Food Science Commons^™

Chitosan Protects Cooked Ground Beef And Turkey Against Clostridium Perfringens Spores During Chilling, Vijay Juneja, Harshavardhan Thippareddi, Latiful Bari, Yasuhiro Inatsu, Shinichi Kawamoto, Mendel Friedman

Department of Food Science and Technology: Faculty Publications

We investigated the inhibition of Clostridium perfringens spore germination and outgrowth by the biopolymer chitosan during abusive chilling of cooked ground beef (25% fat) and turkey (7% fat) obtained from a retail store. Chitosan was mixed into the thawed beef or turkey at concentrations of 0.5%, 1.0%, 2.0%, or 3.0% (w/w) along with a heat-activated 3-strain spore cocktail to obtain a final spore concentration of 2 to 3 log₁₀ CFU/g. Samples (5 g) of the ground beef or turkey mixtures were then vacuum-packaged and cooked to 60 ◦C in 1 h in a temperature-controlled water bath. Thereafter, the products …

Making Yogurt At Home, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Tangy, nutritious yogurt can be made at home with regular kitchen utensils, and often is less expensive than buying it. This NebGuide describes how.

Treponema Denticola In Disseminating Endodontic Infections, F. Foschi, Jacques Izard, H. Sasaki, V. Sambri, C. Prati, R. Müller, P. Stashenko

Department of Food Science and Technology: Faculty Publications

Treponema denticola is a consensus periodontal pathogen that has recently been associated with endodontic pathology. In this study, the effect of mono-infection of the dental pulp with T. denticola and with polymicrobial “red-complex” organisms (RC) (Porphyromonas gingivalis, Tannerella forsythia, and T. denticola) in inducing disseminating infections in wild-type (WT) and severe-combined-immunodeficiency (SCID) mice was analyzed. After 21 days, a high incidence (5/10) of orofacial abscesses was observed in SCID mice mono-infected with T. denticola, whereas abscesses were rare in SCID mice infected with the red-complex organisms or in wild-type mice. Splenomegaly was …

Secretion Of Food Allergen Proteins In Saliva, S. J. Maleki, H. Cheng, B. Perelman, S. Hefle, P. Vadas

Department of Food Science and Technology: Faculty Publications

RATIONALE: Peanut proteins were found to be secreted in 50% of lactating women’s breast milk. We wanted to develop a testing method to predict the secretion of peanut protein in breast milk. The secretion of food protein in saliva was hypothesized to be a possible predictor of secretion of foods in breast milk following ingestion.

METHODS: Non-allergic volunteers, some lactating, ingested 50 grams of either whole peanuts, peanut milk or cow’s milk and various immunoassays were utilized to analyze for the presence of peanut or cow’s milk proteins in saliva and breast milk. Saliva and breast milk samples were subjected …

Prebiotic Galactooligosaccharides Reduce Adherence Of Enteropathogenic Escherichia Coli To Tissue Culture Cells, Kari Shoaf, George L. Mulvey, Glen D. Armstrong, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Prebiotic oligosaccharides are thought to provide beneficial effects in the gastrointestinal tract of humans and animals by stimulating growth of selected members of the intestinal microflora. Another means by which prebiotic oligosaccharides may confer health benefits is via their antiadhesive activity. Specifically, these oligosaccharides may directly inhibit infections by enteric pathogens due to their ability to act as structural mimics of the pathogen binding sites that coat the surface of gastrointestinal epithelial cells. In this study, the ability of commercial prebiotics to inhibit attachment of microcolony-forming enteropathogenic Escherichia coli (EPEC) was investigated. The adherence of EPEC strain E2348/69 on HEp-2 …

Practical And Predictive Bioinformatics Methods For The Identification Of Potentially Cross-Reactive Protein Matches, Richard E. Goodman

