food-analysis-1.pdf

Food Analysis Fourth Edition For other titles published in this series, go to www.springer.com/series/5999 Food Analysis Fourth Edition edited by S. Suzanne Nielsen Purdue University West Lafayette, IN, USA ABC Dr. S. Suzanne Nielsen Purdue Universit...

Food Analysis Fourth Edition For other titles published in this series, go to www.springer.com/series/5999 Food Analysis Fourth Edition edited by S. Suzanne Nielsen Purdue University West Lafayette, IN, USA ABC Dr. S. Suzanne Nielsen Purdue University Dept. Food Science 745 Agriculture Mall Dr. West Lafayette IN 47907-2009 USA [email protected] ISBN 978-1-4419-1477-4 e-ISBN 978-1-4419-1478-1 DOI 10.1007/978-1-4419-1478-1 Springer New York Dordrecht Heidelberg London Library of Congress Control Number: 2010924120 © Springer Science+Business Media, LLC 2010 All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scho- larly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Contents Contributing Authors vii 11. Vitamin Analysis 179 Ronald B. Pegg, W.O. Landen, Jr., Preface and Acknowledgments ix and Ronald R. Eitenmiller List of Abbreviations xi 12. Traditional Methods for Mineral Analysis 201 Robert E. Ward and Charles Part I. General Information E. Carpenter 1. Introduction to Food Analysis 3 S. Suzanne Nielsen Part III. Chemical Properties and Characteristics of Foods 2. United States Government Regulations and International 13. pH and Titratable Acidity 219 Standards Related to Food Analysis 15 George D. Sadler and Patricia S. Suzanne Nielsen A. Murphy 3. Nutrition Labeling 35 14. Fat Characterization 239 Lloyd E. Metzger Sean F. O’Keefe and Oscar A. Pike 4. Evaluation of Analytical Data 53 15. Protein Separation J. Scott Smith and Characterization Procedures 261 Denise M. Smith 5. Sampling and Sample Preparation 69 Rubén O. Morawicki 16. Application of Enzymes in Food Analysis 283 Joseph R. Powers Part II. Compositional Analysis of Foods 17. Immunoassays 301 6. Moisture and Total Solids Analysis 85 Y-H. Peggy Hsieh Robert L. Bradley, Jr. 18. Analysis of Food 7. Ash Analysis 105 Contaminants, Residues, Maurice R. Marshall and Chemical Constituents of Concern 317 Baraem Ismail, Bradley L. Reuhs, 8. Fat Analysis 117 and S. Suzanne Nielsen David B. Min and Wayne C. Ellefson 19. Analysis for Extraneous Matter 351 Hulya Dogan, Bhadriraju 9. Protein Analysis 133 Subramanyam, Sam K. C. Chang and John R. Pedersen 10. Carbohydrate Analysis 147 20. Determination of Oxygen Demand 367 James N. BeMiller Yong D. Hang v vi Contents Part IV. Spectroscopy 28. High-Performance Liquid Chromatography 499 21. Basic Principles of Spectroscopy 375 Bradley L. Reuhs and Mary Ann Michael H. Penner Rounds 22. Ultraviolet, Visible, 29. Gas Chromatography 513 and Fluorescence Spectroscopy 387 Michael C. Qian, Devin G. Michael H. Penner Peterson, and Gary A. Reineccius 23. Infrared Spectroscopy 407 Randy L. Wehling Part VI. Physical Properties of Foods 24. Atomic Absorption 30. Rheological Spectroscopy, Atomic Emission Principles for Food Analysis 541 Spectroscopy, and Inductively Christopher R. Daubert Coupled Plasma-Mass Spectrometry 421 and E. Allen Foegeding Dennis D. Miller and Michael A. Rutzke 31. Thermal Analysis 555 Leonard C. Thomas and Shelly 25. Nuclear Magnetic Resonance 443 J. Schmidt Bradley L. Reuhs and Senay Simsek 32. Color Analysis 573 Ronald E. Wrolstad and Daniel 26. Mass Spectrometry 457 E. Smith J. Scott Smith and Rohan A. Thakur Index...................................................... 587 Part V. Chromatography 27. Basic Principles of Chromatography 473 Baraem Ismail and S. Suzanne Nielsen Contributing Authors James N. BeMiller Y-H. Peggy Hsieh Department of Food Science, Department of Nutrition, Food and Exercise Sciences, Purdue University, Florida State University, West Lafayette, IN 47907-1160, USA Tallahassee, FL 32306-1493, USA Robert L. Bradley, Jr. Baraem Ismail Formerly, Department of Food Science, Department of Food Science and Nutrition, University of Wisconsin, Madison, WI 53706, USA University of Minnesota, St. Paul, MN 55108-6099, USA Charles E. Carpenter W.O. Landen, Jr. Department of Nutrition and Food Sciences, Department of Food Science and Technology, Utah State University, Logan, UT 84322-8700, USA The University of Georgia, Athens, GA 30602-7610, USA Sam K.C. Chang Department of Cereal and Food Sciences, Maurice R. Marshall North Dakota State University, Department of Food Science and Human Nutrition, Fargo, ND 58105, USA University of Florida, Gainesville, FL 32611-0370, USA Christopher R. Daubert Lloyd E. Metzger Department of Food, Bioprocessing Department of Dairy Science, and Nutritional Sciences, University of South Dakota, North Carolina State University, Brookings, SD 57007, USA Raleigh, NC 27695-7624, USA Dennis D. Miller Hulya Dogan Department of Food Science, Cornell University, Department of Grain Science and Industry, Ithaca, NY 14853-7201, USA Kansas State University, Manhattan, KS 66506, USA David B. Min Department of Food Science and Technology, Ronald R. Eitenmiller The Ohio State University, Department of Food Science and Technology, Columbus, OH 43210, USA The University of Georgia, Athens, GA 30602-7610, USA Rubén Morawicki Department of Food Science, Wayne C. Ellefson University of Arkansas, Nutritional Chemistry and Food Safety, Fayetteville, AR 72703, USA Covance Laboritories, Madison, WI 53714, USA Patricia A. Murphy E. Allen Foegeding Department of Food Science Department of Food, Bioprocessing and Human Nutrition, and Nutritional Sciences, Iowa State University, North Carolina State University, Ames, IA 50011, USA Raleigh, NC 27695-7624, USA S. Suzanne Nielsen Yong D. Hang Department of Food Science, Department of Food Science and Technology, Purdue University, Cornell University, Geneva, NY 14456, USA West Lafayette, IN 47907-1160, USA vii viii Contributing Authors Sean F. O’Keefe George D. Sadler Department of Food Science and Technology, PROVE IT LLC Virginia Tech, Blacksburg, VA 24061, USA 204 Deerborne ct. Geneva, IL 60134, USA John R. Pedersen Formerly, Department of Grain Science and Industry, Shelly J. Schmidt Kansas State University, Department of Food Science and Human Nutrition, Manhattan, KS 66506-2201, USA University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA Ronald B. Pegg Department of Food Science and Technology, The University of Georgia, Senay Simsek Athens, GA 30602-7610, USA Department of Plant Sciences, North Dakota State University, Michael H. Penner Fargo, ND 58108-6050, USA Department of Food Science and Technology, Oregon State University, Daniel E. Smith Corvallis, OR 97331-6602, USA Department of Food Science and Technology, Oregon State University, Devin G. Peterson Corvallis, OR 97331-6602, USA Department of Food Science and Nutrition, University of Minnesota, Denise M. Smith St. Paul, MN 55108-6099, USA Department of Food Science and Technology, Oscar A. Pike The Ohio State University, Department of Nutrition, Dietetics, Columbus, OH 43210, USA and Food Science, Brigham Young University, Provo, UT 84602, USA J. Scott Smith Food Science Institute, Kansas State University, Joseph R. Powers Manhattan, KS 66506-1600, USA School of Food Science, Washington State University, Bhadrirju Subramanyam Pullman, WA 99164-6376, USA Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506, USA Michael C. Qian Department of Food Science and Technology, Rohan A. Thakur Oregon State University, Taylor Technology, Princeton, NJ 08540, USA Corvallis, OR 97331-6602, USA Gary A. Reineccius Leonard C. Thomas Department of Food Science and Nutrition, DSC Solutions LLC, Smyrna, DE 19977, USA University of Minnesota, St. Paul, MN 55108-6099, USA Robert E. Ward Department of Nutrition and Food Sciences, Bradley L. Reuhs Utah State University, Department of Food Science, Logan, UT 84322-8700, USA Purdue University, West Lafayette, IN 47907-2009, USA Randy L. Wehling Mary Ann Rounds (deceased) Department of Food Science and Technology, Formerly, Department of Physics, Purdue University, University of Nebraska, West Lafayette, IN 47907, USA Lincoln, NE 68583-0919, USA Michael A. Rutzke Ronald E. Wrolstad Department of Food Science, Department of Food Science and Technology, Cornell University, Oregon State University, Ithaca, NY 14853-7201, USA Corvallis, OR 97331-6602, USA Preface and