@article{ozer_basegmez_whitaker_slate_giesbrecht_2017, title={Sampling dried figs for aflatoxin - Part 1: variability associated with sampling, sample preparation, and analysis}, volume={10}, ISSN={["1875-0796"]}, DOI={10.3920/wmj2016.2052}, abstractNote={The variability associated with the aflatoxin test procedure used to estimate aflatoxins in bulk shipments of dried figs was investigated. Sixteen 10 kg laboratory samples were taken from each of twenty commercial bulk lots of dried figs suspected of aflatoxin contamination. Two 55 g test portions were taken from each comminuted laboratory sample using water-slurry comminution methods. Finally, two aliquots from the test portion/solvent blend were analysed for both aflatoxin B1 and total aflatoxins. The total variance associated with testing dried figs for aflatoxins was measured and partitioned into sampling, sample preparation and analytical variance components (total variance is equal to the sum of the sampling variance, sample preparation variance, and analytical variance). Each variance component increased as aflatoxin concentration increased. Using regression analysis, mathematical expressions were developed to model the relationship between aflatoxin concentration and the total, sampling, sample pr...}, number={1}, journal={WORLD MYCOTOXIN JOURNAL}, author={Ozer, H. and Basegmez, H. I. Oktay and Whitaker, T. B. and Slate, A. B. and Giesbrecht, F. G.}, year={2017}, pages={31–40} }
 @article{whitaker_slate_nowicki_giesbrecht_2016, title={Variability and distribution among sample test results when sampling unprocessed wheat lots for ochratoxin A}, volume={9}, ISSN={["1875-0796"]}, DOI={10.3920/wmj2015.1970}, abstractNote={In 2008, Health Canada announced it was considering the establishment of maximum levels for ochratoxin A (OTA) in unprocessed wheat, oats, and their products. The Canada Grains Council and Canadian National Millers Association initiated two studies to measure the variability and distribution among sample test results for unprocessed wheat and oats so that scientifically based OTA sampling plans could be designed to meet regulatory and industry requirements. Sampling statistics related to detecting OTA in oats has been published. 54 OTA contaminated wheat lots representing three wheat classes were identified for the sampling study. Each lot was sampled according to a nested experimental protocol where sixteen 2-kg laboratory samples were taken from each lot, multiple 5-g test portions were taken from each comminuted 2-kg laboratory sample, and multiple OTA measurements were made on each test portion using liquid chromatography. The sampling, sample preparation, and analytical variances associated with each step of the OTA test procedure were found to be a function of OTA concentration and regression equations were developed to predict the functional relationships between variance and OTA concentration. When sampling a wheat lot containing 5 µg/kg OTA with an OTA test procedure consisting of a sampling step employing a single 2-kg laboratory sample, sample preparation step employing a single 100-g test portion, and an analytical step that used liquid chromatography to quantify OTA, the sampling step accounted for 95.3% of the total variability. The observed OTA distribution among the 16 OTA sample results was found to be positively skewed and the negative binomial distribution was selected to model the OTA distribution among sample test results. The sampling statistics were incorporated into the FAO Mycotoxin Sampling Tool and the chances of rejecting good lots and accepting bad lots were calculated for various sampling plan designs.}, number={2}, journal={WORLD MYCOTOXIN JOURNAL}, author={Whitaker, T. B. and Slate, A. B. and Nowicki, T. W. and Giesbrecht, F. G.}, year={2016}, pages={163–178} }
 @article{whitaker_slate_nowicki_giesbrecht_2015, title={Variability and distribution among sample test results when sampling unprocessed oat lots for ochratoxin A}, volume={8}, ISSN={["1875-0796"]}, DOI={10.3920/wmj2014.1858}, abstractNote={In 2008, Health Canada announced it was considering the establishment of maximum levels for ochratoxin A (OTA) in a number of foods, including unprocessed wheat and oats and their products. The Canada Grains Council and Canadian National Millers Association initiated a study to measure the variability and distribution among sample test results so that scientifically based sampling plans could be designed to meet regulatory and industry requirements. Twenty lots of oats naturally contaminated with OTA were identified and sampled according to a nested experimental protocol where 16-two kg laboratory samples were taken from each lot, two 100 g test portions were taken from each comminuted laboratory sample, and two aliquots of the extract from each test portion were analysed for OTA by LC. The variance associated with each step of the OTA test procedure were found to be a function of OTA concentration and regression equations were developed to predict the functional relationship. When using the above OTA tes...}, number={4}, journal={WORLD MYCOTOXIN JOURNAL}, author={Whitaker, T. B. and Slate, A. B. and Nowicki, T. W. and Giesbrecht, F. G.}, year={2015}, pages={511–524} }
 @article{stagg_amato_giesbrecht_lanier_2012, title={Autolytic Degradation of Skipjack Tuna during Heating As Affected by Initial Quality and Processing Conditions}, volume={77}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2011.02543.x}, abstractNote={UNLABELLED
Several factors were studied as affecting protein degradation and texture of skipjack tuna muscle following ambient pressure thermal processing (precooking). These included degree of mushy tuna syndrome (MTS) evidenced in the raw meat, raw meat pH, abusive thawing/holding, and precooking temperature/time. Slurries and intact pieces from frozen skipjack tuna, either tempered for 2 h or thawed and held at 25 °C for 22 h (abusive treatment) were heated at temperatures ranging from 40 to 80 °C for up to 2 h, and also at 90 °C for 1 h, with or without prior adjustment of pH to 5 or 7 to favor cathepsin or calpain activity, respectively. Proteolysis of precooked samples was monitored by Lowry assay and SDS-PAGE; cooked texture of intact meat was measured using a Kramer shear press and by sensory profile analysis. Proteolysis maximally occurred in slurries of skipjack tuna muscle that had been abusively stored (22 h at 25 °C) and adjusted to pH 5 prior to heating at 55 °C. Intact pieces of tuna abusively thawed/held for 22 h with subsequent heating at 55 °C also evidenced the most proteolysis and were the least firm in texture. Raw fish that evidenced higher severity of MTS when raw displayed higher levels of proteolysis prior to cooking, which were further increased after cooking at 55 °C.