Department of Food Science and Technology: Faculty Publications

A bioinformatics comparison of proteins introduced into food crops through genetic engineering provides a mechanism to identify those proteins that may present an increased risk of allergic reactions for individuals with existing allergies. The goal is to identify proteins that are known to be allergens or are so similar to an allergen that they may induce allergic cross-reactions. Three comparative approaches have traditionally been used, or considered for safety evaluations. One identifies any short (6–8) amino acid segment of the protein that exactly matches a known allergen sequence. The second is an overall primary sequence comparison using Basic Local Alignment …

Modulation Of The Coma-Dependent Quorum Response In Bacillus Subtilis By Multiple Rap Proteins And Phr Peptides, Jennifer M. Auchtung, Catherine A. Lee, Alan D. Grossman

Department of Food Science and Technology: Faculty Publications

In Bacillus subtilis, extracellular peptide signaling regulates several biological processes. Secreted Phr signaling peptides are imported into the cell and act intracellularly to antagonize the activity of regulators known as Rap proteins. B. subtilis encodes several Rap proteins and Phr peptides, and the processes regulated by many of these Rap proteins and Phr peptides are unknown. We used DNA microarrays to characterize the roles that several rap-phr signaling modules play in regulating gene expression. We found that rapK-phrK regulates the expression of a number of genes activated by the response regulator ComA. ComA activates expression of genes involved in …

Paired-End Sequence Mapping Detects Extensive Genomic Rearrangement And Translocation During Divergence Of Francisella Tularensis Subsp. Tularensis And Francisella Tularensis Subsp. Holarctica Populations, Michael P. Dempsey, Joseph Nietfeldt, Jaques Ravel, Steven H. Hinrichs, Robert Crawford, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

Comparative genome hybridization of the Francisella tularensis subsp. tularensis and F. tularensis subsp. holarctica populations have shown that genome content is highly conserved, with relatively few genes in the F. tularensis subsp. tularensis genome being absent in other F. tularensis subspecies. To determine if organization of the genome differs between global populations of F. tularensis subsp. tularensis and F. tularensis subsp. holarctica, we have used paired-end sequence mapping (PESM) to identify regions of the genome where synteny is broken. The PESM approach compares the physical distances between paired-end sequencing reads of a library of a wild-type reference F. tularensis …

Tannerella Forsythia, A Periodontal Pathogen Entering The Genomic Era, Anne C. R. Tanner, Jacques Izard

Department of Food Science and Technology: Faculty Publications

Several questions need to be addressed to evaluate whether Tannerella forsythia is to be considered a periodontal pathogen. T. forsythia has been detected in periodontal health and disease, so could it be a pathogen? The species was not detected in many studies despite finding other putative pathogens, so could it be important in pathogenicity? The challenges of working with T. forsythia include its fastidious and anaerobic growth requirements for cultural detection. Thus, studies associating T. forsythia with periodontal and other oral infections have used noncultural approaches (immunoassays and DNA-based assays) in addition to cultural approaches. We feel …

Gelatinization And Solubility Of Corn Starch During Heating In Excess Water: New Insights, Wajira S. Ratnayake, David S. Jackson

Department of Food Science and Technology: Faculty Publications

Starch gelatinization is associated with the disruption of granular structure causing starch molecules to disperse in water. This study was designed to examine starch granules as they were heated in water, and their resulting morphological, structural, and solubility traits. The results indicate that starch gelatinization is a more complex process than the previously suggested order-to-disorder transition. The energy absorbed by the granules facilitates the rearrangement or formation of new bonds among molecules prior to the temperatures normally associated with the melting of amylopectin crystallites during gelatinization. It is also evident that amylose plays an important role during the initial stages …

Grain Quality Of Brazilian Maize Genotypes As Influenced By Nitrogen Level, Aildson P. Duarte, Stephen C. Mason, David S. Jackson, Jorge De C. Kiehl

Department of Food Science and Technology: Faculty Publications

Maize (Zea mays L.) is an important crop in Brazil, and concerns about grain quality are increasingly important with increasing exports and use of grain for specific end-uses. A wide range of genotypes are grown and N application is required to produce high yields. The objectives of these studies were to: (i) determine N application effects on the kernel hardness and breakage susceptibility of a wide range of Brazilian genotypes ranging from dent to flint kernel types and (ii) determine relationships among kernel hardness and breakage susceptibility tests, yield and N and oil concentration. Three studies were conducted with …