Acknowledgments The intent of this book is the same as that described in italics type, to help students focus their studies. in the Preface to the first three editions – a text pri- As done for the third edition, the chapters are orga- marily for undergraduate students majoring in food nized into the following sections: I. Introduction, II. science, currently studying the analysis of foods. How- Compositional Analysis of Foods, III. Chemical Prop- ever, comments from users of the first three editions erties and Characteristics of Foods, IV. Spectroscopy, have convinced me that the book is also a valuable text V. Chromatography, and VI. Physical Properties of for persons in the food industry who either do food Foods. Instructors are encouraged to cover the top- analysis or interact with analysts. ics from this text in whatever order is most suitable The big focus of this edition was to do a general for their course. Also, instructors are invited to con- update, adding many new methods and topics and tact me for additional teaching materials related to this deleting outdated/unused methods. The following text book. summarizes changes from the third edition: (1) general Starting with the third edition, the new compe- updates, including addition and deletion of meth- tency requirements established by the Institute of Food ods, (2) combined two chapters to create one chapter Technologists were considered. Those requirements focused on food contaminants, residues, and chemi- relevant to food analysis are as follows: (1) under- cal constituents of concern, (3) some chapters rewrit- standing the principles behind analytical techniques ten by new authors (e.g., Immunoassays, Extraneous associated with food, (2) being able to select the Matter Analysis, Color Analysis, Thermal Analysis), appropriate analytical technique when presented with (4) reorganized some chapters (e.g., Atomic Absorp- a practical problem, and (3) demonstrating practical tion and Atomic Emission Spectroscopy; Basic Chro- proficiency in food analysis laboratory. This textbook matography), (5) added chapter on nuclear magnetic should enable instructors to meet the requirements resonance, (6) added calculations for all practice prob- and develop learning objectives relevant to the first lems, and (7) added table to some chapters to summa- two of these requirements. The laboratory manual, rize methods (e.g., Vitamin Analysis, HPLC), and (8) now in its second edition, should be a useful resource newly drawn figures and photographs. to help students meet the third requirement. Regrettably, in an effort to keep the book at a man- I am grateful to all chapter authors for agree- ageable size and cost, especially for students, some ing to be a part of this project. Many authors have suggestions by users to add chapters could not be drawn on their experience of teaching students and/or accommodated. For specialized topics (e.g., phyto- experience with these analyses to give chapters the chemicals) that utilize the methods included in this appropriate content, relevance, and ease of use. I wish text book, readers are referred to detailed books on to thank the authors of articles and books, and well those topics. as the publishers and industrial companies, for their As stated for the first three editions, the chapters permission to reproduce materials used here. Special in this textbook are not intended as detailed refer- thanks are extended to the following persons: Baraem ences, but as general introductions to the topics and (Pam) Ismail and Brad Reuhs for valuable discussions the techniques. Course instructors may wish to pro- about the content of the book and assistance with edit- vide more details on a particular topic to students. ing; Jonathan DeVries for input that helped determine The chapters focus on principles and applications content; Brooke Sadler for her graphic art work in of techniques. Procedures given are meant to help draw/redrawing many figures; Gwen Shoemaker for explain the principles and give some examples, but keeping track of all the figures and help on equations; are not meant to be presented in the detail ade- and Kirsti Nielsen (my daughter) for word processing quate to actually conduct a specific analysis. As in assistance. the first three editions, all chapters have summaries and study questions, and key words or phrases are S. Suzanne Nielsen ix List of Abbreviations AACC American Association of Cereal CI Chemical ionization Chemists CI Confidence interval AAS Atomic absorption spectroscopy CID Charge injection device ADI Acceptable daily intake CID Collision-induced dissociation AE-HPLC Anion exchange high performance CID Commercial Item Description liquid chromatography CIE Commission Internationale AES Atomic emission spectroscopy d’Eclairage AMS Accelerator mass spectrometer CLA Conjugated linoleic acid AMS Agricultural Marketing Service CLND Chemiluminescent nitrogen detector AOAC Association of Official Analytical COA Certificate of analysis Chemists COD Chemical oxygen demand AOCS American Oil Chemists’ Society C-PER Protein efficiency ratio calculation AOM Active oxygen method method APCI Atmospheric pressure chemical CPG Compliance policy guidance ionization CP-MAS Cross polarization magic angle APE Atmosphere-pressure ionization spinning APHA American Public Health Association CQC 2,6-Dichloroquinonechloroimide APPI Atmospheric pressure CRC Collision reaction cells photo-ionization CSLM Confocal scanning laser microscopy ASE Accelerated solvent extraction CT Computed technology ASTM American Society for Testing CT Computed tomography Materials CV Coefficient of variation ATCC American Type Culture Collection CVM Center for Veterinary Medicine ATF Bureau of Alcohol, Tobacco, Firearms DAL Defect action level and Explosives DDT Dichlorodiphenyltrichloroethane ATP Adenosine-5 -triphosphate DE Degree of esterification ATR Attenuated total reflectance dE∗ Total color difference aw Water activity DF Dilution factor B0 External magnetic field DFE Dietary folate equivalent BAW Base and acid washed DHHS Department of Health and Human BCA Bicinchoninic acid Services BCR Community Bureau of Reference DMA Dynamic mechanical analysis Bé Baumé modulus DMD D -Malate dehydrogenase BHA Butylated hydroxyanisole DMSO Dimethyl sulfoxide BHT Butylated hydroxytoluene DNA Deoxyribronucleic acid BOD Biochemical oxygen demand DNFB 1-Fluoro-2,4-dinitrobenzene BPA Bisphenol A dNTPs Deoxynucleoside triphosphates BSA Bovine serum albumin DON Deoxynivalenol BSDA Bacillus stearothermophilis disk assay DRI Dietary references intake Bt Bacillus thuringiensis DRIFTS Diffuse relectrance Fourier-transform CAST Calf antibiotic and sulfa test spectroscopy CCD Charge-coupled device DRV Daily Reference Value CDC Centers for Disease Control DSC Differential scanning calorimetry CFR Code of Federal Regulations DSHEA Dietary Supplement Health and CFSAN Center for Food Safety and Applied Education Act Nutrition DSPE Dispersive solid-phase extraction cGMP Current Good Manufacturing DTGS Deuterated triglycine sulfate Practices DV Daily value xi xii List of Abbreviations DVB Divinylbenzene GATT General Agreement on Tariffs dwb Dry weight basis and Trade Ea Activation energy GC Gas chromatography EAAI Essential amino acid index GC-AED Gas chromatography – atomic EBT Eriochrome black T emission detector ECD Electron capture detector GC-FTIR Gas chromatography – Fourier EDL Electrode-less discharge lamp transform infrared EDS Energy dispersive spectroscopy GC-MS Gas chromatography – mass EDTA Ethylenediaminetetraacetic acid spectrometry EEC European Economic Community GFC Gel-filtration chromatography EFSA European Food Safety Authority GIPSA Grain Inspection, Packers and EI Electron impact Stockyard Administration EIE Easily ionized elements GLC Gas–liquid chromatography ELCD Electrolytic conductivity detector GMA Grocery Manufacturers of America ELISA Enzyme linked immunosorbent assay GMO Genetically modified organism EPA Environmental Protection Agency GMP Good Manufacturing Practices (also EPSPS 5-Enolpyruvyl-shikimate-3-phsophate Current Good Manufacturing Practice synthase in Manufacturing, Packing, or Eq Equivalents Holding Human Food) ERH Equilibrium relative humidity GOPOD Glucose oxidase/peroxidase ESI Electrospray interface GPC Gel-permeation chromatography ESI