Food Toxicants Analysis

by Picó

• ISBN13: 9780444528438
• ISBN10: 0444528431
• Edition: 1st
• Format: Hardcover
• Copyright: 2007-02-07
• Publisher: Elsevier Science

Summary

Food Toxicants Analysis covers different aspects from the field of analytical food toxicology including emerging analytical techniques and applications to detect food allergens, genetically modified organisms, and novel ingredients (including those of functional foods). Focus will be on natural toxins in food plants and animals, cancer modulating substances, microbial toxins in foods (algal, fungal, and bacterial) and all groups of contaminants (i.e., pesticides), persistent organic pollutants, metals, packaging materials, hormones and animal drug residues. The first section describes the current status of the regulatory framework, including the key principles of the EU food law, food safety, and the main mechanisms of enforcement. The second section addresses validation and quality assurance in food toxicants analysis and comprises a general discussion on the use of risk analysis in establishing priorities, the selection and quality control of available analytical techniques. The third section addresses new issues in food toxicant analysis including food allergens and genetically modified organisms (GMOs). The fourth section covers the analysis of organic food toxicants. * step-by-step guide to the use of food analysis techniques * eighteen chapters covering emerging fields in food toxicants analysis * assesses the latest techniques in the field of inorganic analysis

Table of Contents

Preface	p. v
Contents list	p. vii
Contributor contact details	p. xxi
Regulations
The international regulation of chemical toxicants in food: Codex Alimentarius	p. 1
General principles of Codex Alimentarius	p. 1
Operation of Codex Alimentarius	p. 2
Decision making and enforcement mechanisms in Codex Alimentarius	p. 4
Codex standard for contaminants and toxins in foods Codex Stan 193 1995 (Rev. 1-1977)	p. 4
Scope	p. 4
Definition terms	p. 4
Contaminant	p. 4
Natural toxins	p. 5
Maximum Level	p. 5
General principles regarding contaminants in food	p. 5
General	p. 5
Principles for establishing maximum levels (MLs) in foods and feeds	p. 6
Specific criteria	p. 6
Codex procedure for establishing standards for contaminants in food	p. 6
Procedure for preliminary discussion about contaminants in the CCFAC	p. 6
Procedure for risk management decisions in the CCFAC regarding contaminants	p. 6
Format of the standard for contaminants in food	p. 7
Types of presentation for the standards	p. 7
Food categorization system	p. 7
Description of the food categorization system of the GSC	p. 7
Review and revision of the standard	p. 8
Other codex standards and guidelines regarding contaminants in food	p. 8
Different legislations on toxicants in foodstuffs	p. 11
Food toxicant and Food safety	p. 11
Nature of toxicants	p. 11
Occurrence and control of toxicants along the food chain	p. 11
European Union	p. 12
The EU White Paper on Food Safety	p. 13
Food toxicants as addressed in the "new" EU food hygiene legislation and related legal texts	p. 15
Legal texts dealing with specific substances with possible or factual adverse health effects	p. 18
Toxins of bacterial origin	p. 18
Contaminants, residues, food additives and substances formed during food processing	p. 19
Legal requirements for detection methods	p. 22
USA	p. 23
Historical aspects	p. 23
Organizational framework	p. 24
Principles of food safety	p. 25
Specific legislation	p. 26
Mercosur legislation	p. 27
Asia-Pacific Region	p. 29
Concluding Remarks	p. 29
Risk and Quality Assurance
Risk assessment of food additives and contaminants	p. 33
Risk assessment procedures	p. 33
The need for risk assessment	p. 33
Hazard identification and characterisation	p. 34
Use of animal tests	p. 34
Use of epidemiology data	p. 36
Use of other data	p. 36
Dose considerations	p. 37
Exposure assessment	p. 37
Risk characterization	p. 38
The issue of carcinogens	p. 39
Methods for evaluating the risk from 'data poor' additives and contaminants	p. 40