Is The Low Prevalence Of Peanut Allergy In Israel Due To Hypoallergenic Peanut Products?, S. J. Maleki, S. L. Hefle, H. Cheng, Y. Katz, G. Du Toit, G. Lack

Department of Food Science and Technology: Faculty Publications

RATIONALE: In Israel the majority of infants less than 12 months old regularly consume peanut products in contrast to the UK where infants avoid peanut products. Previous studies suggest a low prevalence of peanut allergy in Israel and raise the possibility that the processing of Israeli peanut snacks renders them hypoallergenic. Therefore, the allergen content and allergenicity of the most popular peanut products consumed by children and infants in the UK and Israel were compared to determine if such differences could explain the variation in the prevalence of peanut allergy.

METHODS: The total protein content of whole snack products was …

Functionality Behavior Of Raw And Extruded Corn Starch Mixtures, Serap Ozcan, David S. Jackson

Department of Food Science and Technology: Faculty Publications

Relationships between the structural properties of raw. and extruded com starches and their functionalities were investigated using mixtures of these starch types. Extruded starch had higher water absorption and water solubility indices, and produced lower RVA viscosity profiles when compared with raw starch. It also had no differential scanning calorimetry (DSC) endotherm. Gel cohesiveness and adhesiveness of both starch types were similar, while extruded starch gels were softer. Extruded starch produced lower Rapid Visco Analyser (RVA) viscosity profiles than raw starch due to starch degradation during extrusion. The raw and extruded starch components bad negative interaction coefficients, thus RVA viscosity …

Development Of Laboratory Techniques To Mimic Industrial-Scale Nixtamalization, Roxana Yglesias, Anne M. Parkhurst, David S. Jackson

Department of Food Science and Technology: Faculty Publications

A laboratory nixtamalization process was developed to imitate larger scale cooking/steeping conditions. Corn (45 kg) was cooked in a pilot plant gas-fired cook/steep tank and temperature was monitored every 30 sec. Cooling and heating rates were mimicked in the laboratory using a digital temperature programmable hot plate that adjusted grain-waterlime temperature changes at a specified rate. A Response Surface Central Composite Design was used to model pasting and thermal properties of nixtamal and masa as a function of cooking temperature (86-96°C), cooking time (20-40 min), and steeping time (3-11.77 hr). Nixtamal and masa moisture. dry matter loss, nixtamal and masa …

Ctla-4 Signaling Regulates The Intensity Of Hypersensitivity Responses To Food Antigens, But Is Not Decisive In The Induction Of Sensitization, Femke Van Wijk, Sanne Hoeks, Stefan Nierkens, Stef J. Koppelman, Peter Van Kooten, Louis Boon, Leon M.J. Knippels, Raymond Pieters

Department of Food Science and Technology: Faculty Publications

Although food allergy has emerged as a major health problem, the mechanisms that are decisive in the development of sensitization to dietary Ag remain largely unknown. CTLA-4 signaling negatively regulates immune activation, and may play a crucial role in preventing induction and/or progression of sensitization to food Ag. To elucidate the role of CTLA-4 signaling in responses to food allergens, a murine model of peanut allergy was used. During oral exposure to peanut protein extract (PPE) together with the mucosal adjuvant cholera toxin (CT), which induces peanut allergy, CTLA-4 ligation was prevented using a CTLA-4 mAb. Additionally, the effect of …

Etiology Of Oral Disease In View Of Microbial Complexity, Anne C. R. Tanner, Jacques Izard

Department of Food Science and Technology: Faculty Publications

The number of different microorganisms recognized in the oral cavity using molecular methods has more than doubled compared with the number isolated using cultural techniques. This finding necessitates a reevaluation of which species may be pathogens in dental infections. Molecular methods used to determine microbial diversity include broad range target Polymerase Chain Reaction with ‘universal primers,’ and cloning amplicons or denaturing gradient gel electrophoresis to separate DNA fragments before sequencing. These molecular methods have clarified and expanded the taxonomy of oral microbial species. Discrepancies between comprehensive molecular and cultural methods suggest that neither method alone can adequately evaluate associations of …

