User:Whitapa61/Dr. thomas b. whitaker

Dr.Thomas B. Whitaker, Ph.D.
 * Curriculum Vitae

Agricultural Engineer U.S. Department of Agriculture, Agricultural Research Service Market Quality and Handling Research Unit Professor Biological and Agricultural Engineering Department NC State University, Raleigh, North Carolina Fellow, American Society of Agricultural Engineers Fellow, American Peanut Research and Education Society

Education

B.S. (Agricultural Engineering), NC State University		1962 M.S. (Agricultural Engineering), NC State University		1964 Ph.D. (Agricultural Engineering), Ohio State University	1967

Professional Experience

Agricultural Engineer, U.S. Dept. of Agriculture, Agricultural Research Service, Raleigh, NC, June 1967 to Present

Responsibilities: Develop methods to evaluate the performance of mycotoxin sampling plans for agricultural commodities. Methods include (1) the measurement of variability associated with sampling, sample preparation, and analysis, (2) determination of the distribution among replicated sample test results, and (3) development of statistical models to predict the performance of mycotoxin sampling plans. Assist domestic and international producers, processors, manufacturers, exporters, importers, regulatory agencies, and research institutions to design and evaluate mycotoxin sampling plans for control programs. Methods developed to evaluate the performance of mycotoxin sampling plans have been extended to evaluate the performance of sampling plans used to detect genetically modified seed in grain, TCK spores in wheat, pesticide on seed, protein allergens in food products, and toxic compounds in fruit. Holds the rank of Professor, Biological and Agricultural Engineering Department, NC State University.

Notable accomplishments: Dr. Whitaker’s research career with ARS has spanned 39 years. He has authored or co-authored 112 refereed publications, which include 10 book chapters and government publications, and have made over 100 presentations at national and international scientific meetings and workshops. His research efforts, directed toward the development of methods to evaluate the performance and the design of mycotoxin sampling plans for agricultural commodities, have established Dr. Whitaker as a recognized expert and world leader in his field. Dr. Whitaker’s research program has been recognized by the Food Engineering Division of the American society of Agricultural Engineers (ASAE) as one of the six outstanding research achievements of the 20th Century and he received the Harvey W. Wiley Award from Association of Official Analytical Chemists (AOAC) for achievements in research. Internationally, the incumbent has been invited to participate as a member of (1) US/European Technical Committee sponsored by the American Peanut Council, which led to a USDA/EC Origin Certification Program to test U.S. export peanuts for aflatoxin and certify that they met EC aflatoxin regulations, (2) U.S. delegations associated with two FAO/WHO CODEX Committees, (3) two Expert Consultation sponsored by the FAO/WHO and (4) an USDA/ARS TCK Task Force team to help to open China market for US wheat. The methods developed to evaluate the performance of mycotoxin sampling plans have been accepted and used by USDA, FDA, the US peanut and grain industries, and internationally by FAO/WHO, IAEA, and regulatory agencies and food manufacturers in the various countries such as The Netherlands, EC, and Brazil. Numerous awards from USDA, the peanut industry, and professional societies have recognized Dr. Whitaker’s research accomplishments. As a result of his research programs, other scientists are now aware of the nature of mycotoxin testing errors and other researchers worldwide are duplicating his research methods.

Graduate Research Assistant, Agric. Eng. Dept., Ohio State Univ.		1964-1967

Responsibilities: Developed mathematical models, using moisture diffusion theory, to predict the moisture content at any point in a spherical body. The mathematical model will help establish design requirements for agricultural drying systems on a rational basis. Ph.D. thesis: Theoretical and experimental studies of diffusion in spherical bodies with a variable diffusion coefficient.

Graduate Research Assistant, Biol. and Agric. Eng. Dept., NC State Univ. 1962-1964

Responsibilities: Designed experimental studies and analyzed respiration data that demonstrated that oxygen can’t diffuse into peanut kernels at a sufficient rate to support the high respiration rates that occur during high temperature curing. As a result, respiration changes from aerobic to anaerobic and produces off-flavor compounds in curing peanuts. M.S. thesis: The effect of curing on respiration and off-flavor in peanuts.