Electrospray ionization GRAS Generally recognized as safe ETO Ethylene oxide HACCP Hazard Analysis Critical Control EU European Union Point Fab Fragment antigen binding HCL Hollow cathode lamp FAME Fatty acid methyl esters HETP Height equivalent to a theoretical FAO/WHO Food and Agricultural plate Organization/World Health HFS High fructose syrup Organization HILIC Hydrophilic interaction liquid FAS Ferrous ammonium sulfate chromatography FBs Fumonisins HK Hexokinase Fc Fragment crystallizable H-MAS High-resolution magic angle spinning FCC Food Chemicals Codex HMDS Hexamethyldisilazane FDA Food and Drug Administration HPLC High performance liquid FDAMA Foods and Drug Administration chromatography Modernization Act HPTLC High performance thin-layer FD&C Food, Drug and Cosmetic chromatography FDNB 1-Fluoro-2,4-dinitrobenzene HRGC High resolution gas chromatography FFA Free fatty acid HS Headspace FID Flame ionization detector HVP Hydrolyzed vegetable protein FID Free induction decay IC Ion chromatography FIFRA Federal Insecticide, Fungicide, and IC50 Median inhibition concentration Rodenticide Act ICP Inductively coupled plasma FNB/NAS Food and Nutrition Board of the ICP-AES Inductively coupled plasma – atomic National Academy of Sciences emission spectroscopy FOS Fructooligosaccharide ICP-MS Inductively coupled plasma – mass FPD Flame photometric detector spectrometer FPIA Fluorescence polarization ID Inner diameter immunoassay IDK Insect damaged kernels FSIS Food Safety and Inspection Service Ig Immunoglobulin FT Fourier transform IgE Immunoglobulin E FTC Federal Trade Commission IgG Immunoglobulin G FT-ICR Fourier transform – ion cyclotrons IMS Interstate Milk Shippers FTIR Fourier transform infrared InGaAs Indium–gallium–arsenide G6PDH Glucose-6-phosphate dehydrogenase IR Infrared List of Abbreviations xiii IRMM Institute for Reference Materials and NAD Nicotinamide-adenine dinucleotide Measurements NADP Nicotinamide-adenine dinucleotide ISA Ionic strength adjustor phosphate ISE Ion-selective electrode NADPH Reduced NADP ISO International Organization for NCM N-methyl carbamate Standardization NCWM National Conference on Weights and ITD Ion-trap detector Measures IT-MS Ion traps mass spectrometry NIR Near-infrared IU International Units NIRS Near-infrared spectroscopy IUPAC International Union of Pure and NIST National Institute of Standards and Applied Chemistry Technology JECFA Joint FAO/WHO Expert Committee NLEA Nutrition Labeling and Education Act on Food Additives NMFS National Marine Fisheries Service kcal Kilocalorie NMR Nuclear magnetic resonance KDa Kilodalton NOAA National Oceanic and Atmospheric KFR Karl Fischer reagent Administration KFReq Karl Fischer reagent water NOAEL No observed adverse effect level equivalence NPD Nitrogen phosphorus detector or KHP Potassium acid phthalate thermionic detector LALLS Low-angle laser light scattering NSSP National Shellfish Sanitation Program LC Liquid chromatography NVOC Non-volatile organic compounds LC-MS Liquid chromatography – mass OC Organochlorine spectroscopy OD Outer diameter LFS Lateral flow strip ODS Octadecylsilyl LIMS Laboratory information management OES Optical emission spectroscopy system OMA Official Methods of Analysis LOD Limit of detection OP Organophosphate/organophosphorus LOQ Limit of quantitation OPA O-phthalaldehyde LTM Low thermal mass OSI Oil stability index LTP Low-temperature plasma probe OT Orbitrap 3-MCPD 3-Monochloropropane 1,2-diol OTA Ochratoxin A MALDI-TOF Matrix-assisted laser desorption PAD Pulsed-amperometric detector time-of-flight PAGE Polyacrylamide gel electrophoresis MALLS Multi-angle laser light scattering PAM I Pesticide Analytical Manual, Volume I MAS Magic angle spinning PAM II Pesticide Analytical Manual, MASE Microwave-assisted solvent extraction Volume II MCL Maximum contaminant level Pc Critical pressure MCT Mercury:cadmium:telluride PCBs Polychlorinated biphenyls MDGC Multidimensional gas PCR Polymerase chain reaction chromatography PCR Principal components regression MDL Method detection limit PDCAAS Protein digestibility – corrected amino TM MDSC Modulated differential scanning acid score TM PDMS Polydimethylsiloxane calorimeter mEq Milliequivalents PEEK Polyether ether ketone MES-TRIS 2-(N-morpholino)ethanesulfonic acid- PER Protein efficiency ratio tris(hydroxymethyl)aminomethane PFPD Pulsed flame photometric detector MLR Multiple linear regression pI Isoelectric point MRI Magnetic resonance imaging PID Photoionization detector MRL Maximum residue level PLE Pressurized liquid extraction MRM Multiresidue method PLOT Porous-layer open tabular MS Mass spectrometry (or spectrometer) PLS Partial least squares MS/MS Tandem MS PMO Pasteurized Milk Ordinance Msn Multiple stages of mass spectrometry PMT Photomultiplier tube MW Molecular weight ppb Parts per billion m/z Mass-to-charge ratio PPD Purchase Product Description xiv List of Abbreviations ppm Parts per million SRM Single residue method ppt Parts per trillion SSD Solid state detector PUFA Polyunsaturated fatty acids STOP Swab test on premises PVPP Polyvinylpolypyrrolidone SVOC Semi-volatile organic compounds qMS Quadruple mass spectrometry TBA Thiobarbituric acid QqQ Triple quadrupole TBARS TBA reactive substances Q-trap Quadruple-ion trap TCD Thermal conductivity detector QuEChERS Quick, Easy, Cheap, Effective, Rugged TDA Total daily intake and Safe TDF Total dietary fiber RAC Raw agricultural commodity T-DNA Transfer of DNA RAE Retinol activity equivalents TEM Transmission electron microscopies RASFF Rapid Alert System for Food and Feed TEMED Tetramethylethylenediamine RDA Recommended Daily Allowance Tg Glass transition temperature RDI Reference Daily Intake TGA Thermogravimetric analysis RE Retinol equivalent Ti Tumor-inducing RF Radiofrequency TIC Total ion current Rf Relative mobility TLC Thin-layer chromatography RF Response factor TMA Thermomechanical analysis RI Refractive index TMCS Trimethylchlorosilane RIA Radioimmunoassay TMS Trimethylsilyl ROSA Rapid One Step Assay TOF Time-of-flight RPAR Rebuttable Presumption Against TOF-MS Time-of-flight mass spectrometry Registration TPA Texture profile analysis RVA RapidViscoAnalyser TS Total solids SASO Saudi Arabian Standards TSQ Triple stage quadruple Organization TSS Total soluble solids SBSE Stir bar sorptive extraction TSUSA Tariff Schedules of the United States SD Standard deviation of America SDS Sodium dodecyl sulfate TWI Total weekly intake SDS-PAGE Sodium dodecyl sulfate – UHPC Ultra-high pressure chromatography polyacrylamide gel electrophoresis UHPLC Ultra-high performance liquid SEC Size-exclusion chromatography chromatography SEM Scanning electron microscopy US United States SFC Solid fat content USA United States of America SFC Supercritical-fluid chromatography US RDA United States Recommended Dietary SFC-MS Supercritical-fluid chromatography Allowance mass spectrometry USCS United States Customs Service SFE Supercritical fluid extraction USDA United States Department of SFE-GC Supercritical fluid extraction – gas Agriculture chromatography USDC United States Department of SFI Solid fat index Commerce SI International Scientific USP United States Pharmacopeia SKCS Single kernel characteristics system UV Ultraviolet SMEDP Standard Methods for the UV–Vis Ultraviolet–visible Examination of Dairy Products Vis Visible SO Sulfite oxidase VOC Volatile organic compounds SPDE Solid-phase dynamic extraction wt Weight SPE Solid-phase extraction wwb Wet weight basis SPME Solid-phase microextraction XMT X-ray microtomography SRF Sample response factor ZEA Zearalenone  I part General Information  1 chapter Introduction to Food Analysis S. Suzanne Nielsen Department of Food Science, Purdue University, West Lafayette, IN 47907-2009, USA [email protected] 1.1 Introduction 5 1.5.2 Objective of the Assay 7 1.2 Trends and Demands 5 1.5.3 Consideration of Food Composition 1.2.1 Consumers 5 and Characteristics 8 1.2.2 Food Industry 5 1.5.4 Validity of the Method 9 1.2.3 Government Regulations and International 1.6 Official Methods 10 Standards and Policies 6 1.6.1 AOAC International 10 1.3 Types of Samples Analyzed 6 1.6.2 Other Endorsed Methods 11 1.4 Steps in Analysis 6 1.7 Summary 12 1.4.1 Select and Prepare Sample 6 1.8 Study Questions 12 1.4.2 Perform the Assay 7 1.9 Ackowledgments 13 1.4.3 Calculate and Interpret