Functional Consequences Of Genome Evolution In Listeria Monocytogenes: The Lmo0423 And Lmo0422 Genes Encode ΣC And Lstr, A Lineage Ii-Specific Heat Shock System, Chaomei Zhang, Joseph Nietfeldt, Min Zhang, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

Listeria monocytogenes strains belonging to phylogenetic lineage II (serotypes 1/2a, 1/2c, and 3a) carry a lineage-specific genome segment encoding a putative sigma subunit of RNA polymerase (lmo0423, herein referred to as sigC), a gene of unknown function (lmo0422) similar to the padR family of regulators, and a gene that is similar to the rodA-ftsW family of cell wall morphology genes (lmo0421). To understand the function of this set of genes, their expression patterns and the effects of null mutations in the lineage II L. monocytogenes strain 10403S were examined. The data are consistent with the three genes comprising an …

Periplasm Organization In Treponema Denticola As Studied By Cryo-Electron Tomography, Jacques Izard, C.-E. Hsieh, C. A. Mannella, Ronald J. Limberger, M. Marko

Department of Food Science and Technology: Faculty Publications

As a spirochete, the genus Treponema is one of the few major bacterial groups whose natural phylogenic relationships are evident at the level of gross phenotypic characteristics such as their morphology. Treponema spp. are highly invasive due to their unique motility in dense media, and their ability to penetrate cell layers. This feature is associated with the helical cell body and the presence of flagellar filaments in the periplasm. Treponema denticola is an oral pathogen involved in endodontic infections and periodontal diseases. The presence and quantity of T. denticola in the subgingival biofilm is correlated with the severity of periodontal …

Evaluation Of Liquid Nitrogen Freeze Drying And Ethanol Dehydration As Methods To Preserve Partially Cooked Starch And Masa Systems, Roxana Yglesias, David S. Jackson

Department of Food Science and Technology: Faculty Publications

Preservation of starch structure/properties. including structures formed during partial or complete cooking, are important when the impact of processing conditions is being studied. Two preservation techniques used to study changes in starch during thermal-mechanical processing are commonly cited in the literature: 1) rapid freezing followed by lyophilization, and 2) a dehydration procedure using alcohols. A comparative determination on how these methods affect various starch structures has not been widely reported. Corn starch samples were collected from the Rapid Visco-Analyser (RVA) at 3 min (swollen granules, 30°C), at the top of the pasting peak (gelatinized granules, 95°C), at the bottom of …

Measurements Of Fitness And Competition In Commensal Escherichia Coli And E. Coli O157:H7 Strains, Lisa M. Durso, David R. Smith, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Although the main reservoirs for pathogenic Escherichia coli O157:H7 are cattle and the cattle environment, factors that affect its tenure in the bovine host and its survival outside humans and cattle have not been well studied. It is also not understood what physiological properties, if any, distinguish these pathogens from commensal counterparts that live as normal members of the human and bovine gastrointestinal tracts. To address these questions, individual and competitive fitness experiments, indirect antagonism assays, and antibiotic resistance and carbon utilization analyses were conducted using a strain set consisting of 122 commensal and pathogenic strains. The individual fitness experiments, …

Development Of A Novel Chloramphenicol Resistance Expression Plasmid Used For Genetic Complementation Of A Flig Deletion Mutant In Treponema Denticola, Linda L. Slivienski-Gebhardt, Jacques Izard, William A. Samsonoff, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

A new expression plasmid containing the fla operon promoter and a staphylococcal chloramphenicol resistance gene, was constructed to help assess the role of fliG in Treponema denticola motility. Deletion of fliG resulted in a nonmotile mutant with a markedly decreased number of flagellar filaments. Wild-type fliG genes from T. denticola and from Treponema pallidum were cloned into this expression plasmid. In both cases, the gene restored the ability of the mutant to gyrate its cell ends and enabled colony spreading in agarose. This shuttle plasmid enables high-level expression of genes in T. denticola and possesses an efficient selectable …

