bluuebunny/crossref_metadata_2025 huggingface dataset:
CONSTRUCTION AND GROWTH KINETICS OF A BIOLUMINESCENT METHIONINE AUXOTROPH ESCHERICHIA COLI STRAIN FOR POTENTIAL USE IN A METHIONINE BIOASSAY
Authors: FROELICH C.A. , DÍAZ I.B. ZABALA , RICKE S.C.
Published: May 2007

Methionine is one of the essential and first limiting amino acids in animal nutrition. In this study, an Escherichia coli methionine auxotroph bacterial strain that exhibits a linear growth response to methionine concentrations was transformed with a plasmid containing genes encoding ampicillin resistance and bioluminescence in order to develop a microbiological technique for methionine quantitation. Transformants were selected based on antibiotic resistance and plasmid containing candidates were confirmed by restriction enzyme digestion and gel electrophoresis. To confirm the bioluminescent phenotype, video imaging of the strain using long exposure photography yielded colonies exhibiting bioluminescence. The strain was also tested in the presence of ampicillin supplemented media with increasing methionine concentrations and growth response (measured as optical density, OD), growth rates and methionine affinities were compared before and after transformation. Although the transformed E. coli methionine auxotroph exhibited somewhat different growth kinetic responses than the nontransformed strain, the standard curves used for estimating methionine concentrations were not different. Based on the results in this study the transformed bioluminescent strain could be used as an OD‐based assay if bioluminescence equipment and materials are not available.
PCR‐BASED FLUORESCENT METHOD FOR RAPID DETECTION OF SALMONELLA TYPHIMURIUM IN POULTRY SAMPLES
Authors: WANG HONG , LI YANBIN , SLAVIK MICHAEL
Published: May 2007

A DNA binding fluorescence method based on polymerase chain reaction (PCR) products was evaluated for rapid detection of Salmonella Typhimurium in poultry products. Wash water samples of chicken carcasses and ground turkey were inoculated with S. Typhimurium to obtain final concentrations of 10° ‐ 105 CFU/mL. One mL of each sample was used to get the DNA template and 5 μL of the sample template was added into 25 μL of SYBR Green PCR Master Mix and two specific Salmonella ompC gene primers. The negative control was the same except 5 μL of each wash solution was added instead of 5 μL sample template. The reaction was carried out in a thermocycler. Finally, the fluorescence signal of each PCR product was measured using a fluorometer. The PCR products were also confirmed by ethidium bromide agarose gel, and the DNA concentrations of the PCR products were measured by a filter fluorescence photometer. The results showed that when bacterial cells increased from 0 to 2 CFU/mL, the fluorescence signal increased significantly. The PCR‐based fluorescence method could detect the target bacteria in minutes after PCR amplification compared to hours by gel electrophoresis and also could be done at an earlier time during PCR amplification. The detection limit of this method for S. Typhimurium in the poultry samples was 2 CFU/mL without any enrichment.
RECOVERY OF ESCHERICHIA COLI O157:H7 FROM FIBER OPTIC WAVEGUIDES USED FOR RAPID BIOSENSOR DETECTION
Authors: KRAMER MARIANNE F. , TIMS THOMAS B. , DeMARCO DANIEL R. , LIM DANIEL V.
Published: May 2007

Consumption of ground beef has been implicated in the majority of outbreaks of disease from Escherichia coli O157:H7. There is a great need for rapid, sensitive, and specific microbial detection and isolation methods for the detection and recovery of pathogens such as E. coli O157:H7. Evanescent wave, fiber optic biosensors are an innovative, cutting‐edge technology with the potential to meet such a need. Food pathogens such as E. coli O157:H7 can be detected in minutes using the biosensor assay rather than days using conventional methods. The biosensor assay is sensitive and presently has the ability to directly detect 102 CFU of E. coli O157:H7 in E. coli O157:H7‐seeded PBS or ground beef. In this study, it was determined that once the pathogen had been positively identified, it could then be recovered by culturing the cells captured on the waveguide used in the biosensor assay. E. coli O157:H7‐seeded PBS or ground beef samples were assayed using an evanescent wave, fiber optic biosensor. After a positive identification on the biosensor, the waveguide was added to modified LB medium supplemented with 10 μg/mL acriflavin (mLB) and incubated at 42C for a minimum of 4 h followed by selection on Rainbow O157 agar incubated 16 to 18 h at 37C. E. coli O157:H7 was confirmed using agglutination with E. coli O157:H7 antiserum. It was possible to recover E. coli O157:H7 colonies in E. coli O157:H7‐seeded PBS or ground beef when 1 mL samples containing at least 2.0 × 103 CFU of E. coli O157:H7 had been injected into the biosensor. It took only 24 h to detect the target pathogen, recover the pathogen from the sample, and grow isolated colonies. This total time included sample preparation, detection, enrichment culture, and growth of cells to produce isolated colonies on a selective and differential medium. The identification of isolated colonies was then quickly confirmed using slide agglutination with the appropriate antiserum. This method significantly improved the speed of the confirmation of the presence of the pathogen and of the isolation of the pathogen, from 4 days using conventional methods to one day using the biosensor assay.
ASSESSMENT OF LABORATORY MEDIA CONTROLS FOR DETERMINING SALMONELLA VIRULENCE POTENTIAL OF POULTRY WATER SOURCES USING A HILA:LACZY FUSION STRAIN
Authors: NUTT J.D. , MEDVEDEV K.L. , WOODWARD C.L. , PILLAI S.D. , RICK S.C.
Published: May 2007

