Food Science Commons^™

Metabolism Of Fructooligosaccharides By Lactobacillus Paracasei 1195, Handan Kaplan, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Fermentation of fructooligosaccharides (FOS) and other oligosaccharides has been suggested to be an important property for the selection of bacterial strains used as probiotics. However, little information is available on FOS transport and metabolism by lactic acid bacteria and other probiotic bacteria. The objectives of this research were to identify and characterize the FOS transport system of Lactobacillus paracasei 1195. Radiolabeled FOS was synthesized enzymatically from [³H]sucrose and purified by column and thin-layer chromatography, yielding three main products: glucose (G) α-1,2 linked to two, three, or four fructose (F) units (GF₂, GF₃, and GF …

A Response Surface Analysis Of Commercial Corn Starch Annealing, Serap Ozcan, David S. Jackson

Department of Food Science and Technology: Faculty Publications

Native starch is composed of granules that are organized, durable, and morphologically identifiable microscopic structures of amylose and amylopectin molecules (Virtanen and Autio 1993; Snyder 1984). Sahai and Jackson (1994) reported that native starch granules from a single starch source were not homogeneous in character and had different functional properties. Because of their heterogeneity, it should not be expected that starch granules behave uniformly when heated in water (Sahai and Jackson 1996). The extent of heat treatment, starch hydration. and the inherent physical and chemical properties of native starch determine the structure and functionality of starch in a food system. …

The Safety Of Genetically Modified Foods Produced Through Biotechnology, Robert M. Hollingworth, Leonard F. Bjeldanes, Michael Bolger, Ian Kimber, Barbara Jean Meade, Steve L. Taylor, Kendall B. Wallace

Department of Food Science and Technology: Faculty Publications

The Society of Toxicology (SOT) is committed to protecting and enhancing human, animal, and environmental health through the sound application of the fundamental principles of the science of toxicology. It is with this goal in mind that the SOT defines here its current consensus position on the safety of foods produced through biotechnology (genetic engineering). These products are commonly termed genetically modified foods, but this is misleading, since conventional methods of microbial, crop, and animal improvement also produce genetic modifications and these are not addressed here.
The available scientific evidence indicates that the potential adverse health effects arising from biotechnology-derived …

Characterization Of Escherichia Coli O157:H7 From Downer And Healthy Dairy Cattle In The Upper Midwest Region Of The United States, C. M. Byrne, I. Erol, J. E. Call, C. W. Kaspar, D. R. Buege, C. J. Hiemke, P. J. Fedorka-Cray, Andrew K. Benson, F. M. Wallace, J. B. Luchansky

Department of Food Science and Technology: Faculty Publications

While cattle in general have been identified as a reservoir of Escherichia coli O157:H7, there are limited data regarding the prevalence and clonality of this pathogen in downer dairy cattle and the potential impact to human health that may occur following consumption of meat derived from downer dairy cattle. In the present study, conducted at two slaughter facilities in Wisconsin between May and October of 2001, we established a higher prevalence of E. coli O157:H7 in fecal and/or tissue samples obtained aseptically from intact colons of downer dairy cattle (10 of 203, 4.9%) than in those from healthy dairy cattle …

Genome Diversification In Phylogenetic Lineages I And Ii Of Listeria Monocytogenes: Identification Of Segments Unique To Lineage Ii Populations, Chaomei Zhang, Min Zhang, Jingliang Ju, Joseph Nietfeldt, John Wise, Phillip M. Terry, Michael Olson, Stephen D. Kachman, Martin Wiedmann, Mansour Samadpour, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

Thirteen different serotypes of Listeria monocytogenes can be distinguished on the basis of variation in somatic and flagellar antigens. Although the known virulence genes are present in all serotypes, greater than 90% of human cases of listeriosis are caused by serotypes 1/2a, 1/2b, and 4b and nearly all outbreaks of food-borne listeriosis have been caused by serotype 4b strains. Phylogenetic analysis of these three common clinical serotypes places them into two different lineages, with serotypes 1/2b and 4b belonging to lineage I and 1/2a belonging to lineage II. To begin examining evolution of the genome in these serotypes, DNA microarray …

