• Optimize agronomic systems and environmental practices, including fertilization and rotation that minimize inoculum potential of Aspergillus flavus and other mycotoxin- producing fungi while maximizing corn yield and profits in the Mid-south USA.
• Gain an understanding of the role of crop management practices on the ecology of Aspergillus flavus and aflatoxin contamination in order to optimize the application of competitive exclusion products.
• Develop economical biologically-based strategies, including antagonists from soil fungi and bacteria, microbial competitors and antagonists, and natural compounds from biological sources, to minimize mycotoxins and their respective fungi in corn, and continue ecological studies on Aspergillus populations under various management strategies, e.g., rotations, tillage, and cover crops, and herbicide-resistant crops.
• Evaluate insect-resistant and susceptible maize lines for insect damage and aflatoxin and fumonisin contamination.

• Evaluate potassium fertility as a means to decrease mycotoxins.
• Evaluate corn maturity as a management practice to avoid heat and/or drought stress and mycotoxins.
• Evaluate double-cropped corn for mycotoxin contamination.
• Evaluate corn-soybean rotation to reduce fungal inoculum.
• Characterize population dynamics of Aspergillus propagules in soil, air, insects and corn at various ontogeny in BT and conventional corn.
• Compare efficacy of non-toxigenic A. flavus strains as biocontrol agents.
• Optimize surfactant concentration and formulation for improvement of efficacy of non- toxigenic strains.
• Determine efficacy of Pichia anomala to control aflatoxin and fumonisin.
• Identify and characterize bacteria from corn field soils as biocontrol agents of Aspergillus and Fusarium.
• Isolate and identify factors in corn-earn-worm- resistant corn silks for control of insects and mycotoxins.

1. Determine agronomic, environmental, and genetic resistance factors that influence aflatoxins, fumonisims, and other mycotoxins on corn production in the mid south.
2. Develop agronomic systems that maximize corn yields and profits while minimizing toxin development.
3. Integrate mycological, agronomic, and corn genetic resistance into an improved strategy.

1. Determine if addition of dietary alfalfa will prevent colonization of Salmonella Enteritidis in the crop of chickens undergoing molting and what characteristics in the crop microenvironment are associated with this type of induced molt.
2. Understand the potential role of the gastrointestinal tract for Salmonella Enteritidis pathogenesis while birds are undergoing molting and if key characteristics in the chicken crop microenvironment can be linked with limiting S. Enteritidis colonization and invasion.

Salmonellosis is one of the most common foodborne diseases with an estimated 800,000 to 4 million human infections reported each year in the United States alone. During the past 10-15 years, the number of cases of gastroenteritis due to Salmonella enterica subspecies enterica serovar Enteritidis (SE) infections has greatly increased in the United States and Europe and by 1995, SE comprised 25% of all foodborne Salmonella isolates. Between 1985 and 1991, over 80% of SE infections in the United States were associated with table eggs and this may be linked to the specific stressful management practice of inducing a molt to stimulate multiple egg-laying cycles in hens. Sixty percent of the estimated 240 million laying hens nationwide are force molted with the practice growing more popular. Feed withdrawal is the primary method used in the layer industry to induce molting. However, feed withdrawal dramatically enhances SE recovery from crops, increases invasion of organs in chickens and increases horizontal transfer in flocks. The poultry industry needs alternative molting procedures that do not require feed withdrawal but allow managers to keep the economic advantages of recycling laying hens by molting without causing a SE contamination problem. In this proposal our objective is to determine whether an alfalfa molt induction will minimize SE invasion in laying hens. This will provide the poultry industry with a scientifically based rationale for alfalfa as a possible management alternative to reduce molting as a major risk for SE contamination.

1. Isolate and determine the efficacy of bacteriophage to reduce food borne human pathogen contamination of poultry products and to prevent poultry diseases.
2. Determine the effects of stress on the innate immune system of turkeys and resulting susceptibility to bacterial infections of food safety importance, develop appropriate interventions to decrease pathogens load and susceptibility to disease, and develop assays to measure those effects.

Thorough literature review to evaluate know factors influencing gut microflora, generate community patterns based on 16SrRNA gene T-RFLP analysis and establish key members of the porcine microbial community increasing in abundance in repsonse to fiber in the diet and design DNA microarray for the purpose of efficient analysis of the GO microbial community.