Salmonella is regarded as a primary foodborne pathogen commonly found in the gastrointestinal tract and internal organs of poultry. However, Salmonella is also capable of surviving in fresh water supplies. In this study, our efforts were to determine which media controls of varying nutrient availability would allow for accurately assessing the potential of a poultry house water source to influence virulence gene expression in Salmonella. The cages of the sampled layer house were divided into four separate quadrants. Virulence expression was measured using a β‐galactosidase assay on a hilA:lacZY fusion strain of S. Typhimurium and calculated as Miller units to adjust for bacterial cell concentration measured as optical density. Virulence assays were performed with brain heart infusion broth (BHI) serving as the primary overall control which yielded values ranging from approximately 60–100 Miller units. Results showed that standing water obtained from quadrant 2 yielded a significantly different (P<0.05) virulence responses compared to other standing water samples from other quadrants. However, no significant difference was observed between the quadrants for the fresh water samples. BHI media proved to be the most consistent negative control for evaluating hilA response to poultry house water by yielding the lowest overall Miller unit values compared to other laboratory control media.
APPLICATION OF A TRANSPOSON FOOTPRINTING TECHNIQUE FOR RAPID IDENTIFICATION OF SALMONELLA TYPHIMURIUM TN5 MUTANTS REQUIRED FOR SURVIVAL UNDER DESICCATION STRESS CONDITIONS
Authors: PARK S.Y. , KWON Y.M. , BIRKHOLD S.G. , KUBENA L.F. , NISBET D.J. , RICKE S.C.
Published: May 2007

Salmonella spp. are one of the foodborne pathogens that can be isolated in the environments of poultry houses and desiccation is a potential stress condition that can influence the survival of Salmonella spp. in this environment. In order to investigate the desiccation survival mechanism of Salmonella spp. the genome of S. typhimurium ATCC 14028 was screened for the genes potentially required for survival during desiccation using a novel method based on Tn5 mutagenesis previously developed in our laboratory. This method, termed transposon footprinting, simultaneously amplifies the Tn5‐flanking sequences in a complex pool of the Tn5 mutants. As the length of the amplified DNA fragment should be unique for each distinct Tn5 mutant, the polymerase chain reaction (PCR) products separated on an agarose gel generate transposon footprints with each band in the footprint representing the corresponding Tn5 mutant. By comparing the transposon footprints from the pools of S. typhimurium Tn5 mutants before and after exposure to desiccation, Tn5 mutants that were not recovered after the selection were rapidly identified that would be easily isolated for further genetic analysis.
OPTIMAL PURIFICATION AND SENSITIVE QUANTIFICATION OF DNA FROM FECAL SAMPLES
Authors: JENSEN A.N. , HOORFAR J.
Published: May 2007

Application of reliable, rapid and sensitive methods to laboratory diagnosis of zoonotic infections continues to challenge microbiological laboratories. The recovery of DNA from a swine fecal sample and a bacterial culture extracted by a conventional phenol‐chloroform extraction method was compared to a rapid silica‐membrane spin‐column method (DNeasy Tissue or QIAamp Stool Kit, QIAGEN GmbH). The two spin column methods yielded 3.5 and 2.7 μg of DNA, respectively, when the elution volume was 200 μL, compared to 1.3 and 1.5 μg of DNA, respectively, with the phenol‐chloroform method.

In addition, the detection range of λ‐DNA of a spectrophotometric and a fluorometric (PicoGreen) method was compared. The PicoGreen showed a quantification limit of 1 ng/mL, consistent triplicate measurements, and finally a linear relationship between the concentrations of DNA standards and the fluorescence readings (R2= 0.99 and R2= 1.00).

In conclusion, silica‐membrane columns can provide a more convenient and less hazardous alternative to the conventional phenol‐based method. The results have implication for further improvement of sensitive amplification methods for laboratory diagnosis.
RAPID TEST FOR DIAGNOSIS OF ENTEROHEMORRHAGIC E. COLI O157:H7 IN HUMAN STOOL SAMPLES
Authors: DING SHI‐FA , ZHAO YI‐XUE , LIU LINDA , HATAMI SHAHIN , LEA PETER
Published: May 2007

A new rapid test platform for the direct detection of E. coli O157:H7 in stool samples of infected patients was compared with the current standard methods. The new test, DIAPRO FAST‐Q®, used biochip ICEflo ®technology that provided results within 20 min. Twenty‐one stool samples from patients infected with E. coli O157:H7 or of unknown status were studied. Using the DIAPRO FAST‐Q® method, within 20 min, we confirmed positive results for the seven known E. coli O157:H7 samples. While the standard culture method gave rise to only four positives in the remaining 14 unknown samples, the DIAPRO FAST‐Q® detected E. coli O157:H7 in eight of these samples, which was confirmed subsequently by broth enrichment culture method.
GENETIC SCREENING FOR IDENTIFICATION OF SALMONELLA TYPHIMURIUM TN5 MUTANTS WITH POTENTIAL HYPERSENSITIVITY TO SHORT‐CHAIN FATTY ACIDS
Authors: KWON Y.M. , KUBENA L.F. , NISBET D.J. , RICKE S.C.
Published: May 2007

This study was conducted to test if transposon footprinting could be used to identify transposon mutants of Salmonella typhimurium with growth defects in a media containing short‐chain fatty acids (SCFA) as the test selective condition. High concentrations of SCFA are one of the characteristic conditions in the animal intestine that has been suggested to play a role in inhibiting colonization by nonindigenous bacterial pathogens. When the mutant pools containing 25 Tn5 mutants/pool were analyzed for transposon footprints before and after selection, a polymerase chain reaction (PCR) product could be identified that was present in an input pool, but not in a corresponding output pool. The results indicate that transposon footprinting can be used for negative screening of genes sensitive to SCFA in the S. typhimurium bacterial genome.
FLUORESCENT DNA BINDING DYE‐BASED APPROACH FOR MEASURING THE GROWTH OF AN ESCHERICHIA COLI LYSINE AUXOTROPH AND QUANTIFYING LYSINE
Authors: CHALOVA V. , WOODWARD C.L. , RICKE S.C.
Published: May 2007