Wheat Tortilla Quality: Impact Of Amylose Content Adjustments Using Waxy Wheat Flour, G. Guo, David S. Jackson, Robert A. Graybosch, Anne M. Parkhurst

Department of Food Science and Technology: Faculty Publications

Amylose content is closely related to wheat flour pasting or thermal properties, and thus affects final food qualities. Fourteen flour blends with amylose content ranges of < 1 to 29% were used to study tortilla production and quality parameters. Reduced amylose contents decreased dough stickiness and pliability; low amylose doughs were also very smooth in appearance. Very low flour amylose content was associated with earlier tortilla puffing and poor machinability during baking, darker color, low opacity, larger diameters, and reduced flexibility after storage. Tortilla texture analysis indicated that lowering amylose content gave fresh tortillas higher extensibility; after three or more days storage, however, low amylose flours required more force to break the tortillas and the rupture distances became shorter. These results, as reflected in covariate analysis, were not significantly reflected by the flour blend's protein content, swelling volume/power, SDS-sedimentation volume, mixograph dough development time, or mixograph tolerance score. Based on our observation of an initial increase in extensibility with reduced-amylose tortillas, adding 10-20% waxy flour into wild-type flours should be ideal for restaurant (on-site) tortilla production or circumstances where tortillas are consumed shortly (within a day) after production. The optimal flour amylose content for hot-press wheat tortilla products is 24-26%.

Asian Salted Noodle Quality: Impact Of Amylose Content Adjustments Using Waxy Wheat Flour, G. Guo, David S. Jackson, Robert A. Graybosch, Anne M. Parkhurst

Department of Food Science and Technology: Faculty Publications

Fourteen flour blends of two natural wild-type wheat (Triticum aestivum L.) flours, 'Nuplains' and 'Centura', blended with one waxy flour sample were characterized and processed to Asian salted noodles. The flour amylose content range was

Gelatin Manufacturing Process And Product, Vesselin D. Miladinov, Aristippos Gennadios, Milford A. Hanna

Department of Food Science and Technology: Faculty Publications

The present invention overcomes the deficiencies of the prior art by providing a process for manufacturing gelatin including cleaning a fowl-based source of collagen; subjecting the fowl-based source of collagen to at least one water extraction to extract gelatin from the collagen source; and separating the gelatin from any resulting by-products, wherein the process does not require an initial acid or lime pretreatment step. The present invention also includes a product made from this process.

Discovering Lactic Acid Bacteria By Genomics, Todd Klaenhammer, Eric Altermann, Fabrizio Arigoni, Alexander Bolotin, Fred Breidt, Jeffrey Broadbent, Raul Cano, Stephane Chaillou, Josef Deutscher, Mike Gasson, Maarten Van De Gutche, Jean Guzzo, Axel Hartke, Trevor Hawkins, Pascal Hols, Robert W. Hutkins, Michiel Kleerebezem, Jan Kok, Oscar Kuipers, Mark Lubbers, Emanuelle Maguin, Larry Mckay, David Mills, Arjen Nauta, Ross Overbeek, Herman Pel, David Pridmore, Milton Saier, Douwe Van Sinderen, Alexei Sorokin, James Steele, Daniel O'Sullivan, Willem De Vos, Bart Weimer, Monique Zagorec, Roland Seizen

Department of Food Science and Technology: Faculty Publications

This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, environmental habitat, and its role in fermentation, bioprocessing, or probiotics. For those projects where genome sequence data were available by March 2002, summaries include a listing of key statistics and interesting genomic features. These efforts will revolutionize our molecular view of Gram-positive bacteria, as up to 15 genomes from the low GC content lactic acid bacteria are expected to be available in the public domain by …