Dna Sequence Analysis Of Regions Surrounding BlaCmy-2 From Multiple Salmonella Plasmid Backbones, W.P. Giles, Andrew K. Benson, M.E. Olson, Robert W. Hutkins, J.M. Whichard, P.L. Winokur, P.D. Fey

Department of Food Science and Technology: Faculty Publications

The emergence in the United States of resistance to expanded-spectrum cephalosporin (e.g., ceftriaxone) within the salmonellae has been associated primarily with three large (>100-kb) plasmids (designated types A, B, and C) and one 10.1-kb plasmid (type D) that carry the bla_CMY-2 gene. In the present study, the distribution of these four known bla_CMY-2-carrying plasmids among 35 ceftriaxone-resistant Salmonella isolates obtained from 1998 to 2001 was examined. Twenty-three of these isolates were Salmonella enterica serotype Newport, 10 were Salmonella enterica serotype Typhimurium, 1 was Salmonella enterica serotype Agona, and 1 was Salmonella enterica serotype Reading. All 23 …

Regulation Of Transcription Of Compatible Solute Transporters By The General Stress Sigma Factor, ΣB, In Listeria Monocytogenes, Mehmet Sevket Cetin, Chaomei Zhang, Robert W. Hutkins, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

Listeria monocytogenes is well known for its durable physiological characteristics, which allow the organism to grow at low temperature and pH and high osmolarity. Growth under high osmolarity depends on the accumulation of compatible solutes, among which glycine betaine and carnitine are the preferred solutes for this organism. Three different transport systems, Gbu, BetL, and OpuC, have been identified in L. monocytogenes which serve to scavenge the preferred compatible solutes. The general stress response regulator σ^B has been shown to play an important role in osmotic adaptation in L. monocytogenes, presumably by directing transcription from one or more …

Regulation Of Transcription Of Compatible Solute Transporters By The General Stress Sigma Factor, ΣB, In Listeria Monocytogenes, Mehmet Sevket Cetin, Chaomei Zhang, Robert W. Hutkins, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

Listeria monocytogenes is well known for its durable physiological characteristics, which allow the organism to grow at low temperature and pH and high osmolarity. Growth under high osmolarity depends on the accumulation of compatible solutes, among which glycine betaine and carnitine are the preferred solutes for this organism. Three different transport systems, Gbu, BetL, and OpuC, have been identified in L. monocytogenes which serve to scavenge the preferred compatible solutes. The general stress response regulator σ^B has been shown to play an important role in osmotic adaptation in L. monocytogenes, presumably by directing transcription from one or more …

Method For Mulching An Agricultural Soil Bed Using A Biodegradable Protein Material And A Mulched Agricultural Crop Growing Plot Produced Thereby, Yusuf Ali, Viswas Ghorpade, Robert Weber, Milford Hanna

Department of Food Science and Technology: Faculty Publications

A method is provided for mulching an agricultural Soil bed using a biodegradable protein mulch material. The method includes the preparation of a film forming Solution of a film forming protein material. The film forming protein Solution is then sprayed directly onto a Surface of an agricultural Soil bed. The solution dries to form a thin film of protein material on the Surface of the agricultural Soil bed. The protein material may comprise a plant protein, a milk protein, an animal protein, a whey protein, casein, an egg protein or gelatin. Following a harvest, the mulch material, which is biodegradable, …

Catabolite Repression And Virulence Gene Expression In Listeria Monocytogenes, Stefanie Evans Gilbreth, Andrew K. Benson, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Previous studies have suggested that carbohydrates may affect expression of virulence genes in Listeria monocytogenes. Which carbohydrates influence virulence gene expression and how carbohydrates mediate expression, however, is not clear. The goal of this work was to examine how carbohydrates affect virulence gene expression in L. monocytogenes 10403S. Growth studies were conducted in medium containing glucose and various sugars. Metabolism of arbutin, arabitol, cellobiose, mannose, maltose, trehalose, and salicin were repressed in the presence of glucose. Only when glucose was consumed were these sugars fermented, indicating that catabolite repression by glucose had occurred. To determine whether virulence gene expression …