Microbiological assays for determination of bioavailable lysine appear to have many advantages. However, since the developed assay is based on bacterial growth and considerable optical density (OD) is required to detect distinguishable differences in extent of growth, it can be time consuming. The purpose of this study was to explore the fluorescence as an alternative method to measure bacterial growth instead of OD and examine the possibility to shorten the time required for the lysine assay. An assay based on SYTO 9 green fluorescent DNA binding dye (Live/Dead BacLight Protocol, Molecular Probes) was used to stain all bacteria in a population. Additional experiments were carried out to determine the ability of fluorescence based on SYTO 9 to overcome problems associated with high nonbacterial background that contributes to OD. From this study it appears that using fluorescence based on SYTO 9 green fluorescent staining, the E. coli lysine auxotroph growth assay can be completed in 9 h instead of 11 h and has the advantage of improved detection sensitivity. Problems associated with interference by high background nonbacterial OD can be partially resolved by fluorescence.
ENUMERATING 3MTM PETRIFILMTM AEROBIC COUNT PLATES USING THE PETRISCAN® AUTOMATED COLONY COUNTER
Authors: GARRY EILEEN , PESTA MEREDITH , WILLIAMS PATRICK
Published: May 2007

In the food and dairy industries, aerobic plate counts are determined by a time‐consuming and laborious hand‐counting method. The PetriScan ® automated colony counter was developed to improve efficiency in the microbiology laboratory. In this study, colony counts of food, dairy, and milk products plated on 3MTM PetrifilmTM Aerobic Count Plates were compared using both automated and manual count plate methods. For sample variation, 16 different food, dairy, and milk products were used. Samples were prepared and serially diluted using Butterfield's diluent according to approved AOAC methods and APHA's Standard Methods. Plates were inoculated, incubated, and counted according to AOAC methods. For data collection, plates with counts between 5 and 300 colonies were included. A total of 55 low (5–30), 29 medium (31–100), and 23 high (101–300) count plates were used. Duplicate results were recorded for both methods; hand counts were tallied by two scientists. The duplicates of the mean log values for manual counts varied by 0.0005 and 0.0007, and the duplicates for the automated counts varied by 0.0011. The mean log value difference between the automated and manual counts for pooled data was 0.035. The correlation coefficient for the regression line comparing the automated and manual count methods for pooled data was 0.98. The regression equation was y = 0.9257x + 0.0781. These results demonstrate that the PetriScan® automated colony counter is a comparable and practical alternative to the standard method of manually counting plates.
AROMA INTENSITIES OF VARIOUS WOOD SMOKE FRACTIONS
Authors: MAGA JOSEPH A. , FAPOJUWO OMOLOLU O.
Published: May 2007

Subjective aroma intensities were performed on smokes generated from cherry, chestnut, hard maple, white and red oak, apple, hickory and mes‐quite woods. The smokes were separated into total, carbonyl, neutral, basic and phenolic fractions. A sensory panel rated the carbonyl fraction of all smokes, except mesquite, as having the strongest smoke intensity. The aroma of the basic fraction was next in intensity. In the case of mesquite, the phenolic fraction was the most intense. Contrary to the common belief that the phenolic fraction is the primary contributor to smoke aroma in wood smoke, this study showed the carbonyl fraction to be the primary contributor for most woods. Because of the potential health danger associated with smoke‐associated phenolic compounds, this study demonstrated that it would be possible to reduce or eliminate the phenolic fraction in many smoke sources without losing smoke aroma intensity.
DEVELOPMENT OF A TEXTURE PROFILE PANEL FOR EVALUATING RESTRUCTURED BEEF STEAKS VARYING IN MEAT PARTICLE SIZE
Authors: BERRY B. W. , CIVILLE G. V.
Published: May 2007

A texture profile panel was developed for measuring textural properties of restructured beef steaks differing in meat particle size. For steaks of different particle sizes, considerable differences existed in the type of sample breakdown and shape of chewed pieces after just two chews. Panelists also found restructured steaks made from large meat particle sizes to be visually more distorted and to contain more gristle than steaks made from small meat particle sizes. Several characteristics (chunkiness after two chews, coarseness of chewed mass at 15 chews) were dropped from the profile over time, while several characteristics (type of sample breakdown and shape of chewed pieces at two chews, size of chewed pieces at 10 chews) not used initially, were added. The texture profile panel approach appears suitable for discerning the textural differences in restructured steaks that can arise from using different meat particle sizes during processing.
DEVELOPMENT AND APPLICATION OF TEXTURE REFERENCE SCALES
Authors: MUÑOZ ALEJANDRA M.
Published: May 2007

Standard texture rating scales of hardness, adhesiveness, fracturability, cohesiveness, and denseness were modified during the training of a Texture Profile panel. New reference materials were selected for each scale to better illustrate the texture characteristics and intensities and to account for previously recommended food products no longer available. In addition, new reference scales for wetness, adhesiveness to lips, roughness, self‐adhesiveness, springiness, cohesiveness of mass, moisture absorption, adhesiveness to teeth, and manual adhesiveness were developed. The application of new texture reference scales reduced the variability among panelists and provided consistent judgments in texture evaluations. Expanded and improved definitions and evaluation procedures for texture attributes are presented. Also, special considerations for the use of reference scales in texture evaluations are discussed.
COMPARISON OF RATING SCALES: SENSITIVITY, REPLICATES AND RELATIVE MEASUREMENT
Authors: LAWLESS HARRY T. , MALONE GILBERT J.
Published: May 2007