Factors Affecting The Determination Of Threshold Doses For Allergenic Foods: How Much Is Too Much?, Steve L. Taylor, Susan L. Hefle, Carsten Bindslev-Jensen, S. Allan Bock, A. Wesley Burks Jr., Lynn Christie, David J. Hill, Arne Host, Jonathan O'B. Hourihane, Gideon Lack, Dean D. Metcalfe, Denise Anne Moneret-Vautrin, Peter A. Vadas, Fabienne Rance, Daniel J. Skrypec, Thomas A. Trautman, Ingrid Malmheden Yman, Robert S. Zeiger

Department of Food Science and Technology: Faculty Publications

Background: Ingestion of small amounts of an offending food can elicit adverse reactions in individuals with IgE-mediated food allergies. The threshold dose for provocation of such reactions is often considered to be zero. However, because of various practical limitations in food production and processing, foods may occasionally contain trace residues of the offending food. Are these very low, residual quantities hazardous to allergic consumers? How much of the offending food is too much? Very little quantitative information exists to allow any risk assessments to be conducted by the food industry.

Objective: We sought to determine whether the quality and quantity …

Displacement Of Escherichia Coli O157:H7 From Rumen Medium Containing Prebiotic Sugars, Albane De Vaux, Mark Morrison, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

A fed-batch, anaerobic culture system was developed to assess the behavior of Escherichia coli O157:H7 in a rumen-like environment. Fermentation medium consisted of either 50% (vol/vol) raw or sterile rumen fluid and 50% phosphate buffer. Additional rumen fluid was added twice per day, and samples were removed three times per day to simulate the exiting of digesta and microbes from the rumen environment under typical feeding regimens. With both types of medium, anaerobic and enteric bacteria reached 10¹⁰ and 10⁴ cells/ml, respectively, and were maintained at these levels for at least 5 days. When a rifampin-resistant strain of …

Reduction Of Moniliformin During Alkaline Cooking Of Corn, Graciela Pineda-Valdes, Dojin Ryu, David S. Jackson, Lloyd B. Bullerman

Department of Food Science and Technology: Faculty Publications

The incidence of moniliformin (MON) producing Fusarium spp. in selected corn (Zea mays L.) samples from Mexico and the United States and the effects of alkaline cooking and the tortilla manufacturing processes on the reduction of MON were determined. The percentage of infected kernels with Fusariumspp. ranged from 0 to 22% in eight food-grade corn samples, including six from Mexico and two from the United States. Complete (100%) reduction of MON was observed when a naturally contaminated com sample containing 1.4 µg of MON/g of corn was used in a pilot-scale alkaline cooking and tortilla manufacturing process. In …

Enzymatic Process For Nixtamalization Of Cereal Grains, David S. Jackson, Deepak Sahai

Department of Food Science and Technology: Faculty Publications

Disclosed are novel methods of producing food compositions by the use of an enzymatic digestion of the component parts of whole portions of cereal grains, and grain materials, to impart advantageous qualities to the resulting flour and dough related products produced therefrom. The present invention specifically relates to the fields of making flour and dough, used for totillas, corn chips, totilla chips, snacks, half-products and related products from the component parts and whole portions of cereal grains, and related materials.

Water-Resistant Degradable Foam And Method Of Making The Same, Gerald Biby, Milford Hanna, Qi Fang

Department of Food Science and Technology: Faculty Publications

A foam that is the extrudate of a mixture of a biodegradable polymer, starch, talc, and a blowing agent is provided. This foam is made by extruding a mixture of the above-listed components. This foam is water-resistant and in some variations waterproof making it an effective packing material. Still further, this foam is biodegradable, and thus, it can be disposed without creating environmental waste. In addition, the foam may be extruded into sheets and then therm-formed to form various articles.