the Results 7 1.10 References 13 1.5 Choice and Validity of Method 7 1.11 Relevant Internet Addresses 13 1.5.1 Characteristics of the Method 7 S.S. Nielsen, Food Analysis, Food Science Texts Series, DOI 10.1007/978-1-4419-1478-1_1, 3 c Springer Science+Business Media, LLC 2010 Chapter 1 Introduction to Food Analysis 5 1.1 INTRODUCTION here but covered in more detail in Chap. 2, and nutri- tion labeling regulations in the USA are covered in Investigations in food science and technology, whether Chap. 3. Internet addresses for many of the organiza- by the food industry, governmental agencies, or tions and government agencies discussed are given at universities, often require determination of food com- the end of this chapter. position and characteristics. Trends and demands of consumers, the food industry, and national and inter- national regulations challenge food scientists as they 1.2 TRENDS AND DEMANDS work to monitor food composition and to ensure the quality and safety of the food supply. All food prod- 1.2.1 Consumers ucts require analysis as part of a quality management Consumers have many choices regarding their food program throughout the development process (includ- supply, so they can be very selective about the prod- ing raw ingredients), through production, and after a ucts they purchase. They demand a wide variety of product is in the market. In addition, analysis is done products that are of high quality, nutritious, and offer of problem samples and competitor products. The a good value. Also, consumers are concerned about characteristics of foods (i.e., chemical composition, the safety of foods, which has increased the testing physical properties, sensory properties) are used to of foods for allergens, pesticide residues, and prod- answer specific questions for regulatory purposes and ucts from genetic modification of food materials. Many typical quality control. The nature of the sample and consumers are interested in the relationship between the specific reason for the analysis commonly dictate diet and health, so they utilize nutrient content and the choice of analytical methods. Speed, precision, health claim information from food labels to make pur- accuracy, and ruggedness often are key factors in this chase choices. These factors create a challenge for the choice. Validation of the method for the specific food food industry and for its employees. For example, the matrix being analyzed is necessary to ensure useful- demand for foods with lower fat content has chal- ness of the method. Making an appropriate choice lenged food scientists to develop food products that of the analytical technique for a specific application contain fat content claims (e.g., free, low, reduced) and requires a good knowledge of the various techniques certain health claims (e.g., the link between dietary fat (Fig. 1-1). For example, your choice of method to and cancer; dietary saturated fat and cholesterol and determine the salt content of potato chips would be risk of coronary heart disease). Analytical methods different if it is for nutrition labeling than for quality to determine and characterize fat content provide the control. The success of any analytical method relies data necessary to justify these statements and claims. on the proper selection and preparation of the food Use of fat substitutes in product formulations makes sample, carefully performing the analysis, and doing possible many of the lower fat foods, but these fat the appropriate calculations and interpretation of the substitutes can create challenges in the accurate mea- data. Methods of analysis developed and endorsed surement of fat content (1). Likewise, there has been by several nonprofit scientific organizations allow for growing interest in functional foods that may pro- standardized comparisons of results between differ- vide health benefits beyond basic nutrition. However, ent laboratories and for evaluation of less standard such foods present some unique challenges regard- procedures. Such official methods are critical in the ing analytical techniques and in some cases questions analysis of foods, to ensure that they meet the legal of how these components affect the measurement of requirements established by governmental agencies. other nutrients in the food (2). Government regulations and international standards most relevant to the analysis of foods are mentioned 1.2.2 Food Industry To compete in the marketplace, food companies must produce foods that meet the demands of consumers Purpose of Characteristics Compound/Characteristic as described previously. Management of product qual- Analysis of Methods of Interest ity by the food industry is of increasing importance, beginning with the raw ingredients and extending to Applications: the final product eaten by the consumer. Analytical Selecting specific method to methods must be applied across the entire food sup- analyze specific ply chain to achieve the desired final product quality. component/characteristic in specific food Downsizing in response to increasing competition in the food industry often has pushed the responsibil- Method selection in food analysis. ity for ingredient quality to the suppliers. Companies 1-1 increasingly rely on others to supply high-quality and figure 6 Part I General Information safe raw ingredients and packaging materials. Many standards of international organizations. Food sci- companies have select suppliers, on whom they rely entists must be aware of these regulations, guide- to perform the analytical tests to ensure compliance lines, and policies related to food safety and quality with detailed specifications for ingredients/raw mate- and must know the implications for food analysis. rials. These specifications, and the associated tests, Government regulations and guidelines in the USA target various chemical, physical, and microbiologi- relevant to food analysis include nutrition labeling cal properties. Results of these analytical tests related regulations (Chap. 3), mandatory and voluntary stan- to the predetermined specifications are delivered as dards (Chap. 2), Good Manufacturing Practice (GMP) a Certificate of Analysis (COA) with the ingredi- regulations (now called Current Good Manufactur- ent/raw material. Companies must have in place a ing Practice in Manufacturing Packing, or Holding means to maintain control of these COAs and react Human Food) (Chap. 2), and Hazard Analysis Criti- to them. With careful control over the quality of raw cal Control Point (HACCP) systems (Chap. 2). The ingredients/materials, less testing is required during HACCP system is highly demanded of food compa- processing and on the final product. nies by auditing firms and customers. The HACCP In some cases, the cost of goods is linked directly concept has been adopted not only by the US Food to the composition as determined by analytical tests. and Drug Administration (FDA) and other federal For example, in the dairy field, butterfat content of agencies in the USA, but also by the Codex Alimen- bulk tank raw milk determines how much money tarius Commission, an international organization that the milk producer is paid for the milk. For flour, has become a major force in world food trade. Codex the protein content can determine the price and food is described in Chap. 2, along with other organiza- application for the flour. These examples point to the tions active in developing international standards and importance for accurate results from analytical testing. safety practices relevant to food analysis that affect Traditional quality control and quality assurance the import and export of raw agricultural commodities concepts are only a portion of a comprehensive qual- and processed food products. ity management system. Food industry employees responsible for quality management work together in teams with other individuals in the company responsi- 1.3 TYPES OF SAMPLES ANALYZED ble for product development, production, engineering, maintenance, purchasing, marketing, and regulatory Chemical analysis of foods is an important part of a and consumer affairs. quality assurance program in food processing, from Analytical information must be obtained, assessed, ingredients and raw materials, through processing, and integrated with other relevant information about to the finished