The relative sensitivities of four scaling methods were assessed in central location tests with untrained judges. The scales included category scales, line scales, magnitude estimation, and a hybrid of the line and category scales. Approximate parity was observed among category scales, line scales and the hybrid scale in their ability to differentiate small physical differences. Magnitude estimation was used as efficiently as the other methods by a college population, but less efficiently by a heterogeneous sample of consumers. Judges used the scales with greater accuracy as they became familiar with the range of products to be judged. In spite of relatively small physical differences, subjects used wide ranges of the scales, supporting the view that rating scales are relative, not absolute, measuring instruments.
INTEGRATED COMPUTERIZED SENSORY ANALYSIS
Authors: FINDLAY CHRISTOPHER J. , GULLETT ELIZABETH A. , GENNER DON
Published: May 2007

A computerized sensory analysis system, based on an IBM‐PC compatible local area network, was developed. Panelist input was simplified through the use of a light pen and interactive questionnaire program. The system was integrated to allow preparation of descriptive, hedonic, triangle, structured and unstructured ballots; registration of panelists; collection of data; statistical analysis and report generation. The primary benefits are the simplicity of response for panelists, flexibility for the sensory analyst to design questionnaires and the elimination of time‐consuming manual scoring and data manipulation involved in conventional sensory analysis.
ILLUSTRATIVE EXAMPLES OF PRINCIPAL COMPONENTS ANALYSIS
Authors: FEDERER W.T. , MCCULLOCH C.E. , MILES‐MCDERMOTT N.J.
Published: May 2007

In order to provide a deeper understanding of the workings of principal components, four data sets were constructed by taking linear combinations of values of two uncorrelated variables to form the X‐variates for the principal component analysis. These examples are believed useful for aiding researchers in the interpretation of data and they highlight some of the properties and limitations of principal components analyses.
AVOIDING THE CENTERING BIAS OR RANGE EFFECT WHEN DETERMINING AN OPTIMUM LEVEL OF SWEETNESS IN LEMONADE1
Authors: JOHNSON JILL. , VICKERS ZATA.
Published: May 2007

When two or more levels of an ingredient are presented for evaluation of an ideal level of that ingredient, the centering bias is introduced and the true optimum level is unlikely to be determined. Poulton (1979) and McBride (1982) have suggested methods for avoiding the centering bias, but their methods have never been tested. The purpose of this study was to check the validity of their methods.

Three different ranges of sucrose concentrations were used to determine the optimum level of sucrose in lemonade. Twenty different judges were assigned to each of the three ranges and rated the samples on a just right scale. The unbiased just right sucrose concentrations, determined by the methods suggested by Poulton (1979) and McBride (1982), were 6.7% and 6.9%, respectively. A single stimulus presentation confirmed the results as being an unbiased optimum concentration.
SENSORY MEASUREMENT OF FOOD TEXTURE BY FREE‐CHOICE PROFILING
Authors: MARSHALL RICHARD J. , KIRBY SIMON P. J.
Published: May 2007

Panelists were trained to measure texture of processed cheese analogues of known composition by free‐choice profiling. Panel scores were analyzed by generalized Procrustes (a multivariate method). Plots of the Procrustes scores for the first 2 principal component axes from analysis of separate replicates reflected the experimental design. To compare replicates, scores from Procrustes analysis of the original data were subjected to Procrustes analysis. The results showed that panelists’ assessment of replicates was consistent. Regression of the scores from this second Procrustes analysis showed that they were well explained by the linear effects of either moisture in nonfat solids or fat content. Panelists who performed differently from the rest could be identified. Panelists were more sensitive to changes in moisture in nonfat solids content than fat. It was concluded that the sensory texture of the cheese analogues could be measured satisfactorily by free‐choice profiling.
RELATION OF SENSORY SOURNESS TO CHEMICALLY ANALYZED ACIDITY IN WHOLEMEAL SOUR RYE BREAD
Authors: HELLEMANN ULLA. , POWERS JOHN J. , SALOVAARA HANNU. , SHINHOLSER KATHLEEN. , ELLILÄ MERJA.
Published: May 2007

Sour rye breads containing varying acetic or lactic acid concentrations were used as samples in Experiment 1. Assessors (N=18) could detect difference between 0 to 2 g of added acetic acid (p< 0.02, triangle test), whereas difference between lactic acid concentrations at the same level was detected at p < 0.001. In Experiment 2 five commercial rye breads were profiled by 14 assessors on a 10‐cm graphical scale using 12 flavor descriptors, including desirability. Chemical determinations of pH, titratable acidity, acetic and lactic acid and NaCl concentration were made. Acetic and lactic acid concentrations were strongly related to perceived sourness of odor and taste. The effect of lactic acid on pH and titrable acidity was more pronounced than that of lactic acid. Stepwise discriminant analysis of the sensory data resulted in a 57.1% success rate in discriminating among the samples (nine descriptors used), whereas the analysis of the chemical data discriminated among the samples with a 80% success rate, two variables were useful. Combination of the sensory and chemical data led to 83.3% success with twelve variables.
DISSIMILARITIES IN COGNITION OF FLAVOUR TERMS RELATED TO VARIOUS SENSORY LABORATORIES IN A MULTIVARIATE STUDY
Authors: MARTENS M. , RODBOTTEN M. , MARTENS H. , RISVIK E. , RUSSWURM H.
Published: May 2007