Ancestral Divergence, Genome Diversification, And Phylogeographic Variation In Subpopulations Of Sorbitol-Negative, Β-Glucuronidase- Negative Enterohemorrhagic Escherichia Coli O157, Jaehyoung Kim, Joseph Nietfeldt, Jingliang Ju, John Wise, Narelle Fegan, Patricia Desmarchelier, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

The O157:H7 lineage of enterohemorrhagic Escherichia coli is a geographically disseminated complex of highly related genotypes that share common ancestry. The common clone that is found worldwide carries several markers of events in its evolution, including markers for acquisition of virulence genes and loss of physiological characteristics, such as sorbitol fermentation ability and β-glucuronidase production. Populations of variants that are distinct with respect to motility and the sorbitol and β-glucuronidase markers appear to have diverged at several points along the inferred evolutionary pathway. In addition to these variants, distinct subpopulations of the contemporary non-sorbitol-fermenting, β-glucuronidase-negative O157:H7 clone were recently detected …

Role Of ΣB In Adaptation Of Listeria Monocytogenes To Growth At Low Temperature, Lynne A. Becker, Stefanie N. Evans, Robert W. Hutkins, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

The activity of σ^B in Listeria monocytogenes is stimulated by high osmolarity and is necessary for efficient uptake of osmoprotectants. Here we demonstrate that, during cold shock, σ^B contributes to adaptation in a growth phase-dependent manner and is necessary for efficient accumulation of betaine and carnitine as cryoprotectants.

Cytoplasmic Filament-Deficient Mutant Of Treponema Denticola Has Pleiotropic Defects, Jacques Izard, William A. Samsonoff, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

In Treponema denticola, a ribbon-like structure of cytoplasmic filaments spans the cytoplasm at all stages of the cell division process. Insertional inactivation was used as a first step to determine the function of the cytoplasmic filaments. A suicide plasmid was constructed that contained part of cfpA and a nonpolar erythromycin resistance cassette (ermF and ermAM) inserted near the beginning of the gene. The plasmid was electroporated into T. denticola, and double-crossover recombinants which had the chromosomal copy of cfpA insertionally inactivated were selected. Immunoblotting and electron microscopy confirmed the lack of cytoplasmic filaments. The mutant was further …

Fermentation Of Fructooligosaccharides By Lactic Acid Bacteria And Bifidobacteria, Handan Kaplan, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Lactic acid bacteria and bifidobacteria were screened of their ability to ferment fructooligosaccharides (FOS) on MRS agar. Of 28 strains of lactic acid bacteria and bifidobacteria examined, 12 of 16 Lactobacillus strains and 7 of 8 Bifidobacterium strains fermented FOS. Only strains that gave a positive reaction by the agar method reached high cell densities in broth containing FOS.

Genetic And Structural Analyses Of Cytoplasmic Filaments Of Wild-Type Treponema Phagedenis And A Flagellar Filament-Deficient Mutant, Jacques Izard, William A. Samsonoff, Mary Beth Kinoshita, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

Unique cytoplasmic filaments are found in the treponeme genus of spirochete bacteria. Their function is unknown, but their location underneath the periplasmic flagellar filaments (PFF) suggests a role in motility and/or cell structure. To better understand these unique structures, the gene coding for the cytoplasmic filaments, cfpA, was identified in various treponemal species. Treponema phagedenis cfpA was 2,037 nucleotides long, and the encoded polypeptide showed 78 to 100% amino acid sequence identity with the partial sequence of CfpA from T. denticola, T. vincentii, and T. pallidum subsp. pertenue. Wild-type T. phagedenis and a …

Insertional Inactivation Of Treponema Denticola Tap1 Results In A Nonmotile Mutant With Elongated Flagellar Hooks, Ronald J. Limberger, Linda L. Slivienski, Jacques Izard, William A. Samsonoff

Department of Food Science and Technology: Faculty Publications

The treponemal fla operon is comprised of numerous motility-related genes; however, the initial gene of this operon, tap1, has no known function. A recently developed system to generate specific mutants in Treponema denticola was utilized to determine if Tap1 was essential for motility. T. denticola tap1 and flanking DNA were identified, cloned, and sequenced, and a suicide plasmid that contained tap1 interrupted with an erythromycin resistance cassette (ermF and ermAM) was constructed. Because of potential polar effects from this cassette, a second plasmid that contained tap1 interrupted with a modified erythromycin resistance cassette that lacked the putative ermF transcription …

Mutational Analysis Of The Role Of Hpr In Listeria Monocytogenes, Douglas P. Christensen, Andrew K. Benson, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