Professional Honors

Merit Award, USDA/ARS, 2005 Coyt T. Wilson Distinguished Service Award, American peanut Research and Education Society, 2005

Harvey W. Wiley Award, Association of Official Analytical Chemists, 2003

American Peanut Research and Education Award, American Peanut Council, 2002

Merit Award, USDA/ARS, 2001

Invited by FAO/WHO to be a member of Joint Expert Committee on Food Additive (JECFA) to determine human risks to five mycotoxins in food products, Food and Agriculture Organization, World Health Organization, United Nations, 2000

Secretary of Agriculture Group Honors Award for Excellence, USDA/ARS, 2000

Outstanding Research Achievement of the 20th Century, American Society of Agricultural Engineers, 2000

Merit Award, USDA/ARS, 1999

Invited to be a Guest Editor, Journal of the Association of Official Analytical Chemists, International, 2000

Inducted into Gamma Sigma Delta, NC State University Chapter, 1999

Dow AgroSciences Award for Excellence in Research, American Peanut Research and Education Society, 1998

Appointed to CAST Task Force Team for Mycotoxin Publication, American Society of Agricultural Engineers, 1997

Certificate of Merit for Research Accomplishments, Gamma Sigma Delta, NC State University Chapter, 1997

Elected Fellow, American Peanut Research and Education Society,	1996

Elected Fellow, American Society of Agricultural Engineers, 1995

Appointed Associate Referee for Sampling, Association of Official Analytical Chemists, International, 1995

Invited to FAO/WHO Expert Consultation on Sampling Corn and Peanuts for Aflatoxin, Food and Agriculture Organization, United Nations, 1993

Bailey Award, American Peanut Research and Education Society, 1992

Merit Award, USDA/ARS, 1992

Merit Award, USDA/ARS, 1988

Merit Award, USDA/ARS, 1982

Golden Peanut Research Award, American Peanut Council, 1980

Bailey Award, American Peanut Research and Education Society, 1976

Paper Award, American Society of Agricultural Engineers, 1974

Professional Societies

American Society of Agricultural Engineers (ASAE) Association of Official Analytical Chemists, International (AOAC) American Peanut Research and Education Society (APRES) Council for Agricultural Science and Technology (CAST) Gamma Sigma Delta Sigma Xi American Chemical Society

Refereed Publications Last 5 years (21 of 112)

Whitaker, T.B., Richard, J.R., Giesbrecht, F.G., Slate, A.B., and Ruiz, N. 2003. Estimating deoxynivalenol in shelled corn barge lots by measuring deoxynivalenol in corn screenings. J. Assoc. Off. Analytical Chem., Int., 86:1187-1192.

Whitaker, T. B. 2003. Detecting Mycotoxins in Agricultural Commodities. J. Molecular Biotechnology 23:61-71.

Whitaker, T. B. 2003. Detection of Mycotoxins, IN: Mycotoxins: Risks in Plant, Animal, and Human Systems, CAST Task Force Report Number 139, Council for Agriculture Science and Technology, Ames, Iowa, pp. 199.

Whitaker, T.B., Giesbrecht, F.G., and Slate, A.B. 2003. Market system model to predict the effects of regulatory and processing practices on the removal of aflatoxin from peanuts. Peanut Science, 29:128-136.

Whitaker, T.B. 2003. Standardization of mycotoxin sampling procedures: an urgent necessity. J. Food Control, 14:233-237.

Lamb, M.C., Blankenship, P.D., Whitaker, T.B., and Butts, C.L. 2003. A note on the accuracy and variability of grading and marketing high moisture farmer stock peanuts, Peanut Science, 30:94-99.

Whitaker, T.B., Trucksess, M.W., Giesbrecht, F.G., Slate, A.B., and Thomas, F.S. 2004. Evaluation of sampling plans to detect Cry9C protein in corn flour and meal. J. Assoc. Off. Analytical Chem., Int., 87:950-960.

Trucksess, M.W., Whitaker, T.B., Slate, A.B., Williams, K.M., Brewer, V.A., Whittaker, P., and Heeres, J.T. 2004. Variation of analytical results for peanuts in energy bars and milk chocolate. J. Assoc. Off. Analytical Chem., Int., 87:943-949.