A study of dissimilarities in cognitive perception of 20 common flavor terms was carried out by the Sensory Group of Norway. An average cognitive pattern of the flavor terms was revealed from multidimensional scaling (MDS) and cluster analysis (CLU). In general, small but interesting deviations between different sensory laboratories working with various food products were found by a multivariate pattern recognition technique based on principal component analysis (PCA). Suggestions for finding general reference standards for flavor terms are discussed.
MATHEMATICS OF A LADY TASTING TEA REVISITED
Authors: POWERS JOHN J.
Published: May 2007

The British Standards Institution and the International Standards Organization specify that when mixtures of tea and milk are to be evaluated sensorially, the tea should be added to the milk. Four cups of tea prepared by pouring the tea into the cup first (TIF) and four cups prepared by placing the milk in the cup first (MIF) were presented to 155 panelists in the dark. They were instructed to select by taste the four cups containing the MIF tea. The frequency of correct selection was well above the chance level, indicating that the panelists had detected a difference in flavor. The same task was performed by 131 panelists except they evaluated the tea in light. The panelists were not highly trained tea tasters; in fact, most were not regular drinkers of hot tea. Notwithstanding that, their discriminating power was sufficient to resolve the subtle differences which did exist.
PERCEPTION OF TASTE MIXTURES BY EXPERIENCED AND NOVICE ASSESSORS1
Authors: McBRIDE ROBERT L. , FINLAY DAVID C.
Published: May 2007

The total intensity, sweetness, and acidity of sucrose/citric acid mixtures were judged by two types of taste panel: experienced assessors, most of whom had had many years of experience in sensory evaluation; and novice assessors, none of whom had previously taken part in a taste experiment. In other respects the experimental conditions remained almost constant. There was good correspondence between the two panels, particularly for judgments of total intensity, indicating that novice and experienced assessors evaluate taste mixtures in the same way. However, there was also an indication that experience on sensory panels may attenuate taste suppression, the suppression of acidity by sweetness being less pronounced for the experienced panel than for the novice panel. The implications for mixture perception are noted.
THE APPLICATION OF TWO FREE‐CHOICE PROFILE METHODS TO INVESTIGATE THE SENSORY CHARACTERISTICS OF CHOCOLATE
Authors: McEWAN JEAN A. , COLWILL JANET S. , THOMSON DAVID M. H.
Published: May 2007

The concept of free‐choice profiling allows untrained assessors to participate in sensory profiling. However, it is sometimes the case that such individuals are unable to describe what they perceive when the samples are presented in the isolation of the sensory testing booths. This paper reports an experiment to compare the usual free‐choice profile procedure, with a more structured approach based on Kelly's repertory grid method. Generalized Procrustes analysis was used to analyse the data. The sample configurations obtained from both approaches were very similar, as were the interpretations of the main perceptual dimensions.
EVALUATION OF BITTERNESS OF CAFFEINE IN HOT CHOCOLATE DRINK BY CATEGORY, GRAPHIC, AND RATIO SCALING
Authors: PANGBORN ROSE MARIE. , GUINARD JEAN‐XAVIER. , MEISELMAN HERBERT L.
Published: May 2007

Perceived intensity of bitterness of caffeine (0.5 ‐ 1.6 g/100 mL) and of quinine HCI (0.5 ‐ 1.6 g/L) added to hot cocoa gave similar response distributions with concentration by category scales (CS) and magnitude estimation (ME). Using caffeine additives, CS and graphic analogue scales (GS) gave similar bitterness response functions. Parabolic functions provided the best fit between concentration and ratings for CS, GS and ME. The data demonstrated no difference for ME of bitterness intensity between free or fixed moduli. Hedonic responses also were not modified by whether the modulus was free or fixed, however, greater ME values were ascribed to lower concentrations in the series when the reference was 4 g/L than when it was 2 g/L caffeine. CS intensity response distributions were similar between a series with a larger number of low levels versus a series with a larger number of high levels across the same concentration range. The results indicate that ME may be inappropriate for scaling of degree of liking, independent of type of modulus.
LOGARITHMIC TRANSFORMATION OF MAGNITUDE ESTIMATION DATA AND COMPARISONS OF SCALING METHODS
Authors: LAWLESS HARRY T.
Published: May 2007

Recent studies comparing magnitude estimation to other scaling methods have been criticized for failure to submit the data to logarithmic transformation before statistical analysis, a procedure which can improve the ability of magnitude estimation scaling to differentiate among products. Data from one of these studies was available for re‐analysis, which was conducted both with and without logarithmic transformation of magnitude estimation, category scales and line scales. The ability of magnitude estimation to differentiate among products was improved by log transformation, while the other methods were not. Improvements were associated in pan with reductions in positive skew and improved approximation of the normal distribution. In spite of this improvement, magnitude estimation remained slightly inferior to the other methods especially in the hands of an untrained consumer sample.
TRIANGULAR DIFFERENCE TESTING: REFINEMENTS TO SEQUENTIAL SENSITIVITY ANALYSIS FOR PREDICTIONS FOR INDIVIDUAL TRIADS
Authors: VIÉ ANNE. , O'MAHONY MICHAEL.
Published: May 2007