The long-term objectives for our research are to

1. Determine the occurrence of Salmonella spp. (including Salmonella typhimurium DT104) and Campylobacter spp. (including Campylobacter jejuni and coli) on organic (no use of antibiotics) and conventional farms in Midwestern farms producing slaughter pigs,
2. Understand the epidemiological features of shedding and prevalence of these bacteria,
3. Understand the importance of antibiotic use as a determinant of antibiotic susceptibility,
4. Identify risk factors related to increased antimicrobial resistance in Salmonella spp. and Campylobacter spp., and those management factors used to replace the need for antibiotics,
5. Investigate production efficiency in organic farms as compared to conventional farms, and 6) educate the swine production industry regarding the need for prudent use of antmicrobials.

A total of 70 conveniently selected swine herds (35 organic farms and 35 conventional farms) will be used for this study. To be included in the study, farms must market at least 2000 slaughter pigs per annum. Organic farms must have adhered to the rules and regulations of their organic association such that no antibiotics were used on the farm for at least 3 years. Each herd will be visited once in the summer and once in the winter. At each visit, 15 randomly identified pigs will be selected for sampling from the group of pigs that is closest to go to slaughter. These older pigs have had the greatest potential exposure to antibiotics. Also, the older animals are closer to enter the human food chain where they can expose people to foodborne pathogens. Data will be collected from all farms regarding management factors such as nutrition, disease control methods, physical facilities, farm personnel, animal isolation and quarantine, reproduction, animal density, and measures of herd productivity and efficiency. Questions will focus on those procedures and practices which are used to replace the need for antimicrobials. Once received in the laboratory, samples will be processed in accordance with standard diagnostic microbiological procedures for each animal species. Fecal samples will be enriched in Tetrathionate broth and then plated onto Brilliant Green and XLT4 agar plates. Fecal samples will also be inoculated into Campy medium and incubated under micro-aerophilic conditions. The bacteria will be identified using conventional identification schemes. The identification scheme used will be Gram stain dependent and may include, but not be limited to, Gram staining, catalase, coagulase, API 20E, API 20NE, TSI, MIO, and Urea. Once the bacteria have been identified, they will be sub-cultured for in vitro susceptibility testing using the broth microbroth dilution as described in the National Committee for Clinical Laboratory Standards (NCCLS) M31-T document. Once the testing is complete, multiple colonies from fresh subcultures will be suspended in sterile defibrinated sheep blood and frozen at -70 degrees Celsius. In vitro antimicrobial susceptibility testing for Salmonella and E. coli will be determined using a broth dilution breakpoint method in which the antimicrobials are prepared commercially in a microtitre plate format (Sensititre Ltd, Crawley, UK). In vitro susceptibility testing for Campylobacter will be determined using the 'Etest' for Antimicrobial Resistance Testing' (AB Biodisk North America Inc., New Jersey, U.S.A.).

Microbial and clinical data show that increasing bacterial resistance is making it more difficult to treat serious bacterial infections in both animals and humans. Reports suggest that the use of antibacterial agents in animals is a cause of this problem. This study is designed to determine an association between the use of antimicrobial agents in swine production and the presence of antimicrobial resistance in human foodborne pathogens isolated from slaughter pigs.

1. Determine the effect of antimicrobial therapy for treatment of clinical and subclinical mastitis on the development of antimicrobial resistance in Enterobacteriaceae present in feces of dairy cattle.
2. Develop and apply prudent antimicrobial-use guidelines specific for clincial and subclinical mastitis therapy in dairy cattle populations.
3. Disseminate thes guidelines and supporting information to dairy producers adn veterinarians serving dairy herd clients.

The purpose of this study is to determine the effect of antimicrobial treatment on the development of resistance in bacteria present in cattle, develop and apply prudent antimicrobial-use guidelines specific for dairy cattle and to disseminate these guidelines to dairy producers and their veterinarians.

1. Use prospective longitudinal monitoring of dairy cattle populations to investigate the impact of standard antimicrobial use practices in dairy herds on the development of antimicrobial resistance of enteric bacteria in dairy cattle populations.
2. Collaborate with dairy producers and their herd veterinarians who are active participants in the study to interpret the research results and develop appropriate and practical prudent antimicrobial-use guidelines for dairy cattle populations.