 (17%) were from 0.2 mg dm−2 to 0.8 mg dm−2 and 76 (22%) were from 0.8 mg dm−2 to 3.3 mg dm−2.
A total of 71 samples were then selected at random from the 143 packaging samples that contained benzophenone, and the food it- self was analyzed. Benzophenone was detected in 51 (72%) of the foods. Two food samples (3%) were in the range 0.01 mgkg−1 to 0.05 mg kg−1. A total of 29 (41%) were from 0.05 mgkg−1 to 0.5 mg kg−1, 17 (24%) were from 0.5 mg kg−1 to 5 mg kg−1 and three (4%) food samples exceeded 5 mg kg−1. The highest level of benzophenone in food was 7.3 mg kg−1 for a high-fat chocolate confectionery product packaged in direct contact with cartonboard, with room temperature storage conditions and with a high contact area:food mass ratio. When the mass fraction of the migration of benzophenone was calculated for the different contact and storage regimes involved, the attenuation effects of indirect contact and of low temperature storage were cumulative. Thus, there was a sixfold reduction in migration for indirect contact compared with direct contact, a sixfold reduction for chilled/frozen storage compared with ambient storage, and 40-fold reduction for the two contact conditions combined (15).
1.2.3.4 Perfluorochemicals
Perfluorochemicals are widely used in the manufacturing and processing of a vast array of consumer goods, including electrical wiring, clothing, household and automotive products. Furthermore, relatively small quantities of perfluorochemicals are also used in the manufacturing of food contact substances that represent potential sources of oral exposure to these chemicals (16).
The most recognizable products to consumers are the uses of perfluorochemicals in non-stick coatings (poly(tetrafluoroethylene) (PTFE)) for cookware and also their use in paper coatings for oil and moisture resistance. Recent epidemiology studies have demonstrated the presence of two particular perfluorochemicals, perfluorooctane sulfonate and perfluorooctanoic acid, in human serum at very low part per billion levels. These perfluorochemicals are biopersistent and are the subject of numerous studies investigating the many possible sources of human exposure. Among the various uses of these two chemicals, perfluorooctane sulfonate is a residual impurity in some paper coatings used for food contact and perfluorooctanoic acid is a processing aid in the manufacture of PTFE used for many purposes, including non-stick cookware.
Very little information is available on the types of perfluorochemicals that have the potential to migrate from perfluoro coatings in- to food. One obstacle to studying the migration is the difficulty in measuring perfluorochemicals by routine conventional analytical techniques such as GC/MS or LC-UV. Many perfluorochemicals used in food contact substances are not detectable by these conventional methods. As liquid chromatography-mass spectrometry (LC/MS) develops into a routine analytical technique, potential migrants from perfluoro coatings can be more easily characterized. In a study, data is presented on the types of perfluorochemicals that are used in food packaging and cookware. Additionally, research is presented on the migration or potential for migration of these chemicals into foods or food-simulating liquids.
The results from migration tests show mg kg−1 amounts of perfluoro paper additives/coatings transfer to food oil. Analysis of PTFE cookware shows residual amounts of perfluorooctanoic acid in the low µg kg−1 range. Perfluorooctanoic acid is present in microwave popcorn bag paper in amounts as high as 300 µg kg−1 (16).
1.2.4 Safety of Recycled HDPE and PP
An analytical protocol was set up and successfully applied to study the food safety of recycled high-density poly(ethylene) (HDPE) and PP crates (17). A worst-case scenario was applied that focused not only on overall migration and specific migration of accepted starting materials but also on migratable degradation products of polymers and additives that may be formed during mechanical recycling.
The analytical protocol was set up to cover a wide variety of possible migrants. Identification and semi-quantification were possible for almost all migrants that increased significantly with increasing mechanical recycling steps for both the HDPE and PP crates.
It was concluded that the analytical protocol was suitable to study the influence of (multiple) recycling on the food safety of plastic materials. The protocol can be applied to other plastic foodcontact materials and provides valuable information on the food safety of the recycling process and the resulting recycled foodcontact materials in addition to challenge testing (17).
1.3 Food Safety and Hygiene
Food hygiene is the conditions and measures necessary to certify the safety of food from production to consumption. Food can become contaminated at any point during slaughtering or harvesting, processing, storage, distribution, transportation and preparation.