The regulatory role of HPr, a protein of the phosphotransferase system (PTS), was investigated in Listeria monocytogenes. By constructing mutations in the conserved histidine 15 and serine 46 residues of HPr, we were able to examine how HPr regulates PTS activity. The results indicated that histidine 15 was phosphorylated in a phosphoenolpyruvate (PEP)-dependent manner and was essential for PTS activity. Serine 46 was phosphorylated in an ATP-dependent manner by a membrane-associated kinase. ATP-dependent phosphorylation of serine 46 was significantly enhanced in the presence of fructose 1,6-diphosphate and resulted in a reduction of PTS activity. The presence of a charge …

Octamer-Based Genome Scanning Distinguishes A Unique Subpopulation Of Escherichia Coli O157:H7 Strains In Cattle, Jaehyoung Kim, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

Multilocus-genotyping methods have shown that Escherichia coli O157:H7 is a geographically disseminated clone. However, highresolution methods such as pulse-field gel electrophoresis demonstrate significant genomic diversity among different isolates. To assess the genetic relationship of human and bovine isolates of E. coli O157:H7 in detail, we have developed an octamer-based genome-scanning methodology, which compares the distance between over-represented, strand-biased octamers that occur in the genome. Comparison of octamer-based genome-scanning products derived from >1 megabase of the genome demonstrated the existence of two distinct lineages of E. coli O157:H7 that are disseminated within the United States. Human and bovine isolates are nonrandomly …

Identification Of The Gene Encoding The Alternative Sigma Factor ΣB From Listeria Monocytogenes And Its Role In Osmotolerance, Lynne A. Becker, Mehmet Sevket Cetin, Robert W. Hutkins, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

Listeria monocytogenes is well known for its robust physiology, which permits growth at low temperatures under conditions of high osmolarity and low pH. Although studies have provided insight into the mechanisms used by L. monocytogenes to allay the physiological consequences of these adverse environments, little is known about how these responses are coordinated. In the studies presented here, we have cloned the sigB gene and several rsb genes from L. monocytogenes, encoding homologs of the alternative sigma factor σ^B and the RsbUVWX proteins, which govern transcription of a general stress regulon in the related bacterium Bacillus subtilis. …

Cloning And Expression Of The Listeria Monocytogenes Scott A Ptsh And Ptsi Genes, Coding For Hpr And Enzyme I, Respectively, Of The Phosphotransferase System, Douglas P. Christensen, Andrew K. Benson, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

The phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS) utilizes high-energy phosphate present in PEP to drive the uptake of several different carbohydrates in bacteria. In order to examine the role of the PTS in the physiology of Listeria monocytogenes, we identified the ptsH and ptsI genes encoding the HPr and enzyme I proteins, respectively, of the PTS. Nucleotide sequence analysis indicated that the predicted proteins are nearly 70% similar to HPr and enzyme I proteins from other organisms. Purified L. monocytogenes HPr overexpressed in Escherichia coli was also capable of complementing an HPr defect in heterologous extracts of Staphylococcus aureus ptsH …

United States Patent: Silicalite Membrane And Method For The Selective Recovery And Concentration Of Acetone And Butanol From Model Abe Solutions And Fermentation Broth, Michael M. Meagher, Nasibuddin Qureshi, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Silicalite. silicalite filled polymer membrane. and process for the selective adsorption of acetone and butanol from aqueous solutions thereof. The silicalite. silicalite filled polymer membrane. and process are particularly suited to the removal of acetone and butanol from Closfridium acetobutylicum fermentation media in that the membrane is not fouled by the fermentation media and may be used without removing the cells from the fermentation media. The silicalite and silicalite filled polymer membrane show excellent selectivity to the adsorption of acetone and butanol relative to the ethanol, acetic acid, and butyric acid components of the fermentation media.