Using a model system of 3mM NaCl and purified water, predictions were made for subjects’ability to discriminate the odd sample in a set of nine triadic tasting sequences associated with the triangle test. With such individual triads rather than triangular testing protocols which involve more than one triad, it was found necessary to modify the regular Sequential Sensitivity Analysis. The modification required a consideration of sensory adaptation effects caused by repeated tasting of the same stimulus in some of the sequences. Further confirmation was also obtained for the order of magnitude of signal strengths of water and NaCl stimuli tasted after water or NaCl prerinses.
FACTORS INFLUENCING THE EFFICIENCY OF INCOMPLETE BLOCK DESIGNS IN SENSORY EVALUATION EXPERIMENTS
Authors: MAYER DAVID G. , MULDER JOHANNES C.
Published: May 2007

The efficiencies of incomplete block designs were investigated by comparing two hundred and twenty eight analyses from eleven trials using hedonic scales with corresponding randomized complete block analyses. Of the ten explanatory factors examined, only the panelist, the product type, the number of samples per session and the average score of the data had an effect on the efficiency of incomplete block designs. The effect of product type was attributed to influences of produce consumed outside the trial, and the effect of the data mean reflected decreased conscientiousness with products the panelists disliked. With three and four samples per session, incomplete block designs were 31 % and 2 % more efficient, respectively, than randomized complete block designs. When five or more samples were tested, the incomplete block designs were markedly less efficient. The practical implications of all these effects on experimental design are discussed.
USE OF THE DISCRIMINANT FUNCTION TO PREDICT THE NUMBER OF CONSUMERS WHO DISCRIMINATE
Authors: SCRIVEN F. M. , PETTY M. F.
Published: May 2007

Three brands of chocolate milk were evaluated for liking, sweetness, creaminess and natural flavor by 48 consumers, using 100mm line scale. The mean sweetness score for one brand was significantly different to the other two and all other attributes were similar. Discriminant analysis on scores from the line scales showed that 63.8% of the evaluations of the least sweet brand (Brand A) were classified by the discriminant function as belonging to the least sweet brand. 19.1% of the scores for Brand B and 17.0% for Brand C were classified as identifying Brand A. A simple count of the number of consumers ranking each brand as least sweet showed that 63.8% chose Brand A, 19.1% Brand B and 17.0% Brand C. This suggests that the discriminant function provides a measure of the proportion of assessors who can tell the difference or, a measure of the degree of confusion between samples.
THE EFFECTIVENESS OF COMMON FOODS FOR REDUCTION OF CAPSAICIN BURN1
Authors: HUTCHINSON SUSAN E. , TRANTOW LESLIE A. , VICKERS ZATA M.
Published: May 2007

Capsaicin burn was induced by a one percent solution of Tabasco TM sauce in spring water. Four foods, rice, water, butter, and pineapple juice, warmed to 35°C, were used to reduce the burn. A no food treatment was used as a control. Subjects recorded perceived burn intensity by placing slash marks on line scales at set time intervals throughout the tests. Burn was significantly reduced while the foods were in the mouth but increased after the foods were expectorated. The decreased burn may be due to the very presence of a food in the mouth.
TEMPORAL ASPECTS OF HEDONIC RESPONSES1
Authors: TAYLOR DENISE E. , PANGBORN ROSE MARIE.
Published: May 2007

Continuous measurement of degree of liking for chocolate milk varying in milkfat (0–36%) showed significant fluctuations over the 80 s test period. For 17 judges, samples with intermediate fat levels received maximum liking 20–30 s after placement in the mouth then declined to neutral (neither like nor dislike). The nonfat sample gave a flat, neutral response across time while the 36% fat sample was initially neutral, reached maximum dislike at approximately 20 s then gradually returned to neutral. For 5 judges, increasing degree of liking was expressed for increasing fat levels. For both groups, maximum and minimum time‐intensity (T‐I) measurements correlated significantly with results from conventional hedonic scaling on a 20‐cm line. Degree of liking was unaffected by swallowing or expectorating samples by either T‐I or scaling. Thus, similar to perceived intensity, hedonic responses are not static, but show systematic changes during tasting, i.e., from the time the sample is placed into the mouth, through expectoration (or swallowing) until a steady (usually neutral) state is reached.
RELATING SENSORY AND CHEMICAL DATA TO UNDERSTAND FLAVOR
Authors: PIGGOTT JOHN R.
Published: May 2007

Flavor cannot be measured directly by instruments, it is an interaction of consumer and product. A gas chromatogram, even with 250 peaks on it, does not say anything about the flavor, only about the volatiles. In some cases a character impact compound might be present, in a second group of products a small number of compounds may be responsible for the majority of the flavor, while a third class contains more complex foods, which have generally been processed in some way. A range of methods has been, more or less, successfully used to try to link composition data to flavor data, including the calculation of odor units, fractionation of chromatographic effluent, “nasal appraisal” of chromatographic effluent, and a range of multivariate statistical procedures. However, defects in understanding of the mechanism of operation of the chemical senses has limited the success which has been achieved.
DEVELOPMENT OF TERMINOLOGY TO DESCRIBE THE HANDFEEL PROPERTIES OF PAPER AND FABRICS
Authors: CIVILLE GAIL VANCE. , DUS CLARE A.
Published: May 2007

Understanding the tactile feel of paper, nonwoven, and woven products requires a valid and reliable sensory evaluation method which discriminates and describes handfeel properties. The Handfeel Spectrum Descriptive Analysis method separates the sensory tactile properties of paper and fabrics into clearly defined characteristics that are based on sound physical properties. The benefit of using a trained descriptive sensory panel is that resulting analytical sensory data allow full documentation of a sample's sensory tactile properties that can be related to consumer responses and instrumental physical tests. This benefit derives from strict protocols for manipulation and the use of precisely defined terms to discriminate and describe the qualitative properties (characteristics) and their relative intensities (strength) in each product. This paper discusses in detail the protocols for (1) sample preparation, presentation, and handling during evaluation, (2) the definition and scale range for each sensory attribute/characteristic and (3) the application of these data to address business and technical situations with consumer products.
TASTE DESCRIPTIVE ANALYSIS: CONCEPT FORMATION, ALIGNMENT AND APPROPRIATENESS
Authors: O'MAHONY M. , ROTHMAN L. , ELLISON T. , SHAW D. , BUTEAU L.
Published: May 2007

