Food Science Commons^™

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 …

Nebraska Specialty Cheese Plant 2002, Food Processing Center

Food Processing Center: Reports

Vendors specializing in cheese processing equipment, both new and used, were identified and contacted. They were asked to supply as much information as they could on equipment requirements and costs associated with a “complete” cheese plant in very small (4,000 pounds raw milk/day), small (16,000 pounds raw milk/day), and medium-small (32,000 pounds raw milk/day) plant sizes. It was anticipated that these vendors would be better able to recommend equipment and provide costs for complete cheese making systems (plants) that could function efficiently to produce specialty cheese products. This is opposed to a more “piece meal” approach of putting together equipment …

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 …

Detecting Stress In Animals, Sharon Durham, Ted H. Elsasser

Agricultural Research Magazine

When people get stressed, they seek relief in many ways. Some exercise, some practice specific breathing techniques, and some eat chocolate. Farm animals become stressed, too. In domesticated food animals, stress can affect meat quality, milk production, and general health. But animal stress must often be intuited from clues such as lower-than-anticipated weights and increased illness.

Certain stressful events can be anticipated, for example, birth and weaning. But how do you know if an animal is stressed for some other reason? Ted H. Elsasser of ARS’ Growth Biology Laboratory in Beltsville, Maryland, is investigating nitrated protein as a biomarker of …

Getting Atop Climbing Fern, Marcia Wood, Jesús García

Agricultural Research Magazine

A team of two tiny moths might help stop the spread of Old World climbing fern, an aggressive vine that’s on the march in central and south Florida. With further research, a third moth, a hungry mite, a small beetle, and perhaps other hardworking organisms as well may qualify to join the coterie of pint-sized weedeaters.

Known to botanists as Lygodium microphyllum, Old World climbing fern makes its way up stems and trunks of other plants, forming blankets of lightgreen vegetation.

On the ground, climbing fern creates tough, spongy mats that can easily smother grasses, low-growing shrubs, and small …

Speeding Up Breeding Of Superior Plants, Judy St. John

Agricultural Research Magazine

That oatmeal you ate for breakfast this morning is loaded with healthful compounds known as antioxidants. They help to protect your body from damage caused by molecules known as free radicals. Oats, for instance, are rich in the antioxidants alpha-tocopherol and alpha-tocotrienol.

But what if tomorrow’s oats could provide even more of these health-imparting compounds? That’s a goal of ARS oat researchers at laboratories in several states. Aiding this research is an invaluable tool of modern biotechnology. Known as biomolecular markers, gene markers, or DNA markers, these pieces of genetic material are signposts or clues. They are telltale indicators that, …

Protecting Peanuts From Aflatoxin, Jan Suszkiw, Joe W. Dorner, Marshall C. Lamb

Agricultural Research Magazine

Peanut farmers could soon have a biological pesticide for protecting their crop’s prized seed from fungi that produce aflatoxin—the chief culprits being Aspergillus flavus and A. parasiticus.

Circle One Global, Inc. (COGI), of Cuthbert, Georgia, has applied for an exclusive license on an ARS technique for making the biopesticide from spores of a nontoxigenic, or benign, strain of A. flavus.

In Florida, Georgia, and Alabama—top peanut-producing states— aflatoxin outbreaks from 1993 to 1996 caused losses averaging $26 million annually, ARS economist Marshall C. Lamb estimates. The Peanut Administrative Committee strictly regulates the sale or use of shelled peanuts …

Ars Researchers Winning Battle With Noxious Weed, Daniel Gandolfo, Jesús García

Agricultural Research Magazine

Small victories are being reported by the Agricultural Research Service (ARS) in the war against tropical soda apple (Solanum viarum), a nonnative, invasive weed of pastures, row crops, forests, and urban areas throughout the southeastern United States.

Tropical soda apple (TSA) was first observed in Florida in 1988, causing little concern with fewer than 2,000 acres affected. Just 6 years later, however, researchers estimated that more than 1 million acres were infested. Charles T. Bryson, an ARS research botanist with the Southern Weed Science Research Unit in Stoneville, Mississippi, says researchers believe the resilient weed has now been …

Science Update January 2002, Consuelo M. De Moraes, Brad Morris, Steven M. Valles, Yvette Alonso

Agricultural Research Magazine

Caterpillars—Agents of Their Own Demise

Bean Plants Repel Nematodes

Unlocking the Keys to Cockroach Resilience

Everything You Wanted To Know About Food Safety

Fighting Insect Pests Of Stored Foods, Michael A. Mullen, Franklin H. Arthur, Linda Mcgraw

Agricultural Research Magazine

Anyone who has ever been to a picnic knows insects are drawn to food. That’s why developing new methods to keep insects out of food in packages, warehouses, and processing plants is critical for food manufacturers. New and innovative methods are needed because the industry is challenged to reduce pesticide use while ensuring that food products are insect-free. To meet these challenges, a team of ARS scientists at the Grain Marketing and Production Research Center in Manhattan, Kansas, is working closely with industry.