products (3–7). Chemical analysis the food system to address quality-related problems. also is important in formulating and developing new Making appropriate decisions depends on having products, evaluating new processes for making food knowledge of the analytical methods and equipment products, and identifying the source of problems utilized to obtain the data related to the quality charac- with unacceptable products (Table 1-1). For each type teristics. To design experiments in product and process of product to be analyzed, it may be necessary to development, and to assess results, one must know the determine either just one or many components. The operating principles and capabilities of the analytical nature of the sample and the way in which the infor- methods. Upon completion of these experiments, one mation obtained will be used may dictate the specific must critically evaluate the analytical data collected to method of analysis. For example, process control sam- determine whether product reformulation is needed ples are usually analyzed by rapid methods, whereas or what parts of the process need to be modified for nutritive value information for nutrition labeling gen- future tests. The situation is similar in the research lab- erally requires the use of more time-consuming meth- oratory, where knowledge of analytical techniques is ods of analysis endorsed by scientific organizations. necessary to design experiments, and the evaluation of Critical questions, including those listed in Table 1-1, data obtained determines the next set of experiments can be answered by analyzing various types of sam- to be conducted. ples in a food processing system. 1.2.3 Government Regulations 1.4 STEPS IN ANALYSIS and International Standards and Policies 1.4.1 Select and Prepare Sample To market safe, high-quality foods effectively in a national and global marketplace, food compa- In analyzing food samples of the types described pre- nies must pay increasing attention to government viously, all results depend on obtaining a represen- regulations and guidelines and to the policies and tative sample and converting the sample to a form Chapter 1 Introduction to Food Analysis 7 to a specific type of food product. Single chapters 1-1 Types of Samples Analyzed in a Quality in this book address sampling and sample prepara- table Assurance Program for Food Products tion (Chap. 5) and data handling (Chap. 4), while the Sample Type Critical Questions remainder of the book addresses the step of actually performing the assay. The descriptions of the vari- Raw materials Do they meet your specifications? ous specific procedures are meant to be overviews of Do they meet required legal the methods. For guidance in actually performing the specifications? assays, details regarding chemicals, reagents, appa- Are they safe and authentic? Will a processing parameter have to be ratus, and step-by-step instructions are found in the modified because of any change in the books and articles referenced in each chapter. Numer- composition of raw materials? ous chapters in this book, and other recent books Are the quality and composition the same devoted to food analysis (10–14), make the point as for previous deliveries? that for food analysis we increasingly rely on expen- How does the material from a potential new supplier compare to that from the sive equipment, some of which requires considerable current supplier? expertise. Also, it should be noted that numerous Process Did a specific processing step result in a analytical methods utilize automated instrumentation, control product of acceptable composition or including autosamplers and robotics to speed the samples characteristics? analyses. Does a further processing step need to be modified to obtain a final product of acceptable quality? 1.4.3 Calculate and Interpret the Results Finished Does it meet the legal requirements? product What is the nutritive value, so that label To make decisions and take action based on the results information can be developed? Or is obtained from performing the assay that determined the nutritive value as specified on an the composition or characteristics of a food product, existing label? one must make the appropriate calculations to inter- Does it meet product claim requirements pret the data correctly. Data handling, covered in (e.g., “low fat”)? Will it be acceptable to the consumer? Chap. 4, includes important statistical principles. Will it have the appropriate shelf life? If unacceptable and cannot be salvaged, how do you handle it (trash? rework? 1.5 CHOICE AND VALIDITY OF METHOD seconds?) Competitor’s What are its composition and 1.5.1 Characteristics of the Method sample characteristics? How can we use this information to Numerous methods often are available to assay food develop new products? samples for a specific characteristic or component. To Complaint How do the composition and select or modify methods used to determine the chem- sample characteristics of a complaint sample ical composition and characteristics of foods, one must submitted by a customer differ from a be familiar with the principles underlying the pro- sample with no problems? cedures and the critical steps. Certain properties of methods and criteria described in Table 1-2 are useful Adapted and updated from (8, 9). to evaluate the appropriateness of a method in current that can be analyzed. Neither of these is as easy use or a new method being considered. as it sounds! Sampling and sample preparation are covered in detail in Chap. 5. 1.5.2 Objective of the Assay Sampling is the initial point for sample identi- fication. Analytical laboratories must keep track of Selection of a method depends largely on the objec- incoming samples and be able to store the analytical tive of the measurement. For example, methods used data from the analyses. This analytical information for rapid online processing measurements may be often is stored on a laboratory information manage- less accurate than official methods (see Sect. 1.6) used ment system, or LIMS, which is a computer database for nutritional labeling purposes. Methods referred to program. as reference, definitive, official, or primary are most applicable in a well-equipped and staffed analytical lab. The more rapid secondary or field methods may 1.4.2 Perform the Assay be more applicable on the manufacturing floor in a Performing the assay is unique for each component food processing facility. For example, refractive index or characteristic to be analyzed and may be unique may be used as a rapid, secondary method for sugar 8 Part I General Information 1-2 table Criteria for Choice of Food Analysis Methods Characteristic Critical Questions Inherent properties Specificity/selectivity Is the property being measured the same as that claimed to be measured, and is it the only property being measured? Are there interferences? What steps are being taken to ensure a high degree of specificity? Precision What is the precision of the method? Is there within-batch, batch-to-batch, or day-to-day variation? What step in the procedure contributes the greatest variability? Accuracy How does the new method compare in accuracy to the old or a standard method? What is the percent recovery? Applicability of method to laboratory Sample size How much sample is needed? Is it too large or too small to fit your needs? Does it fit your equipment and/or glassware? Can you obtain representative sample?a Reagents Can you properly prepare them? What equipment is needed? Are they stable? For how long and under what conditions? Equipment Is the method very sensitive to slight or moderate changes in the reagents? Do you have the appropriate equipment? Are personnel competent to operate equipment? Cost What is the cost in terms of equipment, reagents, and personnel? Usefulness Time required How fast is it? How fast does it need to be? Reliability How reliable is it from the standpoints of precision and stability? Need Does it meet a need or better meet a need? Personnel Is any change in method worth the trouble of the change? Safety Are special precautions necessary? Procedures Who will prepare the written description of the procedures and reagents? Who will do any required calculations? a In-process samples may not accurately represent finished product; Must understand what variation can and should be present. analysis (see Chaps. 