Regulation of food additives and contaminants	p. 42
Overall conclusions on the risk assessment process	p. 42
The case of Sunset Yellow	p. 43
Food dyes and their regulation	p. 43
Sunset Yellow FCF	p. 44
Hazard identification and chaiacterization - animal findings	p. 45
Human data	p. 46
Assessment of intake	p. 46
Consideration of Sudan1 - a contaminant of Sunset Yellow	p. 47
Sudan 1. Hazard identification and characterization	p. 47
Sudan 1. Risk characterization	p. 48
Future of food risk assessment	p. 49
Societal trends	p. 49
The future challenge for risk assessment	p. 50
Training needs	p. 50
Quality Assurance	p. 53
Introduction	p. 53
European Union - Food Control Directives	p. 53
Codex Alimentarius Commission	p. 56
Accreditation	p. 57
Internal quality control: harmonised guidelines for internal quality control in analytical chemistry laboratories	p. 58
Basic concepts	p. 58
Scope of the guidelines	p. 60
Internal quality control and uncertainty	p. 60
Recommendations in the guidelines	p. 61
Proficiency testing	p. 63
What is proficiency testing?	p. 63
Why proficiency testing is important?	p. 64
ISO/IUPAC/AOAC International harmonised protocol for proficiency testing of (chemical) analytical laboratories	p. 64
Organization of proficiency testing schemes	p. 64
Methods of analysis	p. 68
AOAC International (AOACI)	p. 69
The European Union	p. 69
The Codex Alimentarius Commission	p. 69
Principles for the establishment of Codex methods of analysis	p. 70
European Committee for Standardization (CEN)	p. 71
Requirements of official bodies for methods of analysis	p. 72
Collaborative trials	p. 73
What is a collaborative trial?	p. 73
IUPAC/ISO/AOAC International harmonisation protocol	p. 73
The components that make up a collaborative trial	p. 74
Assessment of the acceptability of the precision characteristics of a method of analysis	p. 76
Summary requirements for a collaborative trial	p. 77
Harmonised guidelines for single-laboratory validation of methods of analysis	p. 78
Recovery factors: development of an internationally agreed protocol for the use of recovery factors	p. 78
Sources of error in analytical chemistry	p. 80
International guidelines	p. 81
Recommendations	p. 81
Measurement uncertainty	p. 81
Conclusions	p. 82
Methods of analysis being developed or published by the European Committee for standardisation (CEN) in areas of relevance to this text	p. 84
Codex guidelines on measurement uncertainty	p. 88
Molecular Biology Techniques	p. 7
Immunoassays	p. 91
Overview of immunoassays	p. 91
Advantages of immunoassays	p. 91
Disadvantages of immunoassays	p. 93
Principles of immunoassay	p. 98
Development of immunoassay for food contaminants	p. 99
Hapten synthesis	p. 99
Selection of space arms and the point of attachment	p. 101
Coupling procedures to carrier protein, enzyme and antibodies	p. 104
Carboxylic groups-mixed function anhydride	p. 104
Carboxylic groups-carbodiimide	p. 105
Carboxylic groups-N-hydroxysuccinimide	p. 106
Miscellaneous carboxylic methods	p. 107
Hydroxyl groups	p. 109
Amines	p. 110
Carbonyl, phenols and thiol groups	p. 113
Bifunctional reagents	p. 115
Antibody production	p. 115
Polyclonal antibodies	p. 116
Monoclonal antibodies	p. 117
Recombinant antibodies	p. 117
Immunoassay formats	p. 118
Immobilization	p. 121
Antibody characterization	p. 123
Sensitivity and limit of detection	p. 125
Specificity	p. 126
Matrix effect	p. 127
Assay accuracy	p. 129
Assay precision	p. 131
Quality assurance and quality control	p. 132
Reagent stability	p. 133
Conclusion	p. 133
Polymerase chain reaction (PCR)	p. 147
Introduction	p. 147
Qualitative PCR	p. 149
Multiplex PCR	p. 149
Nested PCR	p. 150
Reversed transcription PCR	p. 151
Quantification with PCR	p. 152
Quantitative conventional PCR techniques	p. 152
Relative quantitative PCR	p. 153
Absolute quantitative PCR	p. 153
PCR with clamping	p. 153
Quantitative PCR based on the 'Real-Time PCR' system	p. 155
SYBR Green I chemistry	p. 155
TAMRA quenched TaqMan probes	p. 156
Other types of probes	p. 160
High throughput genotyping with PCR	p. 161
