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United States Department of Agriculture

Agricultural Research Service

Research Project: ENVIRONMENTAL AND GENETIC FACTORS AFFECTING PATHOGEN PERSISTENCE IN ANIMAL WASTE AND TRANSFER TO CROPS
2007 Annual Report


1a.Objectives (from AD-416)
1: The identification of factors contributing to the persistence and horizontal transfer of MAP and other pathogens on dairy farms. We will examine the role alternate protozoan hosts play in MAP persistence and horizontal transfer. We will also perform functional genomic analysis of MAP in the environment to elucidate clues about the strategies employed by this organism for environmental survival. 2: The development of methodologies for the reduction of pathogens in waste. Two of the most common waste treatment methodologies are aerobic and anaerobic digestion, but little is known about the effect these processes have on the microbial population structure, pathogen levels, and volatile compound missions. The bacterial community structure, chemical composition and volatile compounds emitted from animal waste, aerobic and anaerobic digesters, and holding tanks receiving effluent will be characterized. We will also analyze the effect of diet and dietary supplements on the microbial population structure, pathogen levels, and volatile compound emissions from animal waste and animal waste treatment systems. 3: Pathogen transfer from manure and CAFOs (confined animal feeding operations) to crops. We will use high volume aerosol collection and agar impaction devices to collect bacteria from aerosols near CAFOs. Aerosol samples will be evaluated for pathogens using culture and non-culture based methods. We will examine the bacterial community structure and pathogen levels on crops fertilized with waste using culture and non-culture based methods and compare them to those of plants fertilized with only chemical fertilizers. We will study the colonization of crop plants by Salmonella enterica grown in soil amended with manure spiked with pathogens using standard culture and quantitative PCR methods.


1b.Approach (from AD-416)
The goal of this project is to reduce the incidence of foodborne illnesses by reducing the levels of pathogens in animal waste and in CAFO environments. In the next five years we will identify the locations in CAFOs that serve as reservoirs for pathogenic bacteria such as MAP, develop low cost pathogen abatement strategies for contaminated animal waste, examine the effect of diet on pathogen load and evaluate the risk of pathogen transfer from CAFOs to surrounding crop plants via aerosols and from fertilizing crop plants with contaminated manure. FORMERLY: 5325-32000-002-00D; 5325-42000-023-00D. 5325-42000-028-00D combined into this project (4/04). Replaces 5325-32000-005-00D (2/06).


4.Accomplishments
Factors from dairy wastewater lagoons that influence the survival of E. coli O157:H7. Every year millions of Americans are affected by foodborne illnesses such as E. coli O157:H7. At WRRC, scientists in the Foodborne Contaminants Research Unit observed survival of E. coli O157:H7 was inhibited by native microorganisms and certain organic extracts of dairy wastewater. Research studies should help identify specific organisms and naturally-occurring chemicals that may be added to waste and wastewater to reduce pathogens. This accomplishment is aligned with NP108 2006-2010 Action Plan Component 1.1 Pathogens, Toxins, and Chemical Contaminants Preharvest. Specifically this research addresses Problem Statements: 1.1.1 Methodology; 1.1.3 Ecology, Host Pathogen and Chemical Contaminants relationships; and 1.1.4 Intervention Strategies.

Bioenergy production from a mixture of dairy cow manure and food waste. Alternative energy products are needed to reduce our dependence on foreign petroleum; in addition, dairy cow manure must be treated to reduce pathogens which can cause human disease. Dairy manure and food waste can both be used to generate methane, but neither is ideal. Manure is a well buffered substrate that produces methane slowly, and food waste produces methane rapidly but is poorly buffered, which results in the inhibition of methane production. In collaboration with scientists at the University of California at Davis WRRC, Albany, CA scientists discovered that a mixture of food waste and manure digests well, producing methane, reducing pathogens in the waste, and generating a compost suitable as a soil conditioner/fertilizer. This has the potential to produce biofuel and to reduce pathogens in waste and wastewater. This accomplishment is aligned with NP108 2006-2010 Action Plan Component 1.1 Pathogens, Toxins, and Chemical Contaminants Preharvest. Specifically this research addresses Problem Statements: 1.1.1 Methodology; 1.1.3 Ecology, Host Pathogen and Chemical Contaminants relationships; and 1.1.4 Intervention Strategies.