Vargas, E.A., Whitaker, T.B., Santos, E.A., Slate, A.B., Lima, F.B., Franca, R.C.A. 2004. Testing green coffee for ochratoxin A, Part I: estimation of variance components, J. Assoc. Off. Analytical Chem., Int., 87:884-891.

Whitaker, T.B. 2004. Sampling for Mycotoxins, IN: Mycotoxins in Foods: Detection and Control, Eds: N. Magan and M. Olsen, Woodhead Publishing Limited, Cambridge, England, pp.69-87 (Book Chapter).

Adams, J. and Whitaker, T.B. 2004. Peanuts, aflatoxin, and the U.S. origin certification program, IN: Meeting the Mycotoxin Menace, Eds: D. Barug, H. van Egmond, R. Lopez-Garcia, T. van Osenbruggen, and A. Visconti, Wageningen Academic Publishers, Den Haag, The Netherlands, pp183-196 (Proceedings of the Second World Mycotoxin Forum, Feb. 2003).

Whitaker, T.B., Dorner, J.W., Giesbrecht, F.G., and Slate, A.B. 2004. Variability among aflatoxin test results on runner peanuts harvested from small field plots, Peanut Science, 31:59-63.

Whitaker, T.B. 2005. Sampling feeds for mycotoxin analysis, IN: The Mycotoxin Blue Book, Ed: D. Diaz, Nottingham University Press, Nottingham, United Kingdom, pp. 1-23 (Book Chapter).

Whitaker, T.B., Williams, K.M., Trucksess, M.W., and Slate, A.B. 2005. Immunochemical analytical methods for the determination of peanut proteins in foods, J. Assoc. Official Analytical Chem., Int., 88:161-174.

Whitaker, T.B. and Johansson, A.S. 2005. Sampling uncertainties for the detection of chemical agents in complex food matrices. Journal of Food Protection, 68:1306-1313.

Vargas, E.A., Whitaker, T.B., Santos, E.A., Slate, A.B., Lima, F.B., and Franca, R.C.A. 2005. Testing green coffee for ochratoxin A, Part II: observed distribution of ochratoxin A test results, J. Assoc. Official Analytical Chem., 88:780-787.

Whitaker, T.B. 2006. Sampling foods for mycotoxins. Journal Food Additives and Contaminates, 23:50-61.

Vargas, E.A., Whitaker, T.B., Santos, E.A., Slate, A.B., Lima, F.B., and Franca, C.A. 2006. Design of sampling plans to detect ochratoxin A in green coffee, J. Food Additives and Contaminates, 23:62-72.

Johansson, A.J., Whitaker, T.B., Hagler, W.M., Bowman, D.T., Slate, A.B., and Payne, G. 2005, Predicting aflatoxin and fumonisin in shelled corn lots using poor quality grade components, J. Assoc. Official Analytical Chem., Int., 89:433-440.

Whitaker, T.B., Slate, A.B., Jacobs, M., Hurley, J.M., Adams, J.G., and Giesbrecht, F.G. 2005, Sampling almonds for aflatoxin, Part I: Estimation of uncertainty associated with sampling, sample preparation, and analysis, J. Assoc. Official Analytical Chem., Int., 89:1027-1034.

Ozay, G., Seyhan, F., Yilmaz, A. Whitaker, T.B., and Slate, A.B. 2005. Sampling hazelnuts for aflatoxin, Part I: Estimation of uncertainty associated with sampling, sample preparation, and analysis, J. Assoc. Official Analytical Chem., Int., 89:1004-1011.

Research Presentations (by invitation)

Invited to make 100 presentations at regional, national, and international meetings and to author or coauthor 14 book chapters. The most significant invitations are listed below.

Invited to make 4 presentations to 3 International Union of Pure and Applied Chemistry (IUPAC) meetings, “Sampling granular foodstuffs for aflatoxin” and “Errors associated with sampling and sample preparation,” Third Annual Mycotoxin Symposium, Paris, France, 1976; “Sampling shelled corn for fumonisin,” (Plenary Speaker) Sao Paulo, Brazil, 2000; “Sampling green coffee for ochratoxin A”, Bethesda, MD, 2004.