All conditions and measures that are required during production, processing, storage, distribution and preparation of food to ensure that it is safe, wholesome and fit for human consumption were defined in 1984 by the World Health Organization (WHO).
A lack of requisite food hygiene can lead to foodborne diseases and death of the consumer. Foodborne illness has been associated with improper storage or reheating (50%), food stored inappropriately (45%) and cross contamination (39%). Proper food preparation can prevent most foodborne diseases.
More than 200 known diseases can be transmitted through food (18). Some of these diseases are collected in Table 1.1.
Table 1.1 Known diseases (19).
Disease or Agent
Bacterial
Bacterial
Bacillus cereus
Botulism, foodborne
Brucella
spp.
Campylobacter
spp.
Clostridium perfringens
Escherichia coli
Listeria monocytogenes
Salmonella typhi
Salmonella
, nontyphoidal
Shigella
spp.
Staphylococcus
Vibrio cholerae
Vibrio vulnificus
Yersinia enterocolitica
Parasitic
Parasitic
Cryptosporidium parvum
Cyclospora cayetanensis
Giardia lamblia
Toxoplasma gondii
Trichinella spiralis
Viral
Viral
Norwalk-like viruses
Rotavirus
Astrovirus
Hepatitis A
Hazard analysis and critical control points is a systematic preventive approach to food safety from biological, chemical, and physical hazards in production processes that can cause the finished product to be unsafe and designs measures to reduce these risks to a safe level. Food hygiene and safety usually refer to contamination with microorganisms or microbes.
1.3.1 Sensors for Amine Detection
Biogenic amines are good indicators of food freshness because they are products of microbial fermentation (20). In the process of food spoilage, microbes break down amino acids via deaminization to generate ammonia, and via decarboxylation to generate biogenic amines such as cadaverine, putrescine, spermidine, spermine, and others. These amines are shown in Figure 1.3.
Figure 1.3 Biogenic amines.
These biogenic amines not only signal food spoilage, but also have an adverse impact on human health and physiological functions. Thus, monitoring biogenic amines in food is important both because the chemical species can have toxic effects, and because they signify food spoilage by microbes. When compared to time-temperature indicators, which only respond to temperature changes, a system detecting the presence of biogenic amines offers a more direct method of monitoring food safety and hygiene.
Aggregation-induced emission (AIE) active chemosensors exhibit a change for UV-vis absorption and become non-luminescent upon protonation (20). Upon deprotonation, the chemosensors revert to their original absorption and emission. This deprotonation process can be triggered in the presence of amines, and specifically, biogenic amines. So, the chemosensors can detect amine species, e.g., biogenic amines produced during food fermentation, quickly and with a high sensitivity.
As chemicals, 1,2-dihydroquinoxaline derivates can be used (20, 21).
Some derivates are shown in Table 1.2 and Figure 1.4.
Table 1.2 1,2-Dihydroquinoxaline derivates.
Compound
3-Methyl-2-prop-2-enyl-1,2-dihydroquinoxaline
3-Methoxy-6-(trifluoromethyl)-1,2-dihydroquinoxaline
2-Phenyl-1,2-dihydroquinoxaline
3-Phenyl-1,2-dihydroquinoxaline
3-Phenyl-1,2-dihydroquinoxaline-2-carboxylic acid
3-Methyl-2-propan-2-yl-1,2-dihydroquinoxaline
5-[6-[4-(Trifluoromethyl)phenyl]pyrimidin-4-yl]oxy-1,2-dihydroquinoxaline
5-Bromo-3-[4-(trifluoromethyl)phenyl]-1,2-dihydroquinoxaline
3-[Chloro(phenyl)methyl]-1,2-dihydroquinoxaline
3-(1H-Indol-3-yl)-1,2-dihydroquinoxaline
6-Chloro-1,2-dihydroquinoxaline
3-(3-Nitrophenyl)-1,2-dihydroquinoxaline
Ethyl 7-amino-3-ethoxy-6-(trifluoromethyl)-1,2-dihydroquinoxaline-2-carboxylate
8-Amino-2-ethyl-5-(hydroxymethyl)-1,2-dihydroquinoxaline-6-carboxylic acid
2,3-Dimethyl-1,2-dihydroquinoxaline
2-Chloro-3-(5-chloro-1H-pyrazol-3-yl)-1,2-dihydroquinoxaline
2-Bromo-5-[6-[4-(trifluoromethyl)phenyl]pyrimidin-4-yl]oxy-1,2-dihydroquinoxaline
1.4 Impact of Microplastics on Humans and the Environment
Micro- and nanoplastics have the potential to be transferred between trophic levels and, therefore, the risk characterization and the assessment of dietary exposure to them constitutes a current challenge for food safety alongside the study of the role of plastics as vectors of other contaminants and pathogenic microorganisms (22).
