Microbiological Quality of Litter from Poultry Houses in Mississippi.

Poultry concentrated animal feeding operations generate approximately 1 kg of litter per broiler put to market.  The majority of this litter is applied as a fertilizer to either forage or row crops.  Though much is known about the fertilizer nutrient value associated with this manure, little is actually known about the microbial quality of the litter.  The purpose of this research is to gain a better understanding of the microbial quality of poultry litter manure throughout Mississippi, related to source, management and intra-house sample location.  Poultry litter samples were collected from 30 broiler production houses in Mississippi.  Samples were specifically collected to ascertain intra-house differences associated with location proximal to water and feed lines, fan exhaust, and side wall locations.  A composite sample comprised of five, 100 g grab samples was collected at each site yielding four samples per house.  Samples were individually homogenized using a stomacher prior to analysis, and were analyzed for the presence of total and thermal-tolerant coliforms, Escherichia coli, Clostridium perfringens, staphylococci, and enterococci.  A real-time (quantitative) polymerase chain reaction (PCR) assay targeting the 16S rRNA gene was used to quantify total bacterial numbers per g of litter.  In addition, food-borne pathogens such as Listeria, Campylobacter, and Salmonella were also investigated using a combination enrichment PCR assay.  There were differences between poultry integrators, despite similar approaches to operation and management styles; in addition intra-house differences were related to proximity to fans, water, and feeder lines.