PRACTICAL APPLICATION
The kinetic data presented here can be used to optimize processing conditions for skipjack tuna canning to minimize textural degradation and optimize quality.}, number={2}, journal={JOURNAL OF FOOD SCIENCE}, author={Stagg, Nicola J. and Amato, Penny M. and Giesbrecht, Francis and Lanier, Tyre C.}, year={2012}, month={Feb}, pages={C149–C155} }
 @article{whitaker_slate_adams_birmingham_giesbrecht_2010, title={Comparing the performance of sampling plans that use a single regulatory limit based upon total aflatoxins to sampling plans that use dual limits based upon B-1 and total aflatoxins}, volume={3}, ISSN={["1875-0796"]}, DOI={10.3920/wmj2009.1169}, abstractNote={The European Commission (EC) aflatoxin sampling plan for ready-to-eat tree nuts such as almonds requires that each of the three 10 kg laboratory samples must all test less than 2 ng/g aflatoxin B1 (AFB1) and 4 ng/g total aflatoxins (AFT) for the lot to be accepted. Exporters have observed that the AFB1/AFT ratio varied greatly from sample to sample and the ratio appeared to average more than 50%. Because of the concern that dual limits associated with the EC aflatoxin sampling plans may reject more lots than similar sampling plans that use a single limit based upon total aflatoxins, studies were designed with the objectives to (a) measure the distribution of AFB1/AFT ratio values using sample test results associated with testing U.S. almond lots exported to the European Union; (b) use Monte Carlo methods to develop a model to compute the effects of using dual limits based upon AFB1 and AFT on the probability of accepting almond lots; and (c) compare the probability of accepting almond lots using the curre...}, number={1}, journal={WORLD MYCOTOXIN JOURNAL}, author={Whitaker, T. B. and Slate, A. B. and Adams, J. G. and Birmingham, T. and Giesbrecht, F. G.}, year={2010}, month={Feb}, pages={35–44} }
 @article{trucksess_whitaker_weaver_slate_giesbrecht_rader_betz_2009, title={Sampling and Analytical Variability Associated with the Determination of Total Aflatoxins and Ochratoxin A in Powdered Ginger Sold As a Dietary Supplement in Capsules}, volume={57}, ISSN={["0021-8561"]}, DOI={10.1021/jf8017854}, abstractNote={The U.S. Food and Drug Administration is studying the need to monitor dietary supplements for mycotoxins such as total aflatoxins and ochratoxin A. An effective mycotoxin-monitoring program requires knowledge of the sampling and analytical variability associated with the determination of total aflatoxins (AF) and ochratoxin A (OTA) in dietary supplements. Three lots of ginger sold as a powder in capsule form and packaged in individual bottles were analyzed for both AF and OTA. The total variability associated with measuring AF and OTA in powdered ginger was partitioned into bottle-to-bottle, within bottle, and analytical variances. The variances were estimated using a nested design. For AF and OTA, the within-bottle variance associated with the 5 g laboratory sample size was the largest component of variability accounting for about 43% and 85% of the total variance, respectively; the analytical variance accounted for about 34% and 9% of the total variability, respectively; and the bottle-to-bottle variance accounted for about 23% and 7% of the total variance, respectively. When the total variance is converted into the coefficient of variation (CV or standard deviation relative to the mean concentration), the CV is lower for AF (16.9%) than OTA (24.7%).}, number={2}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Trucksess, Mary W. and Whitaker, Thomas B. and Weaver, Carol M. and Slate, Andrew and Giesbrecht, Francis G. and Rader, Jeanne I. and Betz, Joseph M.}, year={2009}, month={Jan}, pages={321–325} }
 @article{whitaker_slate_hurley_giesbrecht_2007, title={Sampling almonds for aflatoxin, Part II: Estimating risks associated with various sampling plan designs}, volume={90}, number={3}, journal={Journal of AOAC International}, author={Whitaker, T. B. and Slate, A. B. and Hurley, J. M. and Giesbrecht, F. G.}, year={2007}, pages={778–785} }
 @article{ozay_seyhan_yilmaz_whitaker_slate_giesbrecht_2007, title={Sampling hazelnuts for aflatoxin: Effect of sample size and accept/reject limit on reducing the risk of misclassifying lots}, volume={90}, number={4}, journal={Journal of AOAC International}, author={Ozay, G. and Seyhan, F. and Yilmaz, A. and Whitaker, T. B. and Slate, A. B. and Giesbrecht, F. C.}, year={2007}, pages={1028–1035} }
 @article{whitaker_slate_jacobs_hurley_adams_giesbrecht_2006, title={Sampling almonds for aflatoxin, part I: Estimation of uncertainty associated with sampling, sample preparation, and analysis}, volume={89}, number={4}, journal={Journal of AOAC International}, author={Whitaker, T. B. and Slate, A. B. and Jacobs, M. and Hurley, J. M. and Adams, J. C. and Giesbrecht, F. C.}, year={2006}, pages={1027–1034} }