Restriction fragment length polymorphism (RFLP) of PCR-amplified fragments	p. 161
Other genetic markers	p. 162
Array systems	p. 162
New trends in genotyping	p. 162
Micro Total Analytical Systems ([mu]TAS)	p. 162
Single molecule PCR	p. 163
Immobilized PCR and DNA colonies	p. 163
Good assay	p. 163
Arrayed Primer Extension (APEX)	p. 163
Fluorescent Amplified Fragment Length Polymorphism (FAFLP)	p. 164
Analysis of toxicants	p. 164
Food allergens	p. 165
Mycotoxins and bacterial toxins	p. 169
Fungal contaminants	p. 170
Bacterial contaminants	p. 172
Identification of genetically modified organisms (GMOs)	p. 177
Predictive toxicogenomics	p. 178
Conclusions and future trends	p. 181
Analysis of food allergens. Practical applications	p. 189
Introduction	p. 189
Methods for the detection of allergens	p. 194
Rast/East inhibition	p. 194
Immunoblotting	p. 194
Rocket immuno-electrophoresis	p. 195
Elisa	p. 195
Dipsticks	p. 197
Biosensors	p. 197
PCR	p. 198
Cell response factor release assay	p. 200
Proteomics	p. 201
A selection of food allergens and their detection	p. 202
Peanuts	p. 202
Characteristics of peanut allergy	p. 202
Peanut allergenic proteins	p. 202
Peanut detection methods	p. 202
Comparisons/validation of commercial peanut detection kits	p. 205
Milk and dairy products	p. 207
Characteristics of milk allergy	p. 207
Milk allergenic proteins	p. 207
Milk detection methods	p. 208
Eggs and egg products	p. 210
Characteristics of egg allergy	p. 210
Eggs allergens	p. 210
Egg detection methods	p. 211
Crustaceans	p. 212
Characteristics of crustacean allergy	p. 212
Crustacean allergens	p. 212
Crustacean detection methods	p. 213
Fish	p. 213
Characteristics of fish allergy	p. 213
Fish allergens	p. 214
Fish detection methods	p. 214
Conclusions	p. 215
Case studies	p. 215
Summary and outlook	p. 216
Sampling, detection, identification and quantification of genetically modified organisms (GMOs)	p. 231
Introduction	p. 231
Genetically modified organisms (GMOs)	p. 231
GMOs on the world market	p. 233
The analytical procedure	p. 235
Analyte relationships and associated characteristics	p. 237
Sampling	p. 238
Analyte purification	p. 240
Characterising GMOs	p. 243
DNA sequence based characterisation	p. 243
RNA based characterisation	p. 244
Protein based characterisation	p. 245
Metabolite based characterisation	p. 245
Detecting GMO derived analytes	p. 246
Establishing the GM quantity	p. 246
The unit of measurement and expression of GM content	p. 249
Protein based detection methods	p. 249
RNA based detection methods	p. 250
Metabolite based detection methods	p. 250
DNA based detection methods	p. 251
Target specificity	p. 251
Technologies applied to DNA based GMO detection	p. 254
Qualitative detection methods	p. 255
Quantitative detection methods	p. 256
Detection and quantification limits	p. 259
Reference materials	p. 260
Method validation and performance reliability	p. 261
Concluding remarks	p. 263
Screening and Chromatographic Methods
Extraction procedures	p. 269
Introduction	p. 269
Analyte extraction from liquid foodstuff	p. 269
Liquid-liquid extraction	p. 269
Solid-phase extraction	p. 271
Techniques based on sorptive extraction	p. 274
Solid-phase microextraction	p. 275
Stir-bar sorptive extraction	p. 277
Supported liquid membranes	p. 278
Analyte extraction from solid foodstuff	p. 279
Soxhlet extraction	p. 280
Liquid-phase extraction	p. 280
Supercritical fluid extraction	p. 281
Microwave-assisted extraction	p. 284
Pressurized liquid extraction	p. 286
Matrix solid-phase dispersion	p. 288
Clean-up and fractionation methods	p. 299
Introduction	p. 299
Nature of interferences	p. 300
Methods based on partitioning	p. 304
Conventional liquid-liquid partitioning	p. 304
Ion-pair partitioning	p. 306
Other liquid-liquid partitioning approaches	p. 307
Methods based on chromatography	p. 308
Adsorption chromatography clean-up	p. 309
Partition chromatography clean-up	p. 311
Ion-exchange chromatography clean-up	p. 314
Size-exclusion chromatography clean-up	p. 317
Clean-up based on molecular recognition	p. 319