Invited presentation, “The effects of methanol concentration and solvent/peanut ratio on the extraction of aflatoxin from raw peanuts,” made to the A. D. Campbell Memorial Session of the Association of Official Analytical Chemists (AOAC), Washington, DC, 1982.

Invited by CAST to assist in 2 CAST Task Force Reports, #s 116 and 139 concerning mycotoxins: invited to write a chapter on sampling foods for mycotoxins, 1989 ; invited to be a member of CAST Task Force Team and help identify authors, review documentation, and publish CAST mycotoxin document, 2004.

Invited to make a presentation, “Problems associated with testing agricultural commodities for aflatoxin: Errors in sampling, sample preparation, and analysis,” to an aflatoxin symposium sponsored by the National Program Staff, USDA-ARS for the US House Committee on Agriculture, Washington, DC, 1990.

Invited by Association of Official Analytical Chemists, International (AOAC) to assist with 2 Journal initiatives: to be a Guest Editor and solicit, review, and publish a collection of manuscripts on sampling foods for mycotoxins, 1999; to be the Associate Referee for Sampling to monitor and document in the AOAC journal all new research developments in sampling foods for mycotoxins, 1995.

Invited by FAO/WHO to be a member of 3 Expert Consultations. Expert consultation to develop aflatoxin sampling plans for peanuts and shelled corn, 1993; Member of Joint Expert Committee on Food Additive (JECFA) to determine human risks to five mycotoxins in food products, FAO/WHO, 2000; reappointed member JECFA in 2004.

Invited to make a series of nine lectures, “Detecting aflatoxin contaminated lots: sampling, sample preparation and analysis” to the VI Argentina Food Science and Technology Congress, Buenos Aires, Argentina, 1994.

Invited to make presentation, “Sampling agricultural commodities for mycotoxins,” FDA/USDA Interagency Conference on Mycotoxins, Washington, DC, 1997.

Invited to testify before a US House Agricultural Subcommittee about the pros and cons associated with replacing the current visual method of inspecting farmers’ stock peanuts for mold with a direct measure of aflatoxin, Dothan, AL, 1998.

Invited by FDA to give a 2-hour lecture concerning the sampling of agricultural commodities for aflatoxin to FDA field inspectors at an FDA workshop, Atlanta, GA, 1999.

Invited to present “Sampling shelled corn for fumonisin,” FDA Fumonisin Workshop, University of Maryland, 2000.

Invited to present “Sampling grain for GMO seed,” USDA/GIPSA Biotech Workshop, Kansas City, MO, 2000.

Invited by the First and Second World Mycotoxin Forums, 2001 and 2003 to make presentations: “Standardization of Sampling Plans: An Urgent Necessity”, plenary speaker), and “Peanuts, aflatoxin, and the origin certification program” , Noordwijk, The Netherlands, 2001 and 2003.

Invited by Wilda Martinez to be a member of an USDA/ARS TCK Task Force Team. As a member of international experts, helped to develop a TCK Pest Risk Assessment Model, 1997. Made 5 presentations over a 5-year period concerning the design and evaluation of sampling plans to detect TCK in export wheat to China. These presentations were made to Chinese government officials, Portland Oregon, 1997; USDA/FAS, USDA/GIPSA, USDA/ARS, and wheat industry representatives, Washington, DC, 1998; Chinese government officials, Beltsville, MD, 2001 and 2002.

Invited by the International Atomic Energy Agency of the UN to and deliver 6-hour lecture to Mycotoxin Training Workshop Workshop on “Sources of uncertainty when testing agricultural commodities for mycotoxins”, Vienna, Austria, 2002.

Invited by the FDA to be a member of a Food Advisory Committee to reviewed action plan developed by FDA to address the issue of acrylamide in foods, College Park, MD, 2002.

Invited by FDA and BARD to a Science and Technology Based Countermeasures to Foodborne Terrorism Conference to present “Sampling uncertainties for the estimation of chemical agents in complex food matrices”, Shepherdstown, WV, 2003.

Invited by Assoc. Off. Analytical Chem. Annual Meeting, to make keynote address at the Harvey W. Wiley Symposium as recipient of the 2003 Wiley Award, “Differences in uncertainty when sampling commodities for mycotoxins”, Atlanta, GA, 2003.