6 and 10), with results correlated lipid, protein, and carbohydrate). In food analysis, it to those of the primary method, high-performance is usually the food matrix that presents the greatest liquid chromatography (HPLC) (see Chaps. 10 and challenge to the analyst (15). For example, high-fat 28). Moisture content data for a product being devel- or high-sugar foods can cause different types of inter- oped in the pilot plant may be obtained quickly ferences than low-fat or low-sugar foods. Digestion with a moisture balance unit that has been calibrated procedures and extraction steps necessary for accurate using a more time-consuming hot air oven method analytical results can be very dependent on the food (see Chap. 6). Many companies commonly use unoffi- matrix. The complexity of various food systems often cial, rapid methods, but validate them against official requires having not just one technique available for a methods. specific food component, but multiple techniques and procedures, as well as the knowledge about which to apply to a specific food matrix. A task force of AOAC International, formerly 1.5.3 Consideration of Food Composition known as the Association of Official Analytical and Characteristics Chemists (AOAC), suggested a “triangle scheme” for Proximate analysis of foods refers to determining the dividing foods into matrix categories (16–20) (Fig. 1-2). major components of moisture (Chap. 6), ash (total The apexes of the triangle contain food groups that minerals) (Chap. 7), lipids (Chap. 8), protein (Chap. 9), were either 100% fat, 100% protein, or 100% car- and carbohydrates (Chap. 10). The performance of bohydrate. Foods were rated as “high,” “low,” or many analytical methods is affected by the food “medium” based on levels of fat, carbohydrate, and matrix (i.e., its major chemical components, especially proteins, which are the three nutrients expected to Chapter 1 Introduction to Food Analysis 9 Schematic layout of food matrixes based on protein, fat, and carbohydrate content, excluding moisture and ash. 1-2 [Reprinted with permission from (20), Inside Laboratory Management, September 1997, p. 33. Copyright 1997, by figure AOAC International.] have the strongest effect on analytical method per- analysis, how representative the samples were of the formance. This created nine possible combinations of whole, and the number of samples analyzed (Chap. 5). high, medium, and low levels of fat, carbohydrate, and One must ask whether details of the analytical proce- protein. Complex foods were positioned spatially in dure were followed adequately, such that the results the triangle according to their content of fat, carbo- are accurate, repeatable, and comparable to data col- hydrate, and protein, on a normalized basis (i.e., fat, lected previously. For data to be valid, equipment to carbohydrate, and protein normalized to total 100%). conduct the analysis must be standardized and appro- General analytical methods ideally would be geared to priately used, and the performance limitations of the handle each of the nine combinations, replacing more equipment must be recognized. numerous matrix-dependent methods developed for A major consideration for determining method specific foods. For example, using matrix-dependent validity is the analysis of materials used as controls, methods, one method might be applied to potato often referred to as standard reference materials or chips and chocolates, both of which are low-protein, check samples (21). Analyzing check samples con- medium-fat, medium-carbohydrate foods, but another currently with test samples is an important part of might be required for a high-protein, low-fat, high- quality control (22). Standard reference materials can carbohydrate food such as nonfat dry milk (17). In be obtained in the USA from the National Institute contrast, a robust general method could be used for of Standards and Technology (NIST) and from US all of the food types. The AACC International, for- Pharmacopeia, in Canada from the Center for Land merly known as the American Association of Cereal and Biological Resource Research, in Europe from Chemists (AACC), has approved a method studied the Institute for Reference Materials and Measure- using this approach (18). ments (IRMM), and in Belgium from the Commu- nity Bureau of Reference (BCR). Besides government- related groups, numerous organizations offer check 1.5.4 Validity of the Method sample services that provide test samples to evaluate Numerous factors affect the usefulness and valid- the reliability of a method (21). For example, AACC ity of the data obtained using a specific analytical International has a check sample service in which a method. One must consider certain characteristics of subscribing laboratory receives specifically prepared any method, such as specificity, precision, accuracy, test samples from AACC International. The subscrib- and sensitivity (see Table 1-2 and Chap. 4). However, ing laboratory performs the specified analyses on the one also must consider how the variability of data samples and returns the results to AACC Interna- from the method for a specific characteristic com- tional. The AACC International then provides a statis- pares to differences detectable and acceptable to a tical evaluation of the analytical results and compares consumer, and the variability of the specific charac- the subscribing laboratory’s data with those of other teristic inherent in processing of the food. One must laboratories to inform the subscribing laboratory of consider the nature of the samples collected for the its degree of accuracy. The AACC International offers 10 Part I General Information check samples such as flours, semolina, and other This volunteer organization functions as cereal-based samples, for analyses such as moisture, follows: ash, protein, vitamins, minerals, sugars, sodium, total dietary fiber, soluble and insoluble dietary fiber, and 1. Methods of analysis from published literature β-glucan. Samples also are available for testing phys- are selected or new methods are developed by ical properties and for microbiological and sanitation AOAC International volunteers. analyses. 2. Methods are collaboratively tested using multi- The American Oil Chemists’ Society (AOCS) laboratory studies in volunteers’ laboratories. has a reference sample program for oilseeds, oilseed 3. Methods are given a multilevel peer review by meals, marine oils, aflatoxin, cholesterol, trace met- expert scientists, and if found acceptable, they als, specialty oils suitable for determination of trans are adopted as official methods of analysis. fatty acids, and formulations for nutritional labeling. 4. Adopted methods are published in the Official Laboratories from many countries participate in the Methods of Analysis, which covers a wide vari- program to check the accuracy of their work, their ety of assays related to foods, drugs, cosmet- reagents, and their laboratory apparatus against the ics, agriculture, forensic science, and products statistical norm derived from the group data. affecting public health and welfare. Standard reference materials are important tools 5. AOAC International publishes manuals, meth- to ensure reliable data. However, such materials need ods compilations in specific areas of analysis, not necessarily be obtained from outside organiza- monographs, and the monthly magazine Inside tions. Control samples internal to the laboratory can Laboratory Management. be prepared by carefully selecting an appropriate type 6. AOAC International conducts training courses of sample, gathering a large quantity of the material, of interest to analytical scientists and other lab- mixing and preparing to ensure homogeneity, pack- oratory personnel. aging the sample in small quantities, storing the sam- Methods validated and adopted by AOAC Inter- ples appropriately, and routinely analyzing the control national and the data supporting the method valida- sample when test samples are analyzed. Whatever the tion are published in the Journal of AOAC International. standard reference materials used, these should match Such methods must be successfully validated in a for- closely the matrix of the samples to be analyzed by mal interlaboratory collaborative