Figure 1.4 1,2-Dihydroquinoxaline derivates.
The risk posed by microplastics to humans and the environment, has become a hot topic (23). The concern is focused not only on the effect of microplastics as such but also on additives and chemical contaminants absorbed by microplastics that may be released and negatively affect animals and environmental health. Despite several works having been written on this topic, a number of knowledge gaps still should be filled to enable a correct risk assessment of this important issue. For example, the relevance of microplastics for food safety has not yet been fully established and scientific results aimed at establishing a possible health risk for contaminants associated with microplastics are rather controversial. The risk assessment of microplastics in foodstuff is still at a very early stage and very few studies on the monitoring of microplastics in foodstuff and their effects on human health are available. Additionally, it is difficult to compare results from different studies as methodologies and study designs are not uniform. For this reason, it is not always possible to reach some definitive conclusion (23).
Studies have shown high concentrations of chemical contaminants that adsorb microplastics from the surrounding environment (24).
The compounds are listed in Table 1.3.
Table 1.3 Contaminants in microplastics (24).
1.4.1 Polychlorinated Biphenyl Compounds
Details of polychlorinated biphenyl compounds are shown in Table 1.4 and in Figure 1.5
Table 1.4 Polychlorinated biphenyl compounds.
Abbreviation
Name
PCB 1
2-Chlorobiphenyl
PCB 2
3-Chlorobiphenyl
PCB 3
4-Chlorobiphenyl
PCB 5
2,3-Dichlorobiphenyl
PCB 7
2,4-Dichlorobiphenyl
PCB 11
3,3’-Dichlorobiphenyl
PCB 12
3,4-Dichlorobiphenyl
PCB 14
3,5-Dichlorobiphenyl
PCB 15
4,4’-Dichlorobiphenyl
PCB 18
2,2’,5-Trichlorobiphenyl
PCB 28
2,4,4’-Trichlorobiphenyl
PCB 29
2,4,5-Trichlorobiphenyl
PCB 31
2,4’,5-Trichlorobiphenyl
PCB 52
2,2’,5,5’-Tetrachlorobiphenyl
PCB 77
3,3’,4,4’-Tetrachlorobiphenyl
PCB 101
2,2’,4,5,5’-Pentachlorobiphenyl
PCB 105
2,3,3’,4,4’-Pentachlorobiphenyl
PCB 138
2,2’,3,4,4’,5’-Hexachlorobiphenyl
PCB 149
2,2’,3,4’,5’,6-Hexachlorobiphenyl
PCB 153
2,2’,4,4’,5,5’-Hexachlorobiphenyl
PCB 170
2,2’,3,3’,4,4’,5-Heptachlorobiphenyl
PCB 180
2,2’,3,4,4’,5,5’-Heptachlorobiphenyl
PCB 209
Decachlorobiphenyl
1.4.2 Polycyclic Aromatic Hydrocarbon Compounds
Fossil fuels and other organic materials formed during incomplete burning can produce and release a complex cluster of emerging pollutants into the environment known as polycyclic aromatic hydrocarbons (25, 26).
Also, human activities have been multiplying the waste and effluents generated in the environment containing different polycyclic aromatic hydrocarbons. All sorts of contaminants including poly- cyclic aromatic hydrocarbons ultimately find their way into the aquatic ecosystem and thereby deplete the quality and standards of the aquatic habitats directly or indirectly (26).
Figure 1.5 Polychlorinated biphenyl compounds.
Details of polycyclic aromatic hydrocarbon compounds are shown in Table 1.5 and in Figure 1.6
Table 1.5 Polycyclic aromatic hydrocarbons.