Immuno-based clean-up	p. 319
Molecular imprinting clean-up	p. 327
Co-distillation/forced volatilisation methods	p. 333
Precipitation clean-up methods	p. 334
Chemical clean-up methods	p. 336
Final remarks	p. 337
Automated clean up techniques	p. 349
Introduction	p. 349
Scope	p. 349
Reasons for clean up in food analysis	p. 350
Rational of automated clean up	p. 354
Reasons to automate clean up	p. 354
Reasons not to automate clean up	p. 355
To automate or not?	p. 355
Relative backwardness of automation in food toxicant analysis	p. 356
Approaches for automated clean up: off-line vs on-line	p. 357
Automated off-line clean up approaches	p. 359
SFE and PLE	p. 359
GPC	p. 362
SPE	p. 364
HPLC	p. 368
On-line clean up approaches	p. 372
Clean up coupled to GC	p. 372
Headspace techniques	p. 372
Automated combined extraction/clean-up with GC analysis	p. 374
Automated membrane based clean up	p. 376
Automated clean up in the GC inlet	p. 378
SPE-GC	p. 380
GPC-GC	p. 380
LC-GC	p. 383
LCxGC	p. 386
GC-GC	p. 386
Comprehensive GCxGC	p. 386
Clean up coupled to LC	p. 390
Combined extraction/clean up coupled to LC	p. 390
SPE-HPLC	p. 393
LC-LC (column switching)	p. 410
LCxLC	p. 410
Concluding remarks	p. 411
Gas chromatography-mass spectrometry (GC-MS)	p. 419
Introduction	p. 419
Matrix effects	p. 420
Sample introduction	p. 426
Split/splitless injection	p. 427
Cold on-column (COC) injection	p. 428
Programmable temperature vaporisation injection (PTV)	p. 429
Direct sample introduction (DSI)/ Difficult matrix introduction (DMI)	p. 432
Solid-phase microextraction (SPME)	p. 434
Gas chromatographic separation	p. 434
Fast GC	p. 436
Practical approaches to fast GC analysis	p. 437
Instrumental requirements in fast GC	p. 440
Multidimensional high resolution GC	p. 444
Comprehensive two-dimensional gas chromatography (GCxGC)	p. 446
GCxGC set-up	p. 446
Optimisation of operation conditions and instrumental requirements in GCxGC	p. 446
Application of GCxGC, examples of merits	p. 450
Mass spectrometric detection	p. 454
Ionisation techniques	p. 454
Electron ionisation (EI)	p. 454
Chemical ionisation (CI)	p. 455
Mass analysers	p. 456
Quadrupole instruments	p. 457
Ion-trap instruments	p. 457
Time-of-flight instruments	p. 459
Double-focusing magnetic sector instruments	p. 459
Tandem mass spectrometry	p. 460
Applications of GC-MS to food toxicants analysis	p. 463
Pesticides	p. 463
Polychlorinated biphenyls (PCBs)	p. 464
Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs), dioxine-like polychlorinated biphenyls and dioxine-like PCBs	p. 465
Polybrominated diphenyl ethers (PBDEs)	p. 466
Polycyclic aromatic hydrocarbons (PAHs)	p. 469
Mycotoxins	p. 470
Veterinary drug residues	p. 470
Acrylamide	p. 470
Chloropropanols	p. 471
Liquid chromatography with conventional detection	p. 475
Introduction	p. 475
Separation modes for food toxicant analysis	p. 476
Detection systems	p. 476
UV-VIS detection	p. 476
Fluorescence detection	p. 486
Electrochemical detection	p. 495
On-line combination of multiple detectors	p. 499
Conclusion	p. 499
Liquid chromatography-mass spectrometry	p. 509
Introduction	p. 509
Liquid chromatographic separation	p. 510
Interfacing systems	p. 518
Matrix effects	p. 523
Mass analyzers	p. 528
Single quadrupole	p. 528
Time-of-flight	p. 531
Tandem mass analyzers	p. 535
Triple quadrupole	p. 535
Quadrupole ion trap	p. 539
Hybrid Quadrupole time-of-flight	p. 543
Applications	p. 545
Pesticide residues	p. 545
Veterinary drugs	p. 546
Food packaging migrating products	p. 548
Mycotoxins	p. 548
Algae and fish toxins	p. 549
Heat induced decomposition products	p. 549
Food additives	p. 550
Toxic food constituents	p. 551
Conclusions and future trends	p. 551
Capillary electrophoresis	p. 561
Introduction	p. 561
Principles of capillary electrophoresis	p. 561
The driving force in the capillary: the electroosmotic flow (EOF)	p. 563
The theory of zone electrophoresis for charged colloids and molecules	p. 565
The most important techniques in brief	p. 566
Capillary zone electrophoresis (CZE)	p. 566
Micellar electrokinetic chromatography (MEKC)	p. 567