Invited by the European Commission, Directorate General for Food Safety to make two presentations “Sampling foods for mycotoxins” and “Sampling green coffee for ochratoxin A” to delegates from the 25 EU member states, Brussels, Belgium, 2004.

Invited by the Brazil Ministry of Agriculture to make 2 presentations “Sampling foods for mycotoxins” and “Sampling green coffee for ochratoxin A” at a Sampling Workshop, Bella Horizonte, Brazil, 2004.

Invited by the Dried Fruits Association of California to present “Errors associated with sampling treenuts for aflatoxin” at a DFA/European Commission Workshop on Aflatoxin Control, 2005.

Invited by American Chemical Society to make two presentation “Sampling treenuts for aflatoxin” at mycotoxin symposium in San Francisco, 2006.

Introduction to Sampling Plan Design and Performance Considerations Definition of a Sampling Plan It is important to be able to detect and quantify the mycotoxin concentration in foods and feeds destined for human and animal consumption. In research, quality assurance, and maximum activities, correct decisions concerning the fate of commercial lots can only be made if the mycotoxin concentration in the lot can be made with a high degree of accuracy and precision. The mycotoxin concentration of a bulk lot is usually estimated by measuring the concentration in a small portion of the lot or a sample taken from the lot (Figure 1). Lot (50,000 kg) PPB=? Sample (2 kg) ppb • Lot PPB = Sample ppb ? • ppb ≤ Limit ? Figure 1. Lot mycotoxin concentration is assumed to equal the measure mycotoxin concentration in a small sample. The mycotoxin concentration in the bulk lot is assumed to be the same as the measured mycotoxin concentration in the sample. Then based on the measured sample concentration, some decision is made about the edible quality of the bulk lot or the effect of a treatment or a process on reducing the mycotoxin concentration in the lot. For example, decisions will be made to classify the lot as acceptable or unacceptable based upon a comparison of the measured sample.

concentration to a maximum limit. If the sample concentration does not accurately reflect the lot concentration, then the lot may be misclassified and there may be undesirable economic and/or health consequences. Fortunately, sampling plans can be designed to minimize the misclassification of lots and reduce the undesirable consequences associated with decisions about the fate of bulk lots. A sampling plan is defined by a mycotoxin test procedure and a defined accept/reject limit. A mycotoxin test procedure is a multi-stage process (Figure 2) and generally consists of three steps: sampling, sample preparation, and analysis (quantification). Lot Test Procedure Test Result Mill Sample	Sample	Analysis Preparation Figure 2. A mycotoxin test procedure usually consists of a sampling, sample preparation and analytical step. The sampling step specifies how the sample will be selected or taken from the bulk lot, the number of samples, and the size of the sample(s). For granular products, the sample preparation step is also a two-part process where the sample is ground in a mill to reduce particle size and an analytical subsample is removed from the comminuted sample. Finally in the analytical step, the solvent extracted from the comminuted analytical subsample is quantified using approved analytical procedures. The measured mycotoxin concentration in the sample is used to estimate the true mycotoxin concentration in the bulk lot or compared to a defined accept/reject limit that is usually equal to a maximum limit. Comparing the measured mycotoxin concentration in the sample to an accept/reject limit is often called acceptance sampling because the measured concentration value is not as important as whether the measured mycotoxin concentration (and thus the lot mycotoxin concentration) is above or below a maximum limit. In food processing activities, a precise and accurate estimate of the true lot concentration becomes important. Designing sampling plans Because of the variability among sample test results, two types of mistakes are associated with any sampling plan. First, good lots (lots with a true mycotoxin concentration less than or equal to the maximum limit) will test bad and be rejected by the sampling plan. The chances of making this type of mistake is often called the sellers’ risk (false positives) since these lots will be rejected at an unnecessary cost to the seller of the product. Secondly, bad lots (lots with a mycotoxin concentration greater than the maximum limit) will test good and be accepted by the sampling program. The chances of making this type of mistake is called the buyers’ risk (false negatives) since contaminated lots will be processed into feed or food causing possible health problems and/or economic loss to the buyer of the product. In order to maintain an effective quality control program, the above two risks associated with a sample plan design must be evaluated (Figure 3) and minimized to acceptable levels. Based upon these evaluations, the costs and benefits (benefits refers to removal of mycotoxin contaminated lots) associated with a mycotoxin sampling plan need to be evaluated.