The commonly used approach to psychophysical taste descriptive analysis called ‘taste profiling’was assessed to determine whether it produced concept alignment with an agreed set of labels; it did not. After judges had been trained using a concept alignment procedure involving fifty‐nine standards, the procedure was assessed to see whether broadly defined concepts of ‘sweet’, ‘sour’, ‘salty’and ‘bitter’generalized to various stimuli; they did not. It was concluded that the technique is inferior to currently used methods of descriptive analysis.
CONSISTENCY OF MULTIDIMENSIONAL SCALING MODELS DERIVED FROM ODOR SORTING
Authors: LAWLESS HARRY T. , GLATTER SANDY.
Published: May 2007

The odor perceptions of six groups of subjects who varied in their degree of experience and training in odor evaluation were examined using a sorting task. Data were submitted to multidimensional scaling to produce perceptual models. Regardless of training or expertise, models of different subject groups were highly similar as measured by interpoint distance correlations (median r = 0.74). The retest correlation of one group tested twice with no intervening training was 0.85. A two‐dimensional model provided a better fit to the data of fragrance descriptive panelists than to that of other subjects, but the configuration of these trained panelists was qualitatively similar to all other groups. The method of odor sorting as analyzed by multidimensional scaling was relatively unaffected by learning or other cognitive/linguistic influences on odor perception and showed a fair degree of reliability and inter‐group consistency in odor quality perception.
SHELF‐LIFE OF RAW AND COOKED FIBER‐FORMULATED PORK NUGGETS1
Authors: GOETSCH S. J. , CUNNINGHAM F. E. , IV E. CHAMBERS.
Published: May 2007

Pork shoulders were ground and restructured into nuggets with 5% dietary‐fiber (Avicel) and 1% Nad added. Pork nuggets were battered and breaded with commercial coating ingredients. Half of the nuggets was vacuum packaged and frozen, and the other half was deep‐fat fried for 2 min then vacuum packaged and frozen. Microbial analysis showed intermediate counts (103–4) in raw and cooked products for SPC, yeast and mold, VRB, and psychrotrophs. Salmonella counts were negative. Chemical analysis showed raw and cooked nuggets to be similar in composition except for a lower % moisture in the cooked nuggets caused by cooking loss. Oxidative flavor deterioration of raw and cooked, fiber‐formulated pork nuggets held at ‐17.8°C was studied. Thiobarbituric acid values and sensory evaluations showed that oxidation and flavor deterioration occurred faster in the cooked nuggets. Uncooked, fiber‐formulated pork nuggets maintained quality flavor characteristics through 4 months of storage at ‐17.8°C.
COMPARISON OF THREE DESCRIPTIVE ANALYSIS SCALING METHODS FOR THE SENSORY EVALUATION OF NOODLES1
Authors: GALVEZ FLOR CRISANTA F. , RESURRECCION ANNA V. A.
Published: May 2007

Unstructured line scales (ULS), semi‐structured line scales (SLS), and category scales (CS) were compared in evaluating two samples of mungbean starch noodles. Results indicated that panelists discriminated better between noodle samples when ULS were used. When identical sets of descriptors were used, more terms were found to be discriminatory with ULS but a smaller group of descriptors was sufficient to discriminate between samples compared to those needed for SLS or CS. It was also found that the use of ULS was most reliable and most sensitive to product differences. Increased anchoring of the line scales with the intensity standards did not result in increased sensitivity and reliability of the scale. Results also showed that different scaling methods may be used in succession at intervals of at least 4 h by a trained panel in evaluating the sensory characteristics of noodles using descriptive analysis.
THE USE OF FOURIER ANALYSIS TO COMPARE THE SENSORY PROFILES OF PRODUCTS
Authors: PETTY M. F. , SCRIVEN F. M.
Published: May 2007

A consumer panel comprising 60 females evaluated three coffee whiteners and fresh milk for a number of sensory attributes including liking of flavor and appearance, overall liking, natural flavor and odor, creaminess and watery flavor. Fourier analysis was used to produce a plot which readily identified the whiteners with sensory profiles most similar to fresh milk. More importantly, the whitener whose sensory profile was significantly different from that of fresh milk was identified from the Fourier plot, something which could not be done by traditional univariate methods or even by an overall discriminant analysis.
USAGE BEHAVIOR OF MEAT PRODUCTS BY AUSTRALIANS AND HONG KONG CHINESE: A COMPARISON OF FREE CHOICE AND CONSENSUS PROFILING
Authors: SCRIVEN F. M. , MAK Y. L.
Published: May 2007

Australian and Hong Kong Chinese male and female consumers, aged 20 to 30 years, evaluated a range of 16 meat products using two questionnaires. One questionnaire comprised the 12 most frequently used terms by consumers to describe how, when and where they would most often consume each product. The alternate questionnaire for each individual comprised free choice vocabulary. Half of each consumer sample used the consensus questionnaire and the other half, the free choice questionnaire first, and indicated how often they would consume each meat product in the various contexts listed using graphic line scales of 100 mm anchored at either end by the words ‘never’ and ‘always’. After an interval of time, the alternate questionnaire was completed. It was found that similar conclusions can be drawn about major contextual dimensions either by principal component analysis of data from a consensus questionnaire or by generalized Procrustes analysis of data from free choice profiling.
HEDONIC SPREADABILITY OPTIMA OF SELECTED EDIBLE FATS
Authors: ROHM H. , RAABER SUSANNE.
Published: May 2007