Name
Name
Benz[a]anthracene
Benzo[b]fluoranthene
Benzo[j]fluoranthene
Benzo[k]fluoranthene
Benzo[a]pyrene
Chrysene
Dibenz[a,h]acridine
Dibenz[a,j]acridine
Dibenz[a,h]anthracene
7H-Dibenz[c,g]carbazole
Dibenzo[a,e]pyrene
Dibenzo[a,h]pyrene
Dibenzo[a,i]pyrene
Indeno[1,2,3-cd]pyrene
Benz[a]anthracene is produced during incomplete combustion of organic matter. It is one of the carcinogenic constituents of tobacco smoke (27).
Also, benzo[j]fluoranthene is present in fossil fuels and is released during the incomplete combustion of organic matter. It has been traced in the smoke of cigarettes, exhaust from gasoline engines, emissions from the combustion of various types of coal and emissions from oil heating, as well as an impurity in some oils such as soybean oil (28).
The primary sources of dibenzopyrenes in the environment are combustion of wood and coal (29), gasoline and diesel exhaust (30), and tires (31). Dibenzo[a,l]pyrene is a constituent of tobacco smoke.
1.4.3 Organochlorine Pesticides
Details of organochlorine pesticides are shown in Table 1.6 and in Figure 1.7
Fungal contamination of animal feed is often unavoidable andis a serious concern given that many of these contaminants include toxic metabolites known as mycotoxins (32). Mycotoxin contamination can occur in a crop growing in the field, or contamination may be introduced during harvesting, storage and/or processing of the animal feed for use in raising monogastric and ruminant animals. Mycotoxins are fairly stable compounds often found in animal feed for monogastric and ruminant animals, and they are a known cause of a wide variety of deleterious effects in these animals. Pesticides are other common contaminants of animal feed. Endotoxins are not natural contaminants of feedstuffs. Feedstuffs can be contaminated with endotoxins when mixed with products of animal origin.
Figure 1.6 Polycyclic aromatic hydrocarbons.
Table 1.6 Organochlorine pesticides.
Name
Name
Aflatoxin
Fumonisin
Ochratoxin
Zearalenone
Figure 1.7 Organochlorine pesticides.
Endotoxins are another type of toxin of bacterial origin, which are commonly found in the gastrointestinal tract of livestock; and pesticides are commonly found in the foodstuffs fed to various types of livestock, and as a result, have been known to have toxic effects on livestock (32).
Mycotoxins are known to cause toxic, teratogenic, mutagenic, and carcinogenic effects, and have been linked to a depression of the animal’s immune system. Furthermore, mycotoxins can affect different organs in an animal, including urinary, digestive, nervous, reproductive, and immune systems, and as such, it makes it more difficult to establish a precise diagnosis once an animal is affected. The effects of mycotoxins depend on the level of contamination, the presence of one or more toxins, the type of animal, its age, the time of exposure, genetic makeup, and its nutritional and health status at the time of exposure to contaminated feed.
The most dangerous mycotoxins affecting poultry are aflatoxin, ochratoxin, T-2 toxin, fumonisin, and deoxynivalenol, also known as DON. These mycotoxins, along with other trichothecene mycotoxins, can also affect monogastric and ruminaNZ amimals, to greater or lesser degrees (32).
1.4.3.1 Aflatoxin
Aflatoxins are various poisonous carcinogens and mutagens that are produced by certain molds, particularly Aspergillus species (33). The fungi grow in soil, decaying vegetation and various staple foodstuffs and commodities such as hay, sweetcorn, wheat, millet, sorghum, cassava, rice, chili peppers, cottonseed, peanuts, tree nuts, sesame seeds, sunflower seeds, and various spices. In short, the relevant fungi grow on almost any crop or food. When such contaminated food is processed or consumed, the aflatoxins enter the general food supply. They have been found in both pet and human foods, as well as in feedstocks for agricultural animals. Animals fed contaminated food can pass aflatoxin transformation products into eggs, milk products, and meat (34).
For example, contaminated poultry feed is the suspected source of aflatoxin-contaminated chicken meat and eggs in Pakistan (35). Children are particularly affected by aflatoxin exposure, which is associated with stunted growth (36), delayed development (37), liver damage, and liver cancer.
An association between childhood stunting and aflatoxin exposure has been reported in some studies but could not be detected in all studies (38).
Adults have a higher tolerance to exposure, but are also at risk. No animal species is immune. Aflatoxins are among the most carcinogenic substances known. After entering the body, aflatoxins may be metabolized by the liver to a reactive epoxide intermediate or hydroxylated to become the less harmful aflatoxin M1.