An Evaluation Of The Sensitivity Of Subjects With Peanut Allergy To Very Low Doses Of Peanut Protein: A Randomized, Double-Blind, Placebo-Controlled Food Challenge Study, Jonathan O'B. Hourihane, Sally A. Kilburn, Julie A. Nordlee, Susan L. Hefle, Steve L. Taylor, John O. Warner

Department of Food Science and Technology: Faculty Publications

The minimum dose of food protein to which subjects with food allergy have reacted in double-blind, placebo-controlled food challenges is between 50 and 100 mg. However, subjects with peanut allergy often report severe reactions after minimal contact with peanuts, even through intact skin.

Objective: We sought to determine whether adults previously proven by challenge to be allergic to peanut react to very low doses of peanut protein.

Methods: We used a randomized, double-blind, placebo-controlled food challenge of 14 subjects allergic to peanuts with doses of peanut ranging from 10 μg to 50 mg, administered in the form of …

Listeria Monocytogenes Scott A Transports Glucose By High-Affinity And Low-Affinity Glucose Transport Systems, Corinne Parker, Robert W. Hutkins

Department of Food Science and Technology: Faculty Publications

Listeria monocytogenes transported glucose by a high-affinity phosphoenolpyruvate-dependent phosphotransferase system and a low-affinity proton motive force-mediated system. The low-affinity system (K_m = 2.9 mM) was inhibited by 2-deoxyglucose and 6-deoxyglucose, whereas the high-affinity system (K_m= 0.11 mM) was inhibited by 2-deoxyglucose and mannose but not 6-deoxyglucose. Cells and vesicles artificially energized with valinomycin transported glucose or 2-deoxyglucose at rates greater than those of de-energized cells, indicating that a membrane potential could drive uptake by the low-affinity system.

Effects Of Thermal Processing On The Stability Of Fumonisin B2 In An Aqueous System, Lauren S. Jackson, Jason J. Hlywka, Kannaki R. Senthil, Lloyd B. Bullerman

Department of Food Science and Technology: Faculty Publications

Fusarium moniliforme, a prevalent fungal contaminant of corn, has been implicated in several animal diseases including equine leukoencephalomalacia (ELEM) (Thiel et al., 1991), porcine pulmonary edema (PPE) (Harrison et al., 1990), liver toxicity and liver cancer in rats (Voss et al., 1993), and esophageal cancer in humans (Sydenham et al., 1991; Rheeder et al., 1992). The fumonisins, which are secondary metabolites of F. moniliforme, are believed to be responsible for many of the toxicological effects in animals and humans (Marasas et al., 1988; Wilson et al., 1992; Colvin et al., 1993, Gelderblom et al., 1991; Sydenham et al., …

Identification Of A Brazil-Nut Allergen In Transgenic Soybeans, Julie A. Nordlee, Steve L. Taylor, Jeffrey A. Townsend, Laurie A. Thomas, Robert K. Bush

Department of Food Science and Technology: Faculty Publications

Background: The nutritional quality of soybeans (Glycine max) is compromised by a relative deficiency of methionine in the protein fraction of the seeds. To improve the nutritional quality, methionine-rich 2S albumin from the Brazil nut (Bertholletia excelsa) has been introduced into transgenic soybeans. Since the Brazil nut is a known allergenic food, we assessed the allergenicity of the 2S albumin.

Methods: The ability of proteins in transgenic and nontransgenic soybeans, Brazil nuts, and purified 2S albumin to bind to IgE in serum from subjects allergic to Brazil nuts was determined by radioallergosorbent tests (four …

Biodegradable Polymers, Milford A. Hanna

Department of Food Science and Technology: Faculty Publications

To prepare a biodegradable plastic, biodegradable materials such as starches and a non-biodegradable polymer such as a polystyrene, polyurethane, polyethylene, polypropylene, or polycarbonate are treated: (1) under heat, pressure and reagents to break the polymers; and (2) by adding to them an oxidizing agent. This treatment forms and/or makes available reactive groups for bonding: (1) on the biodegradable material groups such as aldehyde or hydroxyl groups in the case of the carbohydrates and amine groups in the case of proteins and certain other compounds such as urea; and (2) on the non-biodegradable plastic groups such as aldehydes, methyl, propyl, ethyl, …