A panel of untrained judges was asked to assess spreadability of selected solid edible fat samples (butter, margarine, low fat products) of different temperature with regard to hedonic preferences. Instrumental measurements were performed by cone penetration with constant load. The statistical analysis of the ranked sensory data showed significant spreadability optima in the apparent yield value range of approximately 30–60 kPa. Differences between the selected fats were not observed.
MOST PREFERRED LEVEL OF SUGAR: RAPID MEASURE AND CONSUMPTION TEST
Authors: DAILLANT B. , ISSANCHOU S.
Published: May 2007

This study dealt with the determination of the most preferred level of sugar in plain yoghurt. Twenty‐four consumers participated in 13 lab meals. The results of a rapid test, based on ideal relative‐rating were compared to the results of a consumption test, based on the amount of test product consumed, in order to assess if this rapid test predict actual consumption behavior. Linear regression of the ideal‐relative intensity ratings on logarithms of sucrose concentrations was used to estimate, for each subject, ideal‐point (i.e., sucrose level corresponding to a null distance from ideal) and slope (which accounts for tolerance) with a good reproducibility. The consumption tests revealed behavior which could not be related to the level of sugar for 30% of the subjects. Moreover, the most preferred level of sugar obtained with the rapid test was not always the most consumed. However, the two mean values of ideal level are close: 6.3% with ideal‐relative rating, and 7.5% with measurement of eaten quantity. Thus our experimentation underlines the interest of ideal‐relative rating as a good predictor of consumption behavior.
DETECTION AND INTERPRETATION OF VARIATION WITHIN AND BETWEEN ASSESSORS IN SENSORY PROFILING
Authors: NÆS TORMOD. , SOLHEIM RAGNHILD.
Published: May 2007

In this paper we discuss methods that can be used to evaluate the performance of sensory panels. In particular we concentrate on detection of variation within and among panelists. A systematic presentation of some simple, graphically oriented tools will be given. Interpretation aspects of the tools will be emphasized. The methods will be illustrated by computations from a sensory experiment based on 4 sausage products. The example demonstrates how the tools can be used to evaluate the reproducibility of the assessors and also how they can be used to detect different types of individual differences among the assessors.
EFFECTS OF VISUAL MASKING TECHNIQUES ON THE INTENSITY RATING OF SWEETNESS OF GELATINS AND LEMONADES1
Authors: FLETCHER LEAH. , HEYMANN HILDEGARDE. , ELLERSIECK MARK.
Published: May 2007

Visual masking techniques are frequently used to prevent panelists from discriminating among samples on the basis of color differences, only. The purpose of the study was to determine if these conditions alter the responses of the judges. Raspberry gelatins sweetened with 9, 10, 14 and 16% sucrose, respectively, and lemonades sweetened with 8, 10, 12 and 14% sucrose, respectively, were rated for perceived sweetness intensity using four different visual masking conditions (red lights, red glasses, dyes and blindfolds) and a white light and clear glasses control condition. Most of the visual masking techniques did not significantly affect the sweetness scores for the gelatins or lemonades. The one exception was the dye condition for the lemonades where the color (turquoise) probably affected the results.
SENSORY QUALITY STUDIES ON MANGO AROMA CONCENTRATE DURING STORAGE
Authors: RAMTEKE R.S. , DHANARAJ S. , EIPESON W.E.
Published: May 2007

Aroma concentrates from Alphonso and Totapuri mango pulps were prepared and the aroma stripped pulps were concentrated two folds. Ready to serve beverages were prepared from fresh mango pulps and pulp concentrates by adding different levels of aroma concentrates. Sensory evaluation of beverages showed that in the case of Alphonso mango addition of 50%, 75% and 100% aroma concentrate gave comparable quality while with Totapuri only 50% level showed comparable quality.

The aroma stripped pulp concentrates were canned as such and after mixing with 50% aroma concentrates and stored at 25 × 5°C. Aroma concentrates were bottled and stored at 2°C. At different intervals of storage, beverages were prepared and evaluated. The results showed that throughout the storage period, beverages prepared from mango concentrates to which 50% aroma was added before canning was superior to those prepared from aroma stripped canned pulp concentrates to which aroma was added at the time of preparation of beverage indicating the effect of mango pulp on aroma stability.
PHYSICAL AND SENSORY CHARACTERISTICS OF CAT LITTER1
Authors: CLIFF MARGARET. , HEYMANN HILDEGARDE.
Published: May 2007

Eighteen commercial cat litters were characterized for the following physical characteristics: water holding capacity, drying time, pH, cost, density, residual water, and particle size. Using sensory analysis, eight of the litters were evaluated for dustiness, clumpability and odor control before and after use and storage. The cat litters differed substantially in both physical and sensory properties. The crystal litters were noted for their small uniform size, high water holding capacity and clumpability. The recycled litter was most dusty and ammoniacal; whereas, the granule litter had an innately offensive odor. The alfalfa litter had superior odor control, but neither clumped nor dried well. The clay litters could be differentiated by pH, residual water, water holding capacity and could be classified as either perfumed and nonperfumed. Some of the perfumed litters became intensely perfumed when used and stored; whereas, the other perfumed litters behaved like the nonperfumed litters and became more offensive.