 @article{ozay_seyhan_yilmaz_whitaker_slate_giesbrecht_2006, title={Sampling hazelnuts for aflatoxin: Uncertainty associated with sampling, sample preparation, and analysis}, volume={89}, number={4}, journal={Journal of AOAC International}, author={Ozay, G. and Seyhan, F. and Yilmaz, A. and Whitaker, T. B. and Slate, A. B. and Giesbrecht, F.}, year={2006}, pages={1004–1011} }
 @article{whitaker_trucksess_giesbrecht_slate_thomas_2004, title={Evaluation of sampling plans to detect Cry9C protein in corn flour and meal}, volume={87}, number={4}, journal={Journal of AOAC International}, author={Whitaker, T. B. and Trucksess, M. W. and Giesbrecht, F. G. and Slate, A. B. and Thomas, F. S.}, year={2004}, pages={950–960} }
 @article{isleib_pattee_giesbrecht_2004, title={Oil, sugar, and starch characteristics in peanut breeding lines selected for low and high oil content and their combining ability}, volume={52}, ISSN={["1520-5118"]}, DOI={10.1021/jf035465y}, abstractNote={Peanut seeds contain approximately 50% oil on a dry weight basis, making them a high fat food. Reduction of the oil content would make peanuts a more desirable food to fat conscious consumers. Removal of existing oil by processing is not feasible for in-shell peanuts, the dominant product of the North Carolina-Virginia area. To reduce oil content in in-shell peanuts, a genetic solution must be found. However, while reduced oil content is a desirable objective, changes in oil must not be accompanied by significant decreases in any of the desirable aspects of peanut flavor. Because the impact of selection for low or high oil on flavor is not known, it would be useful to know in what form dry matter is being stored in the seed, particularly if it is not being stored as oil. Screening of 584 accessions identified two lines (PI 269723 and PI 315608) with high and two (Robusto 2 and Robusto 3) with low oil contents, each pair differing in sugar content. The four parents were crossed in diallel fashion to investigate patterns of inheritance. General combining abilities (GCA) for oil content closely followed values of the parental lines. One low oil parent (Robusto 2) had a correspondingly elevated GCA for sugar content, but neither low oil parent had the effect of elevating starch in progeny. Reciprocal cross differences were found for starch and sugar contents, suggesting influences of cytoplasmic genes on those traits. These lines serve as resource material for researchers interested in the genetic and physiological aspects of the oil-sugar-starch relationship in peanuts.}, number={10}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Isleib, TG and Pattee, HE and Giesbrecht, FG}, year={2004}, month={May}, pages={3165–3168} }
 @book{giesbrecht_gumpertz_2004, title={Planning, construction, and statistical analysis of comparative experiments}, ISBN={0471213950}, DOI={10.1002/0471476471}, publisher={Hoboken, NJ: Wiley}, author={Giesbrecht, F. G. and Gumpertz, M. L..}, year={2004} }
 @article{whitaker_richard_giesbrecht_slate_ruiz_2003, title={Estimating deoxynivalenol in shelled corn barge lots by measuring deoxynivalenol in corn screenings}, volume={86}, number={6}, journal={Journal of AOAC International}, author={Whitaker, T. B. and Richard, J. L. and Giesbrecht, F. G. and Slate, A. B. and Ruiz, N.}, year={2003}, pages={1187–1192} }
 @article{burns_chamblee_giesbrecht_2002, title={Defoliation intensity effects on season-long dry matter distribution and nutritive value of tall fescue}, volume={42}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2002.1274}, abstractNote={Implementation of intensive grazing management requires knowledge about pasture growth rates and nutritive value throughout the grazing season. Such information is lacking because results from small-plot defoliation experiments generally focus on annual dry matter yields (DMYs) and season mean nutritive value. In this experiment, the influences of defoliation treatments on daily growth rate (DGR) and associated nutritive value of tall fescue (Festuca arundinacea Schreb.) throughout the growing season were evaluated. A 3-yr study was conducted on a Typic Kanhapludult soil near Raleigh, NC. Eight defoliation treatments (31-, 15-, 10- and 8-cm canopy heights cut to a 5-cm stubble; 31-, 15-, and 11-cm canopy heights cut to a 9-cm stubble, and an 8-cm canopy height cut to a 4-cm stubble) were evaluated in a randomized complete block design. Daily growth rates (kg ha -1 ) were significantly (P ≤ 0.01) altered by defoliation treatments and by years within treatments. When rainfall was near normal in both spring and late summer, tall fescue growth rates, depending on defoliation treatment, ranged from 34 to 55 kg ha -1 d -1 in May, from 7 to 18 kg ha -1 d -1 in late July, to 22 to 35 kg ha -1 d -1 in late September. In less favorable years, DGRs seldom exceeded 30 kg ha -1 d -1 in the spring or 15 to 30 kg ha -1 d -1 in the autumn. Depending on defoliation treatments, in vitro dry matter disappearance (IVDMD) ranged between 650 and 733 g kg -1 in the spring, 479 and 687 g kg -1 in midsummer, and 549 and 807 g kg -1 by late summer. Crude protein (CP) and detergent fiber fraction concentrations were also examined. The approach used to estimate DGR and associated nutritive value changes throughout the growing season resulted in useful data that can be applied in developing intensive grazing management practices.}, number={4}, journal={CROP SCIENCE}, author={Burns, JC and Chamblee, DS and Giesbrecht, FG}, year={2002}, pages={1274–1284} }