GOOD GLA GLR	x (Seller’s Risk) 0 BAD BLA	x (Buyer’s Risk) Limit ppb Figure 3. Four possible outcomes when classifying lots as good or bad. Good lots rejected (GLR) and bad lots accepted (BLA) are incorrect decisions. Good lots accepted (GLA) and bad lots rejected (BLR) are correct decisions. A lot is termed bad when the sample test result Cs is above some predefined accept/reject limit Ca and the lot is termed good when Cs is less than or equal to Ca. While Ca is usually equal to the maximum limit CL, Ca can be greater than or less than CL. For a given sample design, lots with a concentration C will be accepted with a certain probability P(C)=prob(Cs < Ca | C) by the sampling plan. A plot of P(C) versus the lot concentration C is called an operating characteristic (OC) curve. Figure 4 depicts the general shape of an OC curve.

100 90 80 70 60 50 40 30 20 10 00 Lot Mycotoxin Concentration - C (ng/g) Good lots rejected (Sellers' risk) Cs<=CL (good lots) Cs>CL (bad lots) Bad lots accepted (Buyers' risk) Figure 4. General shape of an operating characteristic (OC) curve. The shape of the OC curve is unique for an mycotoxin test procedure and indicates the magnitude of the buyers’ and sellers’ risks. As C approaches 0, P(C) approaches 1 or 100%, and as C becomes large, P(C) approaches zero. Lots with little to no contamination (C =0) are accepted by the sampling plan 100% of the time; lots with very high levels of contamination (C = large) are never accepted (rejected 100% of the time) by the sampling plan; lots with contamination levels near the accept/reject limit are accepted by the sampling plan less than 100% of the time. The shape of the OC curve is uniquely defined for a particular sampling plan design with designated values of sample size, degree of comminution, subsample size, type analytical method, and number of analyses, and the accept/reject limit Ca.

Increasing Sample Size - Reducing the variability or uncertainty associated with the mycotoxin test procedure will reduce the number of lots misclassified and thus reduce both the buyers’ risk and the sellers’ risk. The uncertainty of the mycotoxin test procedure can be reduced by increasing sample size, grinding the sample into smaller particles, increasing the analytical subsample size, quantifying more aliquots, and using a more precise analytical method such as LC instead of TLC. Because the sampling step accounts for a large portion of the total variability, it is more effective to reduce uncertainty of the mycotoxin test procedure by increasing sample size. Changing Accept/reject Limit – Changing the accept/reject limit relative to the maximum limit can also be used to reduce either the sellers’ risk or the buyers’ risk, but not both risks at the same time. When the accept/reject limit is equal to the maximum limit, both the buyer and the seller share in the risks associated with the sampling plan. If the accept/reject limit is reduced to a value below the maximum limit, the OC curve shifts to the left and the area representing the sellers’ risk increases and the buyers’ risk decreases. If the accept/reject limit is larger than the maximum limit, the OC curve shifts to the right and the area representing the buyers’ risk increases and the sellers’ risk decreases. Multiple Samples - Increasing the number of samples of a given size taken from a contaminated lot reduces the risks associated with classifying lots. If the mycotoxin concentration among all sample test results is averaged, the effect is the same as increasing sample size. However, if all sample test results are required to test less than the accept/reject limit, the effect on the OC curve 6 is very different from averaging multiple sample test results. As the number of samples required to test less than or equal to the accept/reject limit increases, the OC curve shifts to the left reducing the buyers’ risk but increasing the sellers’ risk. The result is similar to reducing the accept/reject limit relative to the maximum limit. This type of sampling plan is often used late in the marketing system on finished product destined for animal or human consumption because the product has a smaller chance of containing a concentration above the maximum limit. The buyer is placing most of the risk on the sell of the product. Links: Performance of Aflatoxin Sampling Plan Designs for Treenuts OC Curves for Almonds OC Curves for Hazelnuts OC Curves for Pistachio Nuts