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The goals of the work proposed here are: to determine inactivation/survival rates for enteric bacterial pathogens and norovirus from soils receiving manure or Class B biosolids at agronomic application rates; and to provide identical comparisons of the two residual amendments across multiple southeastern US soil types. <P>
The objectives of the work are: 1) to determine inactivation rates for microbial parameters as related to the manure or biosolids waste matrix; and 2) to determine inactivation rates for microbial parameters as related to soil type and application method. <P>
The results of this study will be related to established USDA-AMS and USEPA regulations for the land application of manure and biosolids to soils intended for the growth of crops and food crops. The results will be compared to current recommendations for the delay of vegetable crop planting for the growth of "organic" crops on manured land and for comparison to USEPA Part 503 rules for the growth of vegetables and crops and grazing on Class B biosolids-treated land.<P>
It is expected that the results will yield inactivation rates for both biosolids and manure-borne bacterial and viral pathogens and indicators for clay and sandy soil types common to the southeastern U.S. Even if the use of manure or biosolids are not sanctioned for the growth of vegetable crops, the presence of these inactivation rates and hence pathogen persistence will aid researchers and investigators in predicting the outfalls associated with pre-harvest farm level contamination of foodborne pathogens. These inactivation rates can be used by risk assessors to develop and incorporate into models whereby time-based bacterial concentration predictions are necessary following an application of biosolids or manure to land or from a contamination event. Due to the inherent differences in each respective organic amendment matrix, soil type, and climate found in the southeastern U.S., this data will prove to be useful as very little data exists for this type of study in the U.S. or specifically in this region of the country. It is expected that at least two publications and presentations at national meetings will come from this work.
NON-TECHNICAL SUMMARY: The land applications of animal manure and biosolids are contentious issues within the public, given recent Salmonella and Escherichia coli foodborne outbreaks. Animal manure, dependent on source, may be a source for Campylobacter spp., Escherichia coli, Salmonella spp., Listeria monocytogenes, Cryptosporidium parvum, and Giardia lamblia. Municipal Class B biosolids, dependent on the source, can harbor some of these bacterial pathogens and parasites, but can also contain human viruses, such as members of the enterovirus group, adenovirus, and norovirus. Pathogen survival in soil can vary under a multitude of climates, agronomic practices, and soil types. To the best of our knowledge, no studies have been conducted in which biosolids and manure were both used and compared under identical soil and climate conditions. A side-by-side comparison of the two residuals is needed because survival of each respective set of pathogens may be entirely dependent on the source matrix, and conclusions about one system may not apply to the other. The goals of the work proposed here are: to determine inactivation/survival rates for enteric bacterial pathogens and norovirus from soils receiving manure or Class B biosolids; and to provide identical comparisons of the two residual amendments across multiple southeastern US soil types. This project will address public-health issues, specifically: routes of contamination of food, survival of foodborne pathogens in the soil, and elucidation of source to environmental pathogen persistence. Manure and biosolids application events and survival of pathogens with respect to each source matrix will be compared using controlled environmental conditions. A combination of cultural and molecular methodologies will be used and inactivation rates will be calculated. This research aims to address issues of long term sustainability of biosolids and manure application to agricultural land. The costs of inorganic fertilizers have increased substantially with the rising cost of petroleum products; as such, alternative fertilizer nutrient sources such as manures and biosolids will be more in demand from crop production sectors of agriculture. It is expected that the results will yield inactivation rates for both biosolids and manure-borne bacterial and viral pathogens and indicators for clay and sandy soil types common to the southeastern U.S. Even if the use of manure or biosolids are not sanctioned for the growth of vegetable crops, the presence of these inactivation rates and hence pathogen persistence will aid researchers and investigators in predicting the outfalls associated with pre-harvest farm level contamination of foodborne pathogens. These inactivation rates can be used by risk assessors to develop and incorporate into models whereby time-based bacterial concentration predictions are necessary following an application of biosolids or manure to land or from a contamination event.
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APPROACH: The purpose is to elucidate the effect of source organic fertilizer residual on the prolonged viability of common food-borne bacterial and viral pathogens in soil in residual amended soil. Two different soil types will be chosen comprising a sandy-loam and clay soil, both typical of the surrounding area. Soils will be applied and incorporated or not incorporated with pathogen inoculated manure or biosolids containing a pathogen cocktail consisting of Escherichia coli O157:H7, Salmonella enterica, Clostridium perfringens, Campylobacter jejuni, Listeria monocytogenes, two types of coliphage, and norovirus. Residuals will comprise Class B municipal biosolids, cattle manure, and swine manure lagoon effluent. A control set of jars will comprise sterile solution added to the residual and soil combinations. All soil and residual combinations will be placed into microcosm jars and will be followed over time with samples collected at time(s) from 0 to 210 days following application of residual. Climate and day and night cycles will be strictly maintained in growth chambers. Microbial measurement will comprise cultural methods consisting of standard plating methodologies and quantitative polymerase chain reaction (qPCR). Upon reaching cultural detection limits, samples will be subjected to qPCR to increase detection limits with pathogen specific primers sets. Direct qPCR will be used to determine the discrepancy between cultural and molecular detection methodologies and will be exclusively used to enumerate norovirus. Inactivation rates will be calculated accordingly for each respective organism and treatment combination. Data collected from this study will be used by risk assessors in determining future pathogen-based environmental regulations and recommendations.