 @article{pattee_isleib_moore_gorbet_giesbrecht_2002, title={Effect of high-oleic trait and paste storage variables on sensory attribute stability of roasted peanuts}, volume={50}, ISSN={["0021-8561"]}, DOI={10.1021/jf025853k}, abstractNote={There has been much interest in the effect of the high-oleic acid trait of peanuts on various quality factors since discovery of high levels of oleic acid in a peanut mutant genotype. The trait provides greater oxidative stability for the high-oleic oil and seed. Several research groups have investigated high-oleic peanut oil and roasted peanut flavor characteristics, which were similar within high-oleic lines compared to Florunner. It was observed that some high-oleic lines derived from the Sunrunner cultivar have consistently higher predicted breeding values for roasted peanut attribute than Sunrunner itself. This study investigated if this apparent effect of the trait was an artifact arising from the handling procedures during processing and storage or from flavor fade. High-oleic lines used were derived by backcrossing the trait into existing cultivars, and the comparison of sensory attribute intensity was with the recurrent parent used in backcrossing. Previous comparisons have been between lines differing in more than just oleate content, that is, with widely different background genotypes that could contribute to the differences observed. Differential rates of change in sensory attributes were found in different background genotypes, suggesting that the comparison of high- and normal-oleic lines should be made in common background genotypes as well as in common production and postharvest environments. There was no measurable change in roasted peanut attribute in samples stored at -20 degrees C over the 63 day duration of this experiment. There were changes in roasted peanut in samples stored at 22 degrees C, confirming that storage at -20 degrees C is sufficient for large studies that require multiple sensory panel sessions over a period of weeks.}, number={25}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Pattee, HE and Isleib, TG and Moore, KM and Gorbet, DW and Giesbrecht, FG}, year={2002}, month={Dec}, pages={7366–7370} }
 @article{pattee_isleib_giesbrecht_cui_2002, title={Prediction of parental genetic compatibility to enhance flavor attributes of peanuts}, volume={829}, DOI={10.1021/bk-2002-0829.ch017}, abstractNote={As future advances in transformation technology allow insertion of useful genes into a broader array of target genotypes, the choice of targets will become more important. Targets should be genotypes that will pass to their progeny other useful characteristics, such as sensory quality characteristics, while improving agronomic performance or pest resistance. This is particularly important if flavor quality is to be maintained or improved as the transgene is moved into breeding populations via sexual transfer. Selection of genotypes with superior breeding values through the use of Best Linear Unbiased Prediction procedures (BLUPs) is discussed and using a database of sensory attributes on 250 peanut cultivars and breeding lines, the application of BLUP procedures to the selection of parents for improvement of roasted peanut and sweet attributes in breeding of peanut cultivars is illustrated.}, journal={Crop biotechnology  (ACS symposium series ; 829)}, publisher={Washington, DC: American Chemical Society}, author={Pattee, H. E. and Isleib, T. G. and Giesbrecht, F. G. and Cui, Z.}, editor={K. Rajasekaran, T. J. Jacks and Finley, J. W.Editors}, year={2002}, pages={217–230} }