A Consensus Protocol For The Determination Of The Threshold Doses For Allergenic Foods: How Much Is Too Much?, S. L. Taylor, S. L. Hefle, C. Bindslev-Jensen, F. M. Atkins, C. Andre, C. Bruijnzeel-Koomen, A. W. Burks, R. K. Bush, M. Ebisawa, P. A. Eigenmann, A. Host, Jonathan O. B. Hourihane, E. Isolauri, D. J. Hill, A. Knulst, G. Lack, H. A. Sampson, D. A. Moneret-Vautrin, F. Rance, P. A. Vadas, J. W. Yunginger, R. S. Zeiger, J. W. Salminen, C. Madsen, P. Abbott

Department of Food Science and Technology: Faculty Publications

Background:While the ingestion of small amounts of an offending food can elicit adverse reactions in individuals with IgE-mediated food allergies, little information is known regarding these threshold doses for specific allergenic foods. While low-dose challenge trials have been conducted on an appreciable number of allergic individuals, a variety of different clinical protocols were used making the estimation of the threshold dose very difficult.

Objective: A roundtable conference was convened to develop a consensus clinical protocol for low-dose challenge trials for the estimation of threshold doses for specific allergenic foods.

Methods: In May 2002, 20 clinical allergists and other interested parties …

Presentation Of Allergen In Different Food Preparations Affects The Nature Of The Allergic Reaction: A Case Series, K. E. C. Grimshaw, R. M. King, Julie A. Nordlee, S. L. Hefle, John O. Warner, J. O.'B. Hourihane

Department of Food Science and Technology: Faculty Publications

Background: Characterization of fatal and nonfatal reactions to food indicates that the majority of reactions are due to the ingestion of prepared foods rather than the nonprocessed allergen. In an ongoing study that used a double-blind placebo-controlled food challenge to investigate peanut allergy and clinical symptoms, the observed reaction severity in four of the first six subjects was greater than anticipated. We hypothesized that this was due to differences in the composition of the challenge vehicle.

Objective: The aim was to investigate whether the severity of observed challenge reactions would be repeated on rechallenge with a lower fat …

Tomographic Reconstruction Of Treponemal Cytoplasmic Filaments Reveals Novel Bridging And Anchoring Components, Jacques Izard, Bruce F. Mcewen, Rita M. Barnard, Thomas Portuese, William A. Samsonoff, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

An understanding of the involvement of bacterial cytoplasmic filaments in cell division requires the elucidation of the structural organization of those filamentous structures. Treponemal cytoplasmic filaments are composed of one protein, CfpA, and have been demonstrated to be involved in cell division. In this study, we used electron tomography to show that the filaments are part of a complex with a novel molecular organization that includes at least two distinct features decorating the filaments. One set of components appears to anchor the filaments to the cytoplasmic membrane. The other set of components appears to bridge the cytoplasmic filaments on the …

Functional And Comparative Genomic Analyses Of An Operon Involved In Fructooligosaccharide Utilization By Lactobacillus Acidophilus, Rodolphe Barrangou, Eric Altermann, Robert W. Hutkins, Raul Cano, Todd Klaenhammer

Department of Food Science and Technology: Faculty Publications

Lactobacillus acidophilus is a probiotic organism that displays the ability to use prebiotic compounds such as fructooligosaccharides (FOS), which stimulate the growth of beneficial commensals in the gastrointestinal tract. However, little is known about the mechanisms and genes involved in FOS utilization by Lactobacillus species. Analysis of the L. acidophilus NCFM genome revealed an msm locus composed of a transcriptional regulator of the LacI family, a four-component ATP-binding cassette (ABC) transport system, a fructosidase, and a sucrose phosphorylase. Transcriptional analysis of this operon demonstrated that gene expression was induced by sucrose and FOS but not by glucose or fructose, suggesting …