Chiral CZE and chiral MEKC	p. 568
Capillary gel electrophoresis (CGE)	p. 569
Capillary electrochromatography (CEC)	p. 569
Application of capillary electrophoresis in food analysis	p. 570
CZE methods for food contaminants and components	p. 571
Veterinary drugs	p. 571
Pesticides	p. 575
Biological origin toxins	p. 575
Inorganic ions and low molecular weight acids	p. 580
Amines and amino acids	p. 581
Phenolic compounds and vitamins	p. 583
Carbohydrates	p. 584
Proteins	p. 584
MEKC methods for food contaminants and components	p. 586
Pesticides and toxins	p. 586
Amino acids, additives and proteins	p. 587
Chiral CZE and chiral MEKC for food contaminants and components	p. 588
Pesticides	p. 588
Low molecular weight acids	p. 591
CGE methods for food contaminants and components	p. 591
CEC methods for food contaminants and components	p. 592
Conclusions and future trends	p. 592
Sensors, biosensors and MIP based sensors	p. 599
Introduction	p. 599
Chemosensor and biosensors: basis and fundamentals	p. 601
Chemosensors	p. 605
pH sensors	p. 605
Electronic noses	p. 606
Electronic tongues	p. 608
Biosensors	p. 610
Transduction elements in food biosensors	p. 611
Recognition element classification and biosensors for food toxicant analysis	p. 615
Enzyme biosensors	p. 615
Immunosensors	p. 617
Microbial biosensors	p. 622
Commercial instrumentation and future perspectives	p. 622
Biomimics: molecularly imprinted polymers (MIPs)	p. 623
Development and application of MIP-based sensors	p. 623
MIPs in preparation/preconcentration and separative applications	p. 626
Development and application of MIP-based sensors	p. 627
Future trends	p. 627
Atomic absorption spectroscopy	p. 637
Introduction	p. 637
Theory of atomic absorption spectroscopy	p. 637
Atomic absorption spectrophotometers	p. 638
Interferences	p. 639
Spectral interferences (background absorption)	p. 640
Instrumental background correction	p. 640
Non-spectral interferences	p. 640
Nonspectral interferences in flame	p. 641
Nonspectral interferences in ETAAS	p. 642
Miscellaneous sample introduction systems	p. 644
Solid sampling	p. 644
Slurry method	p. 645
Determination of toxic metals	p. 646
Some toxic elements and their properties	p. 648
Sample mineralization and mineral analysis in food	p. 650
Ash, decomposition/digestion procedures	p. 651
Dry ashing	p. 652
Wet ashing	p. 653
Low temperature plasma ashing	p. 653
Microwave digestion	p. 654
Electrochemical stripping analysis of trace and ultra-trace concentrations of toxic metals and metalloids in foods and beverages	p. 667
Introduction	p. 667
Principles of electrochemical stripping analysis	p. 668
Stripping voltammetry	p. 668
Anodic stripping voltammetry	p. 669
Cathodic stripping voltammetry	p. 672
Adsorptive cathodic stripping voltammetry	p. 674
Stripping potentiometric analysis	p. 677
Potentiometric stripping analysis	p. 677
Constant current stripping analysis	p. 679
Adsorptive constant current stripping analysis	p. 679
Analytical applications of stripping analysis to foods and beverages	p. 680
Animal tissues, fruits, vegetables and non-dairy products	p. 681
Sugar	p. 686
Milk and milk products	p. 687
Fruit juice and soft drinks	p. 687
Alcoholic beverages	p. 688
Other food related materials	p. 690
Interferences in stripping analysis	p. 691
Conclusions and future trends	p. 693
Inductively coupled plasma-mass spectrometry (ICP-MS)	p. 697
Introduction	p. 697
Description of the technique	p. 698
Principles of ICP-MS	p. 698
Instrumentation	p. 703
Quadrupoles	p. 704
Sector field analysers	p. 708
TOF analysers	p. 709
Sample introduction	p. 710
Interferences	p. 717
Comparison with other atomic spectrometric techniques	p. 724
Analysis of toxic elements and elemental species in food	p. 725
Element determination	p. 725
Sample treatment	p. 725
Applications	p. 727
Hyphenated techniques for element speciation	p. 731
Hyphenated techniques for element speciation	p. 731
Sample treatment	p. 733
Applications	p. 735
Conclusions and future trends	p. 743
Index	p. 753
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