 @article{whitaker_hagler_giesbrecht_johansson_2002, title={Sampling wheat for deoxynivalenol}, ISBN={0306467801}, DOI={10.1007/978-1-4615-0629-4_8}, abstractNote={The variability associated with testing wheat for deoxynivalenol (DON) was measured using a 0.454 kg sample, a Romer mill, 25 g of comminuted subsample and the Romer Fluoroquant analytical method. The total variability was partitioned into sampling, sample preparation, and analytical variability components. Each variance component was found to be a function of the DON concentration and equations were developed to predict each variance component using regression techniques. The effects of sample size, subsample size, and number of aliquots on reducing the variability of the DON test procedure were also determined. Using the test procedure described above, the coefficient of variation (CV) associated with testing wheat at 5 ppm DON was found to be 13.4%. The CVs associated with sampling, sample preparation, and analysis were 6.3, 10.0, and 6.3%, respectively. The sample variations associated with testing wheat are relatively small when compared to CVs associated with testing other commodities for other mycotoxins such as aflatoxin in peanuts. Even with the use of a small sample size (0.454 kg), the sampling variation was not the largest source of error as found in other mycotoxin test procedures.}, journal={Mycotoxins and food safety  (Advances in experimental medicine and biology; v. 504)}, publisher={New York: Kluwer Academic/Plenum Publishers}, author={Whitaker, T. B. and Hagler, W. M. and Giesbrecht, F. G. and Johansson, A. S.}, editor={J. W. DeVries, M. W. Trucksess and Jackson, L. S.Editors}, year={2002}, pages={73–83} }
 @article{pattee_isleib_gorbet_giesbrecht_2002, title={Selecton of alternative genetic sources of large-seed size in Virginia-type peanut: Evaluation of sensory, composition, and agronomic characteristics}, volume={50}, ISSN={["0021-8561"]}, DOI={10.1021/jf025601j}, abstractNote={Jenkins Jumbo, the ancestral source of large-seed size in the Virginia market type (Arachis hypogaea L.), has been shown to have a deleterious effect on flavor of peanut. The pervasiveness of Jenkins Jumbo in the ancestry of large-seeded germplasm contributes to the generally less intense roasted peanut flavor of U.S. cultivars of the Virginia market type. As a remedy to this problem, alternative sources of large-seed size were sought. Nine large-seeded selections, with NC 7 and Florunner as checks, were tested in replicated trials in North Carolina and Florida from 1996 to 1998. Pod yield, grade, weight of 100 seeds, and oil, sugar, and starch contents were measured. A descriptive sensory panel evaluated flavor attributes of a roasted sound mature kernel (SMK) sample from each plot. NC 7 scored low for sweet sensory attribute, high for bitter, and median for roasted peanut. UF714021, a multiline incorporating the Altika cultivar with several sister lines, had the best flavor profile of the large-seeded selections, but it did not have particularly large seeds relative to NC 7. The largest seeded selections were X90037 and X90053, both derived from Japan Jumbo. Flavor scores for X90037 were similar to those for NC 7 for roasted peanut (3.0 vs 2.9 flavor intensity units, fiu) and sweet (2.7 vs 2.6 fiu) but worse than NC 7 for bitter (3.3 vs 3.7 fiu) and astringent (3.5 vs 3.7 fiu). X90053 had intermediate values for roasted peanut and astringent, high value for sweet, and low for bitter. Other lines that had or were likely to have Jenkins Jumbo as a recent ancestor were generally poor in roasted flavor, supporting the hypothesis that ancestry from Jenkins Jumbo imparts poor flavor characteristics. With the exception of the unexpected relationship between astringent attribute and extra large kernel (ELK) content (r = 0.82, P < 0.01), there were no significant correlations between sensory attributes and the important agronomic traits: yield, meat, and ELK content. Among the nine large-seeded lines tested in this study, three appear to have greater potential for use as parents: 86x45B-10-1-2-2-b2-B, UF714021, and X90053.}, number={17}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Pattee, HE and Isleib, TG and Gorbet, DW and Giesbrecht, FG}, year={2002}, month={Aug}, pages={4885–4889} }
 @article{whitaker_hagler_johansson_giesbrecht_trucksess_2001, title={Distribution among sample test results when testing shelled corn lots for fumonisin}, volume={84}, number={3}, journal={Journal of AOAC International}, author={Whitaker, T. B. and Hagler, W. M. and Johansson, A. S. and Giesbrecht, F. G. and Trucksess, M. W.}, year={2001}, pages={770–776} }
 @article{unal_fleming_mcfeeters_thompson_breidt_giesbrecht_2001, title={Novel quantitative assays for estimating the antimicrobial activity of fresh garlic juice}, volume={64}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-64.2.189}, abstractNote={Novel agar diffusion and broth dilution assays were developed for quantitatively estimating the antimicrobial activity of fresh garlic juice. Bacteria found to be inhibited by garlic juice in agar diffusion assay included two gram-positive and five gram-negative species. Leuconostoc mesenteroides was not inhibited. Escherichia coli B-103 (HB101, with pJH101, ampicillin resistant, 100 microg ml(-1)) was inhibited and chosen as the standard culture for quantitative assays. The agar diffusion assay was based on the slope ratio method, where the slope of dose response for garlic juice was divided by the slope of dose response for methylmethane thiosulfonate (MMTSO2). Juice from fresh garlic varied