Identification of bacterial populations by flow cytometry. Bacteria that cause foodborne illnesses may be able to travel through the air. Foodborne Contaminants Research scientists at the Western Regional Research Center measured particle size and fluorescence in aerosols from environmental samples to detect bacteria where traditional culture methods would likely fail. Genetic analysis of the non-culturable bacteria suggests their size is characteristic for species, which simplifies identification. This observation will make it easier to study aerosol transport of pathogens. This accomplishment is aligned with NP108 2006-2010 Action Plan Component 1.1 Pathogens, Toxins, and Chemical Contaminants Preharvest. Specifically this research addresses Problem Statements: 1.1.1 Methodology; and1.1.3 Ecology, Host Pathogen and Chemical Contaminants relationships.

Construction of a MAP0482-3 mutant strain of Mycobacterium avium subsp. paratuberculosis. Mycobacterium avium subsp. paratuberculosis (MAP) causes disease in ruminants costing producers millions of dollars each year. MAP is shed from the feces of infected animals and is able to survive for extended periods of time in the environment and infect new hosts. To survive in the environment, MAP expresses different genes by binding regulatory proteins such as MAP0482-3 to target genes. Foodborne Contaminants Research scientists at the Western Regional Research Center collaborated with scientists at the Centers for Disease and Control and Prevention in Atlanta, GA, to create a MAP0482-3 mutant strain that has reduced survival in host cells. This will accelerate study of other genes and gene expression in MAP and help understand persistence of MAP in the environment. This accomplishment is aligned with NP108 2006-2010 Action Plan Component 1.1 Pathogens, Toxins, and Chemical Contaminants Preharvest. Specifically this research addresses Problem Statements: 1.1.1 Methodology; and 1.1.3 Ecology, Host Pathogen and Chemical Contaminants relationships.

Biohydrogen production from fermentation of cheese processing wastewater. The cheese industry produces millions of gallons of processing wastewater annually which must be treated and disposed of at considerable cost to the producers. In collaboration with scientists at the University of California at Davis our Foodborne Contaminants Research scientists produced hydrogen by fermenting cheese waste with specially mixed microbes. Research make a significant discovery of a process, which produces a valuable fuel while reducing waste and wastewater pathogens. This accomplishment is aligned with NP108 2006-2010 Action Plan Component 1.1 Pathogens, Toxins, and Chemical Contaminants Preharvest. Specifically this research addresses Problem Statements: 1.1.1 Methodology; 1.1.3 Ecology, Host Pathogen and Chemical Contaminants relationships; and 1.1.4 Intervention Strategies. Bacterial population dynamics in dairy waste during aerobic and anaerobic treatment and subsequent storage. For environmental and health reasons dairy waste must be treated before application to crop fields. In collaboration with scientists at the University of California at Davis our Foodborne Contaminants Research scientists modeled a typical dairy waste stream, measuring bacteria and water chemistry during different kinds of treatment and subsequent storage. Aerated treatment methods produced a greater change in the type of bacteria present, especially an increase in Proteobacteria and a decrease in Firmicutes, while non-aerated treatment produced different, smaller changes in the bacteria population. These results increase our understanding of how treatment affects the bacterial and chemical composition of waste, which has significant implications for environmental quality and human and animal health. This accomplishment is aligned with NP108 2006-2010 Action Plan Component 1.1 Pathogens, Toxins, and Chemical Contaminants Preharvest. Specifically this research addresses Problem Statements: 1.1.1 Methodology; 1.1.3 Ecology, Host Pathogen and Chemical Contaminants relationships; and 1.1.4 Intervention Strategies.


6.Technology Transfer

Number of non-peer reviewed presentations and proceedings4

Review Publications
Ravva, S.V., Korn, A.M. 2007. Extractable Organic Components and Nutrients in Wastewater Influence the Growth of Escherichia coli 0157:H7 in Dairy Lagoons. Applied and Environmental Microbiology. 73(7):2191-2198.

Last Modified: 7/12/2014
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