Aflatoxin poisoning most commonly results from ingestion, but the most toxic aflatoxin compound, B1, can permeate the skin.
The United States Food and Drug Administration (FDA) action levels for aflatoxin present in food or feed is 20 to 300 ppb (39). The FDA has had occasion to declare both human and pet food recalls as a precautionary measure to prevent exposure.
The term aflatoxin is derived from the name of the species Aspergillus flavus, in which some of the compounds first were discovered. The word was coined around 1960 after its discovery as the source of Turkey X disease (40). Aflatoxins form one of the major groupings of mycotoxins, and apart from Aspergillus flavus, various members of the group of compounds occur in species such as Aspergillus parasiticus, Aspergillus pseudocaelatus, Aspergillus pseudonomius, and Aspergillus nomius (41).
1.4.3.2 Fumonisin
The fumonisins are a group of mycotoxins derived from Fusarium of the Liseola section (42). They have strong structural similarity to sphinganine, the backbone precursor of sphingolipids. Sphinganine is shown in Figure 1.8.
Figure 1.8 Sphinganine.
1.4.3.3 Ochratoxin
Ochratoxins are a group of mycotoxins produced by some Aspergillus species (mainly A. ochraceus and A. carbonarius, but also by 33% of A. niger industrial strains) and some Penicillium species, especially P. verrucosum (43). Ochratoxin A is the most prevalent and relevant fungal toxin of this group, while ochratoxins B and C are of lesser importance.
Ochratoxin A is known to occur in commodities such as cereals, coffee, dried fruit, and red wine. It is possibly a human carcinogen and is of special interest as it can be accumulated in the meat of animals. Exposure to ochratoxins through diet can cause acute toxicity in mammalian kidneys. Exposure to ochratoxin A has been associated with Balkan endemic nephropathy, a kidney disease with high mortality in people living near tributaries of the Danube River in Eastern Europe (44).
It has been suggested that carriers of alleles associated with phenylketonuria may have been protected from spontaneous abortion caused by ochratoxin exposure, providing a heterozygous advantage for the alleles despite the possibility of severe intellectual disability in the more rare instance of inheritance from both parents (43).
1.4.3.4 Zearalenone
Zearalenone (ZEN), also known as RAL and F-2 mycotoxin, is a potent estrogenic metabolite produced by some Fusarium and Gibberella species (45). The chemical name of zearalenone is 6-[10-hydroxy-6-oxo-trans-1-undecenyl]-β-resorcyclic acid lactone. Specifically, the Gibberella zeae, the fungal species where zearalenone was initially detected, in its asexual/anamorph stage is known as Fusarium graminearum (46). Several Fusarium species produce toxic substances of considerable concern to livestock and poultry producers, namely deoxynivalenol, T-2 toxin, HT-2 toxin, diacetoxyscir-penol and zearalenone.
In particular, zearalenone is produced by Fusarium graminearum, Fusarium culmorum, Fusarium cerealis, Fusarium equiseti (47), Fusarium verticillioides (48), and Fusarium incarnatum. Zearalenone is the primary toxin that binds to estrogen receptors, causing infertility, abortion or other breeding problems, especially in swine (48). Often, zearalenone is detected together with deoxynivalenol in contaminated samples and its toxicity needs to be considered in combination with the presence of other toxins (49).
Studies in animal models suggest that zearalenone is metabolized primarily to α-zearalenol and β-zearalenol. α-Zearalenolis metabolized predominantly into β-zearalenol and, to a lesser extent, into zearalanone. Some compounds are shown in Figure 1.9.
Figure 1.9 Estrogenic metabolites.
Zearalenone is heat-stable and is found worldwide in a number of cereal crops such as maize, barley, oats, wheat, rice, and sorghum (50–52).
Its production increases when the climate is warm with air humidity at or above twenty percent (48). The environmental pH plays also a role in the toxin’s production. When temperatures fall to 15°C, alkaline soils still support ZEN production. At the preferred Fusarium temperature, which ranges between 25°C and 30°C, neutral pH results in the greatest toxin production (53).
1.4.3.5 Brominated Diphenyl Ethers
Details of brominated diphenyl ethers are shown in Table 1.7 and in Figure 1.10
Table 1.7 Brominated diphenyl ethers.