in activity between 1.76 and 2.31 microg of MMTSO2 per mg of garlic juice. The activity of juice decreased during 11 months of storage of garlic cloves at 5 degrees C from 2.31 to less than 0.1 microg of MMTSO2 per mg of juice. The broth dilution assay also used the E. coli B-103 culture, which permitted selective enumeration of this bacterium when 100 microg ml(-1) of ampicillin was incorporated into the enumerating agar. Selective enumeration was essential since the garlic juice was not sterile and, thus, contained natural flora. Growth of E. coli was unaffected by 0.1%, delayed by 0.25%, and completely inhibited at 0.5 and 2% garlic juice in broth during 24 h of incubation at 37 micro C. The minimum inhibition concentration of garlic juice by broth dilution assay was, thus, estimated to be 0.5%, which is equivalent to 3.46 microg of MMTSO2 per mg of garlic juice by the agar diffusion assay.}, number={2}, journal={JOURNAL OF FOOD PROTECTION}, author={Unal, R and Fleming, HP and McFeeters, RF and Thompson, RL and Breidt, F and Giesbrecht, FG}, year={2001}, month={Feb}, pages={189–194} }
 @inbook{pattee_sanders_isleib_giesbrecht_2001, title={Peanut roast color and sensory attribute relationships}, DOI={10.1021/bk-2001-0775.ch013}, abstractNote={Peanut roasting develops not only a pleasing sensory flavor but also a pleasing color. In studying the genetic relationships between sensory attributes and peanut genotypes, roast color of the peanut paste test sample is an important source of variability that must be considered. Intensity of the roasted peanut sensory attribute has a quadratic relationship to CIELAB L* with an optimum for roast color at 58.7. Changes in roasted peanut, sweet, bitter, and astringent sensory attributes as roasting progresses are discussed as are the effects of peanut market-type on the intensity and rate of change in the sensory attributes. Differences in the roasted peanut quality of the peanut market-types point to the importance of cooperative efforts between plant breeders and food scientists to ensure that when new varieties are released they not only have superior agronomic characteristics but also maintain or improve upon the flavor quality characteristics.}, booktitle={Chemistry and physiology of selected food colorants}, publisher={Washington, DC: American Chemical Society}, author={Pattee, H. E. and Sanders, T. H. and Isleib, T. G. and Giesbrecht, F. G.}, editor={J. M. Ames and Hofmann, T. F.Editors}, year={2001}, pages={187–200} }
 @article{whitaker_freese_giesbrecht_slate_2001, title={Sampling grain shipments to detect genetically modified seed}, volume={84}, number={6}, journal={Journal of AOAC International}, author={Whitaker, T. B. and Freese, L. and Giesbrecht, F. G. and Slate, A. B.}, year={2001}, pages={1941–1946} }
 @article{whitaker_wu_peterson_giesbrecht_johansson_2001, title={Variability associated with the official USDA sampling plan used to inspect export wheat shipments for Tilletia controversa spores}, volume={50}, ISSN={["1365-3059"]}, DOI={10.1046/j.1365-3059.2001.00640.x}, abstractNote={The variability associated with estimating the true concentration of teliospores of dwarf bunt (Tilletia controversa) per 50 g of wheat (TC concentration) in an export wheat shipment was studied by measuring the TC concentration in 16 test samples (50 g) taken from each of 137 export shipments. The variability among the 16 TC test sample results, as measured by the standard deviation, was found to increase with TC concentration. The functional relationship was approximately linear in a full‐log plot and regression analysis was used to determine the coefficients of the regression equation. Using statistical theory, the regression equation was modified to predict the standard deviation among test sample sizes other than the 50 g size used in this study. The standard deviation and coefficient of variation associated with using a 50 g test sample to estimate the true TC concentration of a wheat shipment with 2000 spores per 50 g were estimated to be 1062·8 and 53·1%, respectively. Increasing test sample size to 1600 g reduced the standard deviation and coefficient of variation to 187·9 and 9·4%, respectively.}, number={6}, journal={PLANT PATHOLOGY}, author={Whitaker, TB and Wu, J and Peterson, GL and Giesbrecht, FG and Johansson, AS}, year={2001}, month={Dec}, pages={755–760} }