Keep Out, Bug!

Keeping food in containers is one of the oldest ways to protect food from …

Shortcuts To Disease-Resistant Wheats, Gina L. Brown-Guedira, John P. Fellers, Linda Mcgraw

Agricultural Research Magazine

Everyone likes to take shortcuts in time-consuming tasks. And wheat breeders are no exception. Someday, wheat breeders may be able to use new molecular tools being developed by ARS in collaboration with Kansas State University and the Kansas Wheat Commission.

These tools show promise for reducing the time it takes breeders to move important quality and resistance traits into breeding populations of wheat using conventional breeding techniques. Currently, it can take as long as 10 or more years to develop new wheat varieties.

“Using molecular (or DNA) markers may shorten the task of improving insect and disease resistance while maintaining …

To Keep Rivers Within Bounds : A Channel Erosion Guide, Hank Becker, Jill Lee, Andrew Simon, Doug Shields Jr.

Agricultural Research Magazine

In the world of finance, bank failures tend to get press coverage. But there’s another kind of bank failure that affects the American West: Missouri River bank failures in eastern Montana involve lost soil—not dollars—but still hurt farmers financially.

Just ask Boone Whitmer, who farms 3,000 acres of wheat and alfalfa near Wolf Point. Like most farmers bordering the Missouri River downstream from the Fort Peck dam, he places irrigation pumps along the banks to get water for his crops. But the shifting sand bed of the river can clog pumps with sediment and hit growers like him hard.

“In …

Giving Baculoviruses A Better Edge, Arthur H. Mcintosh, Cynthia L. Goodman, James J. Grasela, Ben Hardin

Agricultural Research Magazine

Scientific advancements built on an understanding of what nature already provides are leading to environmentally friendly crop-pest control by either biological agents or specifically designed synthetic antiinsect compounds. A case in point: research on baculoviruses.

Baculoviruses are rod-shaped DNA viruses, many of which begin their life cycle reproducing inside cells. In the nuclei of caterpillar cells infected with baculoviruses, viral progeny multiply and are incorporated into protective polyhedronshaped protein structures called occlusion bodies. Infected caterpillars die and contaminate the leaf surfaces with the occlusion bodies. Then, healthy caterpillars ingest the occlusion bodies and release the virus when feeding on contaminated …

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.

Supplying Craft Breweries With Locally Produced Ingredients, Food Processing Center

Food Processing Center: Reports

This report summarizes the initial findings of a survey of 52 craft breweries (brewpubs, microbreweries, and regional breweries) in the states of Colorado, Nebraska, Iowa, Missouri, Minnesota, and Wisconsin. The head brewer or owner/operator was surveyed to determine the craft brewing industries’ level of interest in purchasing locally grown and produced grains and locally produced malt, as well as the procurement needs for the ingredients they purchase.

The craft brewing industry, which mushroomed in the early to mid 1990’s, slowed to a crawl in the late 1990’s, however, the industry began to rebound in 2000 as volume for craft brewers …

The Specialty Cheese Market, Food Processing Center

Food Processing Center: Reports

This report is intended to be an overview of the specialty cheese market and the marketing of its products. The report also attempts to uncover some of the opportunities and barriers associated with entering the specialty cheese market. The report begins with a discussion of the recent foodservice and retail industry trends, as well as the way the industry is continuing to promote and expand the specialty cheese market.

The report then turns its focus to what will be identified as the “Four P’s” of specialty cheese. This section is intended to assist individuals, farmers, small and mid-size producers and …

Attracting Consumers With Locally Grown Products, Food Processing Center

Food Processing Center: Reports

This report summarizes the initial findings of a survey of 500 households in the states of Nebraska, Iowa, Missouri and Wisconsin. The primary grocery shopper in the household was surveyed for their attitudes and opinions on locally grown and produced food, organic and all-natural food and meat purchasing behaviors.

To access a respondent’s purchasing behavior, each respondent was asked to rank the importance of twelve attributes in determining the product or brand they purchase. The attributes most important to consumers in the region* include taste, quality, nutrition/healthfulness, and price. Seven in ten respondents said that it was very or extremely …

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 …

Enzymatic Nixtamalization: An Improved Corn Masa Flour Production Process, Deepak Sahai, David S. Jackson

Department of Food Science and Technology: Public Access Records

A major concern during commercial masa or instant masa flour production is the proper disposal of the excess waste water generated from the nixtamalization process. Nixtamalization causes partitioning of corn solids between nixtamal and waste water. It has been estimated that corn solids loss during nixtamalization varies between 5-14% depending on corn type & quality. Nejayote waste is highly alkaline, with high chemical and biological oxygen demands (BOD & COD) and is considered an environmental pollutant. A typical corn nixtamalization facility processing 200 US tons of corn every day, uses over 50 gallons of water per minute and generates nearly …

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 …