study before being a specific method. AOAC International has begun a accepted as an official first action method by AOAC peer-review program of matching reference materials International. Details of the validation program (e.g., with respective official methods of analysis. number of laboratories involved, samples per level of analyte, controls, control samples, and the review process) are given in the front matter of the AOAC 1.6 OFFICIAL METHODS International’s Official Methods of Analysis. First action methods are subject to scrutiny and general testing The choice of method for a specific characteristic or by other scientists and analysts for some time period component of a food sample is often made easier by before final action adoption. Adopted first action and the availability of official methods. Several nonprofit final action methods for many years were compiled in scientific organizations have compiled and published books published and updated every 4–5 years as the these methods of analysis for food products, which Official Methods of Analysis (23) of AOAC International. have been carefully developed and standardized. They In 2007, AOAC International created an online version allow for comparability of results between different of the book as a “continuous edition,” with new and laboratories that follow the same procedure and for revised methods posted as soon as they are approved. evaluating results obtained using new or more rapid The Official Methods of Analysis of AOAC International procedures. includes methods appropriate for a wide variety of products and other materials (Table 1-3). These meth- 1.6.1 AOAC International ods often are specified by the FDA with regard to legal requirements for food products. They are gener- AOAC International is an organization begun in 1884 ally the methods followed by the FDA and the Food to serve the analytical methods needs of government Safety and Inspection Service (FSIS) of the United regulatory and research agencies. The goal of AOAC States Department of Agriculture (USDA) to check International is to provide methods that will be fit for the nutritional labeling information on foods and to their intended purpose (i.e., will perform with the nec- check foods for the presence or absence of undesirable essary accuracy and precision under usual laboratory residues or residue levels. conditions). Chapter 1 Introduction to Food Analysis 11 1-3 Table of Contents of 2007 Official Methods 1-4 Table of Contents of 2010 Approved table of Analysis of AOAC International (23) table Methods of AACC International (24) Chapter Title Chapter Title 1 Agriculture liming materials 2 Acidity 2 Fertilizers 4 Acids 3 Plants 6 Admixture of flours 4 Animal feed 7 Amino acids 5 Drugs in feeds 8 Total ash 6 Disinfectants 10 Baking quality 7 Pesticide formulations 11 Biotechnology 8 Hazardous substances 12 Carbon dioxide 9 Metals and other elements at trace levels in foods 14 Color and pigments 10 Pesticide and industrial chemical residues 20 Ingredients 11 Waters; and salt 22 Enzymes 12 Microchemical methods 26 Experimental milling 13 Radioactivity 28 Extraneous matter 14 Veterinary analytical toxicology 30 Crude fat 15 Cosmetics 32 Fiber 16 Extraneous materials: isolation 33 Sensory analysis 17 Microbiological methods 38 Gluten 18 Drugs: Part I 39 Infrared analysis 19 Drugs: Part II 40 Inorganic constituents 20 Drugs: Part III 42 Microorganisms 21 Drugs: Part IV 44 Moisture 22 Drugs: Part V 45 Mycotoxins 23 Drugs and feed additives in animal tissues 46 Nitrogen 24 Forensic sciences 48 Oxidizing, bleaching, and maturing agents 25 Baking powders and baking chemicals 54 Physical dough tests 26 Distilled liquors 55 Physical tests 27 Malt beverages and brewing materials 56 Physicochemical tests 28 Wines 58 Special properties of fats, oils, and shortenings 29 Nonalcoholic beverages and concentrates 61 Rice 30 Coffee and tea 62 Preparation of sample 31 Cacao bean and its products 64 Sampling 32 Cereal foods 66 Semolina, pasta, and noodle quality 33 Dairy products 68 Solutions 34 Eggs and egg products 74 Staleness/texture 35 Fish and other marine products 76 Starch 36 Flavors 78 Statistical principles 37 Fruits and fruit products 80 Sugars 38 Gelatin, dessert preparations, and mixes 82 Tables 39 Meat and meat products 86 Vitamins 40 Nuts and nut products 89 Yeast 41 Oils and fats 42 Vegetable products, processed 43 Spices and other condiments 44 Sugars and sugar products 45 Vitamins and other nutrients 46 Color additives 47 Food additives: Direct 48 Food additives: Indirect staleness/texture). The AACC International process 49 Natural toxins of adopting the Approved Methods of Analysis (24) is 50 Infant formulas, baby foods, and enteral products 51 Dietary supplements consistent with the process used by the AOAC Inter- national and AOCS. Approved methods of the AACC International are continuously reviewed, critiqued, and updated (Table 1-4), and are now available online. The AOCS publishes a set of official methods and 1.6.2 Other Endorsed Methods recommended practices, applicable mostly to fat and The AACC International publishes a set of approved oil analysis (e.g., vegetable oils, glycerin, lecithin) laboratory methods, applicable mostly to cereal prod- (25) (Table 1-5). AOCS is a widely used methodology ucts (e.g., baking quality, gluten, physical dough tests, source on the subjects of edible fats and oils, oilseeds 12 Part I General Information Table of Contents of 2009 Official Methods methods for the analysis of certain food additives. 1-5 and Recommended Practices of the Some trade associations publish standard methods for table American Oil Chemists’ Society (25) the analysis of their specific products. Section Title A Vegetable oil source materials B Oilseed by-products 1.7 SUMMARY C Commerical fats and oils D Soap and synthetic detergents Food scientists and technologists determine the chem- E Glycerin ical composition and physical characteristics of foods F Sulfonated and sulfated oils routinely as part of their quality management, product G Soapstocks development, or research activities. For example, the H Specifications for reagents, and solvents and apparatus types of samples analyzed in a quality management J Lecithin program of a food company can include raw materi- M Evaluation and design of test methods als, process control samples, finished products, com- S Official listings petitors’ samples, and consumer complaint samples. T Recommended practices for testing industrial oils Consumer, food industry, and government concern for and derivatives food quality and safety has increased the importance of analyses that determine composition and critical product characteristics. Contents of Chap. 15 on Chemical and To successfully base decisions on results of any 1-6 Physical Methods in Standard Methods analysis, one must correctly conduct all three major table for the Examination of Dairy Products (26) steps in the analysis: (1) select and prepare samples, (2) perform the assay, and (3) calculate and interpret 15.010 Introduction the results. The choice of analysis method is usually 15.020 Acidity tests based on the objective of the analysis, characteris- 15.030 Adulterant tests 15.040 Ash tests tics of the method itself (e.g., specificity, accuracy, 15.050 Chloride tests precision, speed, cost of equipment, and training of 15.060 Contaminant tests personnel), and the food matrix involved. Validation 15.070 Extraneous material tests of the method is important, as is the use of standard 15.080 Fat determination methods reference materials to ensure quality results. Rapid 15.090 Lactose and galactose tests 15.100 Minerals and food additives methods used for quality assessment in a produc- 15.110 Moisture and solids tests tion facility may be less accurate but much faster 15.120 Multicomponent tests than official methods used for nutritional labeling. 15.130 Protein/nitrogen tests Endorsed methods for the chemical analyses of foods 15.140 Rancidity tests have been compiled and published by AOAC Inter- 15.150 Sanitizer tests national, AACC International, AOCS, and certain 15.160 Vitamins A, D2, and D3 in milk products, HPLC method other nonprofit scientific organizations. These meth- 15.170 Functional tests ods allow for comparison of results between different 15.180 Cited references laboratories and for evaluation of new or more rapid procedures. and oilseed proteins, soaps and synthetic detergents, 1.8 STUDY QUESTIONS industrial fats and oils, fatty acids, oleochemicals, glycerin, and lecithin. 