 @article{pattee_isleib_giesbrecht_mcfeeters_2000, title={Investigations into genotypic variations of peanut carbohydrates}, volume={48}, ISSN={["0021-8561"]}, DOI={10.1021/jf9910739}, abstractNote={Carbohydrates are known to be important precursors in the development of roasted peanut quality. However, little is known about their genotypic variation. A better understanding of the role of carbohydrates in roasted peanut quality requires first an understanding of the genotypic variation in the soluble carbohydrate components. Ion exchange chromatography was used to isolate 20 different carbohydrate components in 52 genotypes grown in replicated trials at two locations. Inositol, glucose, fructose, sucrose, raffinose, and stachyose were quantitated, and 12 unknown peaks were evaluated on the basis of the peak height of the unknown relative to the cellobiose internal standard peak height. Peaks tentatively identified as verbascose and ajugose could not be properly integrated because of tailing. Of the 18 carbohydrates that were estimated, 9 exhibited significant variation between test environments, 5 among market types, 14 among genotypes within market types, and 11 exhibited some significant form of genotype x environment interaction. Genotypes accounted for 38-78% of the total variation for the known components, suggesting that broad-sense heritability for these components is high. The observed high genotypic variation in carbohydrate components is similar to the high genotypic variation observed for the sweetness attribute in roasted peanuts, which raises the question regarding possible interrelationships. The establishment of such interrelationships could be most beneficial to peanut breeding programs to ensure the maintenance of flavor quality in future peanut varieties.}, number={3}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Pattee, HE and Isleib, TG and Giesbrecht, FG and McFeeters, RF}, year={2000}, month={Mar}, pages={750–756} }
 @article{park_whitaker_giesbrecht_njapau_2000, title={Performance of three pneumatic probe samplers and four analytical methods used to estimate aflatoxins in bulk cottonseed}, volume={83}, number={5}, journal={Journal of AOAC International}, author={Park, D. L. and Whitaker, T. B. and Giesbrecht, F. G. and Njapau, H.}, year={2000}, pages={1247–1251} }
 @article{pattee_isleib_giesbrecht_mcfeeters_2000, title={Relationships of sweet, bitter, and roasted peanut sensory attributes with carbohydrate components in peanuts}, volume={48}, ISSN={["0021-8561"]}, DOI={10.1021/jf9910741}, abstractNote={Certain roasted peanut quality sensory attributes have been shown to be heritable. Currently the only means of measuring these traits is the use of a trained sensory panel. This is a costly and time-consuming process. It is desirable, from a cost, time, and sample size perspective, to find other methodologies for estimating these traits. Because sweetness is the most heritable trait and it has a significant positive relationship to the roasted peanut trait, the possible relationships between heritable sensory traits and 18 carbohydrate components (inositol, glucose, fructose, sucrose, raffinose, stachyose, and 12 unknown peaks) in raw peanuts from 52 genotypes have been investigated. Previously reported correlations among sweet, bitter, and roasted peanut attributes were evident in this study as well. Where there was positive correlation of total sugars with sweetness, there also was positive correlation of total sugars with roasted peanut attribute and negative correlation of total sugars with bitterness and astringency. The expected generalized relationship of total sugars or sucrose to sweetness could not be established because the relationship was not the same across all market-types. Further work is needed to determine the nature of the chemical components related to the bitter principle, which appear to modify the sweet response and interfere with the sensory perception of sweetness, particularly in the Virginia market-type. Also, certain carbohydrate components showed significant relationships with sensory attributes in one market-type and not another. These differential associations demonstrate the complexity of the interrelationships among sweet, bitter, and roasted peanut sensory attributes. Within two market-types it is possible to improve the efficiency of selection for sweetness and roasted peanut quality by assaying for total carbohydrates. On the basis of the regression values the greatest efficiency would occur in the fastigiate market-type and then the runner.}, number={3}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Pattee, HE and Isleib, TG and Giesbrecht, FG and McFeeters, RF}, year={2000}, month={Mar}, pages={757–763} }
 @article{whitaker_hagler_giesbrecht_johansson_2000, title={Sampling, sample preparation, and analytical variability associated with testing wheat for deoxynivalenol}, volume={83}, number={5}, journal={Journal of AOAC International}, author={Whitaker, T. B. and Hagler, W. M. and Giesbrecht, F. G. and Johansson, A. S.}, year={2000}, pages={1285–1292} }
 @article{johansson_whitaker_hagler_giesbrecht_young_bowman_2000, title={Testing shelled corn for aflatoxin, Part I: Estimation of variance components}, volume={83}, number={5}, journal={Journal of AOAC International}, author={Johansson, A. S. and Whitaker, T. B. and Hagler, W. M. and Giesbrecht, F. G. and Young, J. H. and Bowman, D. T.}, year={2000}, pages={1264–1269} }