Abbreviation
Name
BDE 15
4,4’-Dibromodiphenyl ether
BDE 28
2,4,4’-Tribromodiphenyl ether
BDE 36
3,3’,5-Tribromodiphenyl ether
BDE 37
3,4,4’-Tribromodiphenyl ether
BDE 47
2,2’,4,4’-Tetrabromodiphenyl ether
BDE 49
2,2’,4,5’-Tetrabromodiphenyl ether
BDE 66
2,3’,4,4’-Tetrabromodiphenyl ether
BDE 71
2,3’,4’,6-Tetrabromodiphenyl ether
BDE 75
2,4,4’,6-Tetrabromodiphenyl ether
BDE 77
3,3’,4,4’-Tetrabromodiphenyl ether
BDE 85
2,3’,4,4’,6-Pentabromodiphenyl ether
BDE 99
2,2’,4,4’,5-Pentabromodiphenyl ether
BDE 100
2,2’,4,4’,6-Pentabromodiphenyl ether
BDE 119
2,3’,4,4’,6-Pentabromodiphenyl ether
BDE 126
3,3’,4,4’,5-Pentabromodiphenyl ether
BDE 138
2,2’,3,4,4’,5’-Hexabromodiphenyl ether
BDE 153
2,2’,4,4’,5,5-Hexabromodiphenyl ether
BDE 154
2,2’,4,4’,5,6’-Hexabromodiphenyl ether
BDE 181
2,2’,3,4,4’,5,6-Heptabromodiphenyl ether
BDE 183
2,2’,3,4,4’,5’,6-Heptabromodiphenyl ether
BDE 203
2,2’,3,4,4’,5,5’,6-Octabromodiphenyl ether
BDE 205
2,3,3’,4,4’,5,5’,6-Octabromodiphenyl ether
BDE 206
2,2’,3,3’,4,4’,5,5’,6-Nonabromodiphenyl ether
BDE 207
2,2’,3,3’,4,4’,5,6,6’-Nonabromodiphenyl ether
BDE 209
Decabromodiphenyl ether
On the other hand, plastics have additives that are intentionally added during their manufacture to give them color, or other properties, such as flexibility, termoresistance, UV resistance, and fire resistance.
Antimicrobial food packaging incorporating triclosan (5-chloro-2-(2,4-dichlorphenoxy)-phenol) was banned in the European Union in 2010 (54). In other countries, regulations on the use of triclosan in food contact materials are unclear.
In this context, compliance with the EU ban on triclosan was investigated in commercial antibacterial PP food containers sold through online sales platforms. Triclosan was present in all food containers tested. Migration studies to food simulants under different conditions (e.g., conventional and microwave heating, single and repeated use) have been performed according to Regulation 10/2011.
The highest triclosan migration levels corresponded to 95% ethanol at 40ºC for 10 d, although migration rates varied between different containers. Furthermore, microplastics were found to leach from the surface of antibacterial food containers when exposed to microwave heating or oven heating. Therefore, microplastics containing triclosan might enter food in contact with the containers during use, posing a potential health risk for consumers (54).
1.4.4 Carcinogens
1.4.4.1 Carcinogen Contamination
Carcinogen contamination in the food chain, for example, heavy metal ions, pesticides, acrylamide, and mycotoxins, have caused serious health problems (55). A major objective of food safety research is the identification and prevention of exposure to these carcinogens, because of their impossible-to-reverse tumorigenic effects.
However, the detection of carcinogens is difficult because of their trace-level presence in food. Thus, reliable and accurate separation and determination methods are essential to protect food safety and human health.
The state of the art was summarized for separation and determination methods for analyzing carcinogen contamination, especially the advances in biosensing methods. Furthermore, the application of promising technology including nanomaterials, imprinted polymers, and microdevices was detailed (55).
Figure 1.10 Brominated diphenyl ethers.
1.4.4.2 Reduction of Carcinogens
A wide variety of foods have tested positive for the presence of acrylamide (56). Acrylamide has especially been found primarily in carbohydrate food products that have been heated or processed at high temperatures. Examples of foods that have tested positive for acrylamide include coffee, cereals, cookies, potato chips, crackers, french-fried potatoes, breads and rolls, and fried breaded meats.
In general, relatively low contents of acrylamide have been found in heated protein-rich foods, while relatively high contents of acrylamide have been found in carbohydrate-rich foods, compared to non-detectable levels in unheated and boiled foods. Reported levels of acrylamide found in various similarly processed foods include a range of 330-2,300 µg kg1 in potato chips, a range of 300-1100 µg kg1 in french fries, a range of 120-180 µg kg1 in corn chips, and levels ranging from not detectable up to 1400 µg kg1 in various breakfast cereals.