1. Identify six reasons you might need to determine certain Standard Methods for the Examination of Dairy Prod- chemical characteristics of a food product as part of a ucts (26), published by the American Public Health quality management program. Association, includes methods for the chemical analy- 2. You are considering the use of a new method to measure Compound X in your food product. List six factors you sis of milk and dairy products (e.g., acidity, fat, lactose, will consider before adopting this new method in your moisture/solids, added water) (Table 1-6). Standard quality assurance laboratory. Methods for the Examination of Water and Wastewater (27) 3. In your work at a food company, you mentioned to a is published jointly by the American Public Health coworker something about the Official Methods of Analy- Association, American Water Works Association, and sis published by AOAC International. The coworker asks the Water Environment Federation. Food Chemicals you what AOAC International does, and what the Official Codex (28), published by US Pharmacopeia, contains Methods of Analysis is. Answer your coworker’s questions. Chapter 1 Introduction to Food Analysis 13 4. For each type of product listed below, identify a publica- 15. Wetzel DLB, Charalambous G (eds) (1998) Instrumental tion in which you can find standard methods of analysis methods in food and beverage analysis. Elsevier Science, appropriate for the product: Amsterdam, The Netherlands (a) Ice cream 16. AOAC International (1993) A food matrix organizational (b) Enriched flour system applied to collaborative studies. Referee 17(7): (c) Wastewater (from food processing plant) 1, 6, 7 (d) Margarine 17. Lovett RA (1997) U.S. food label law pushes fringes of analytical chemistry. Inside Lab Manage 1(4):27–28 18. DeVries JW, Silvera KR (2001) AACC collaborative study of a method for determining vitamins A and E in foods 1.9 ACKOWLEDGMENTS by HPLC (AACC Method 86–06). Cereal Foods World 46(5):211–215 The author thanks the numerous former students, 19. Sharpless KE, Greenberg RR, Schantz MM, Welch MJ, working in quality assurance in the food industry, who Wise SA, Ihnat M (2004) Filling the AOAC triangle with reviewed this chapter and contributed ideas for its food-matrix standard reference materials. Anal Bioanal revision. Chem 378:1161–1167 20. Ellis C, Hite D, van Egmond H (1997) Development of methods to test all food matrixes unrealistic, says OMB. Inside Lab Manage 1(8):33–35 1.10 REFERENCES 21. Latimer GW Jr (1997) Check sample programs keep laboratories in sync. Inside Lab Manage 1(4):18–20 1. Flickinger B (1997) Challenges and solutions in compo- 22. Ambrus A (2008) Quality assurance, Ch. 5. In: Tadeo JL sitional analysis. Food Quality 3(19):21–26 (ed) Analysis of pesticides in food and environmental 2. Spence JT (2006) Challenges related to the composition samples. CRC, New York, p 145 of functional foods. J Food Compost Anal 19 Suppl 1: 23. AOAC International (2007) Official methods of analysis, S4–S6 18th edn., 2005; current through revision 2, 2007 (On- 3. Alli I (2003) Food quality assurance: principles and line). AOAC International, Gaithersburg, MD practices. CRC, Boca Raton, FL 24. AACC International (2010) Approved methods of analy- 4. Vasconcellos JA (2004) Quality assurances for the food sis, 11th edn (online). AACC International, St. Paul, MN industry: a practical approach. CRC, Boca Raton, FL 25. AOCS (2009) Official methods and recommended 5. Multon J-L (1995) Analysis and control methods for practices, 6th edn. American Oil Chemists’ Society, foods and agricultural products, vol 1: quality control Champaign, IL for foods and agricultural products. Wiley, New York 26. Wehr HM, Frank JF (eds) (2004) Standard methods for 6. Linden G, Hurst WJ (1996) Analysis and control meth- the examination of dairy products, 17th edn. American ods for foods and agricultural products, vol 2: analytical Public Health Association, Washington, DC techniques for foods and agricultural products. Wiley, 27. Eaton AD, Clesceri LS, Rice EW, Greenberg AE (eds) New York (2005) Standard methods for the examination of water 7. Multon J-L, Stadleman WJ, Watkins BA (1997) Anal- and wastewater, 21st edn. American Public Health Asso- ysis and control methods for foods and agricultural ciation, Washington, DC products, vol 4: analysis of food constituents. Wiley, 28. U.S. Pharmacopeia (USP) (2008) Food chemicals codex, New York 6th edn. United Book, Baltimore, MD 8. Pearson D (1973) Introduction – some basic principles of quality control, Ch. 1. In: Laboratory techniques in food analysis. Wiley, New York, pp 1–26 9. Pomeranz Y, Meloan CE (1994) Food analysis: theory 1.11 RELEVANT INTERNET ADDRESSES and practice, 3rd edn. Chapman & Hall, New York 10. Jones L (2005) Chemical analysis of food: an introduc- American Association of Cereal Chemists – tion. Campden & Chorleywood Food Research Associa- http://www.aaccnet.org/ tion, Gloucestershire, UK American Oil Chemists’ Society – 11. Tothill IE (2003) Rapid and on-line instrumentation for http://www.aocs.org/ food quality assurance. Woodhead, CRC, Boca Raton, FL American Public Health Association – 12. Nollett LML (2004) Handbook of food analysis, 2nd edn, http://www.apha.org/ vol 1: physical characterization and nutrient analysis, AOAC International – http://www.aoac.org vol 2: residues and other food component analysis. CRC, Code of Federal Regulations – Boca Raton, FL 13. Otles S (2005) Methods of analysis of food components http://www.gpoaccess.gov/cfr/index.html and additives. Woodhead, Cambridge, England Codex Alimentarius Commission – 14. Otles S (2008) Handbook of food analysis instruments. http://www.codexalimentarius.net/web/ CRC, Boca Raton, FL index_en.jsp 14 Part I General Information Food Chemicals Codex – National Institute of Standards and Technology – http://www.usp.org/fcc/ http://www.nist.gov/ Food and Drug Administration – U.S. Department of Agriculture – http://www.fda.gov http://www.usda.gov/wps/portal/usdahome Center for Food Safety & Applied Nutrition – Food Safety and Inspection Service – http://www.cfsan.fda.gov/ http://www.fsis.usda.gov Current Good Manufacturing Practices – HACCP/Pathogen Reduction – http://www.cfsan.fda.gov/ http://www.fsis.usda.gov/Science/ ∼dms/cgmps.html Hazard_Analysis_\&_Pathogen_ Food Labeling and Nutrition – Reduction/index.asp http://vm.cfsan.fda.gov/label.html Hazard Analysis Critical Control Point – http://www.cfsan.fda.gov/~lrd/haccp.html  2 chapter United States Government Regulations and International Standards Related to Food Analysis S. Suzanne Nielsen Department of Food Science, Purdue University, West Lafayette, IN 47907-2009, USA [email protected] 2.1 Introduction 17 2.2.1.1.1 Federal Food, Drug, and 2.2 US Federal Regulations Affecting Food Cosmetic Act of 1938 17 Composition 17 2.2.1.1.2 Amendments and 2.2.1 US Food and Drug Administration 17 Additions to the 1938 2.2.1.1 Legislative History 17 FD&C Act 17 S.S. Nielsen, Food Analysis, Food Science Texts Series, DOI 10.1007/978-1-4419-1478-1_2, 15 c Springer Science+Business Media, LLC 2010 16 Part I General Information 2.2.1.1.3 Other FDA 2.2.7 US Federal Trade Commission 25 Regulations 18 2.2.7.1 Enforcement Authority 25 2.2.1.2 Food Definitions and 2.2.7.2 Food Labels, Food Composition, Standards 18 and Deceptive Advertising 26 2.2.1.3 Inspection and Enforcement 19 2.3 Regulations and Recommendations for Milk 26 2.2.2 US Department of Agriculture 21 2.3.1 FDA Responsibilities 26 2.2.2.1 Standards of Identity 2.3.2 USDA Responsibilities 27 for Meat Products 21 2.3.3 State Responsibilities 27 2.2.2.2 Grade Standards 21 2.4 Regulations and Recommendations for 2.2.2.3 Inspection Programs 22 Shellfish 27 2.2.3 US Department of Commerce 22 2.4.1 State and Federal Shellfish 2.2.3.1 Seafood Inspection Service 22 Sanitation Programs 27 2.2.3.2 Interaction with FDA and EPA 22 2.4.2 Natural and Environmental Toxic 2.2.4 US Bureau of Alcohol, Tobacco, Firearms Substances in Shellfish 28 and Explosives 22 2.5 Voluntary Federal Recommendations Affecting 2.2.4.1 Regulatory Responsibility Food Composition 28