 @article{johansson_whitaker_giesbrecht_hagler_young_2000, title={Testing shelled corn for aflatoxin, Part II: Modeling the observed distribution of aflatoxin test results}, volume={83}, number={5}, journal={Journal of AOAC International}, author={Johansson, A. S. and Whitaker, T. B. and Giesbrecht, F. G. and Hagler, W. M. and Young, J. H.}, year={2000}, pages={1270–1278} }
 @article{johansson_whitaker_giesbrecht_hagler_young_2000, title={Testing shelled corn for aflatoxin, Part III: Evaluating the performance of aflatoxin sampling plans}, volume={83}, number={5}, journal={Journal of AOAC International}, author={Johansson, A. S. and Whitaker, T. B. and Giesbrecht, F. G. and Hagler, W. M. and Young, J. H.}, year={2000}, pages={1279–1284} }
 @article{whitaker_hagler_giesbrecht_1999, title={Performance of sampling plans to determine aflatoxin in farmers' stock peanut lots by measuring aflatoxin in high-risk- grade components}, volume={82}, number={2}, journal={Journal of AOAC International}, author={Whitaker, T. B. and Hagler, W. M. and Giesbrecht, F. G.}, year={1999}, pages={264–270} }
 @article{pattee_giesbrecht_isleib_1999, title={Sensory attribute variation in low-temperature-stored roasted peanut paste}, volume={47}, ISSN={["1520-5118"]}, DOI={10.1021/jf981063s}, abstractNote={Length of sample storage can become significant in sensory studies due to panel fatigue limitations and samples needed for a reasonable expectation of finding significant differences. In roasted peanut sensory studies samples are stored between -10 and -23 degrees C to prevent or retard changes. Studies of up to 13 months' duration have examined stability and slow-rate sensory changes. Sweet taste was relatively stable, whereas bitter and tongue burn attributes increased slightly. Stale taste increased, suggesting lipid oxidation was taking place even at -23 degrees C. Painty attribute did not increase until stale was >3. An increase in fruity attribute was unexpected. With increases in fruity and stale attributes a decrease in roasted peanut was expected. However, storage at -23 degrees C seems to stabilize the roasted peanut lability when compared to storage at -10 degrees C. Fruity and stale interactions with roasted peanut and lability of roasted peanut were shown to be three separate and identifiable effects on roasted peanut.}, number={6}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Pattee, HE and Giesbrecht, FG and Isleib, TG}, year={1999}, month={Jun}, pages={2415–2420} }
 @article{whitaker_hagler_giesbrecht_dorner_dowell_cole_1998, title={Estimating aflatoxin in farmers' stock peanut lots by measuring aflatoxin in various peanut-grade components}, volume={81}, number={1}, journal={Journal of AOAC International}, author={Whitaker, T. B. and Hagler, W. M. and Giesbrecht, F. G. and Dorner, J W. and Dowell, F. E. and Cole, R. J.}, year={1998}, pages={61–67} }
 @article{giesbrecht_whitaker_1998, title={Investigations of the problems of assessing aflatoxin levels in peanuts}, volume={54}, ISSN={["0006-341X"]}, DOI={10.2307/3109780}, abstractNote={In this study, a number of probability distributions that have been used to model the occurrence of aflatoxin in peanuts are compared. Two distributions, the compound gamma and the negative binomial, are shown to have special appeal in that both can be justified by reasoning from the fundamental biological and stochastic processes that generate the aflatoxin. Since method of moments and maximum likelihood give consistent estimates of parameters in both models, practical considerations suggest using the former. One hundred twenty data sets, each consisting of fifty observations, were not sufficient to provide goodness-of-fit tests to establish either as superior to the other as a model. Both models fit the data well, appreciably better than other models examined. An attractive aspect of the compound gamma and the negative binomial distributions is that, as a consequence of their theoretical underpinnings, both involve parameters that have meaningful interpretations. In the compound gamma, the alpha parameter reflects the shape of the kernel-to-kernel aflatoxin content distribution, the lambda parameter reflects the number (or frequency) of contaminated kernels in the sample, and the beta parameter is a scale parameter. In the negative binomial, the two parameters can be used as measures of mean or location and shape.}, number={2}, journal={BIOMETRICS}, author={Giesbrecht, FG and Whitaker, TB}, year={1998}, month={Jun}, pages={739–753} }
 @article{whitaker_trucksess_johansson_giesbrecht_hagler_bowman_1998, title={Variability associated with testing shelled corn for fumonisin}, volume={81}, number={6}, journal={Journal of AOAC International}, author={Whitaker, T. B. and Trucksess, M. W. and Johansson, A. S. and Giesbrecht, F. G. and Hagler, W. M. and Bowman, D. T.}, year={1998}, pages={1162–1168} }