It is believed that acrylamide is formed from the presence of amino acids and reducing sugars. For example, it is believed that a reaction between free asparagine, an amino acid commonly found in raw vegetables, and free reducing sugars accounts for the majority of acrylamide found in fried food products. Asparagine is shown in Figure 1.11. Asparagine accounts for approximately 40% of the total free amino acids found in raw potatoes, approximately 18% of the total free amino acids found in high protein rye, and approximately 14% of the total free amino acids found in wheat.
Figure 1.11 Asparagine.
The most likely route for the formation of acrylamide involves a Maillard reaction (56). The Maillard reaction is a chemical reaction between amino acids and reducing sugars that gives browned food its distinctive flavor. It is named after the French chemist Louis Camille Maillard, who first described it in 1912 while attempting to reproduce biological protein synthesis (57).
The Maillard reaction has long been recognized in food chemistry as one of the most important chemical reactions in food processing and can affect flavor, color, and the nutritional value of the food (56). The Maillard reaction requires heat, moisture, reducing sugars, and amino acids.
The first step of the Maillard reaction involves the combination of a free amino group from free amino acids or proteins, with a reducing sugar, e.g., glucose, to form Amadori or Heyns rearrangement products.
The second step involves the degradation of the Amadori or Heyns rearrangement products via different alternative routes involving deoxyosones, fission, or Strecker degradation. A complex series of reactions, including dehydration, elimination, cyclization, fission, and fragmentation, results in a pool of flavor intermediates and flavor compounds.
The third step of the Maillard reaction is characterized by the formation of brown nitrogenous polymers and copolymers.
Figure 1.12 shows the pathways for the formation of acrylamide starting with asparagine and glucose.
A process and a method for reducing the amount of acrylamide in thermally processed foods has been developed (56). This allows the production of foods with significantly reduced levels of acrylamide.
The method provides a continuous feed of peeled and sliced raw potatoes and contacting the continuous feed of raw potato slices with an aqueous solution at about 60°C for about 5 min to reduce the amount of the acrylamide precursors in the raw potato slices (56).
Using another method, a continuous feed of peeled and sliced raw potatoes, par-frying the raw potato slices at about 171°C to about 182°C until the moisture content is reduced to 3% to 10%, then oven-drying the par-fried slices at less than about 120°C until the moisture content is further reduced to about 1% to 2%. Also, some other methods have been detailed (56).
Figure 1.12 Formation of acrylamide (56).
L-Tryptophan can be applied to a foodstuff to prevent the development of mutagens and carcinogens (58). L-Tryptophan is shown in Figure 1.13. Before cooking of a foodstuff, such as hamburger, L-tryptophan is applied to the surfaces thereof to inhibit the generation of IQ-type carcinogens (58).
Figure 1.13 L-Tryptophan.
The L-tryptophan can be sprinkled on the surface of the foodstuff or incorporated into a sauce which is applied to the foodstuff or put into solution in water (58). The L-tryptophan is preferably applied in an amount greater than the order of magnitude of 1.0 mg cm−2.
For testing, patties with a thickness of 3 mm and 9.6 cm were prepared from 50 g of store-bought 85% lean ground beef using a glass Petri dish cover with 1.5×9.6 cm as a mold. Inhibitor-treated and untreated patties were then either fried or broiled for 5 min.
When the concentration of added L-tryptophan was varied from 1.75 to 140 mM in the complete liquid reflux mode, IQ-type muta-genicity was inhibited, in a dose-dependent fashion, over a range of 15 to 100% (58).
1.4.4.3 Biosensors
Common substances in food can pose a great threat to human health, including foodborne pathogens, heavy metals, mycotoxins, pesticides, herbicides, veterinary drugs, allergens and illegal additives (59). In order to develop rapid, low-cost, portable and on-site detection methods of those contaminants and allergens to ensure food safety, gold nanoparticles of versatile shapes and mor-phologies, such as nanorods, nanoclusters, nanoflowers, nanostars, nanocages, nanobipyramids and nanowires, have been employed as probes because they possess extraordinary properties that can be used to design biosensors that enable the detection of various contaminants and allergens.
