Increased bioaerosol loadings in downwind plumes from concentrated animal feeding operations (CAFOs) may increase the risk for allergy and infection in humans. In this study, we monitored airborne concentrations of culturable bacteria and fungi at upwind (background) and downwind sites at a 10,000 milking cow dairy over the course of a year. The average bacterial concentrations at the upwind site were 8.4 9 10 3 colony forming units (CFU) m -3and increased to 9.9 9 10 5 CFU m -3 at the downwind edge of the cattle lots, decreasing to 6.3 9 10 4 CFU m -3 200 m farther downwind. At the same sites, the average fungal concentrations were 515, 945, and 1,010 CFU m -3 , respectively. Significant correlations between the ambient weather conditions and airborne fungal and bacterial concentrations were identified. Sequence analysis of PCR-amplified DNA from bacterial clones and fungal isolates revealed genus and species level differences between upwind and downwind sites. Although we could not cultivate gram-negative bacteria, bacterial clones at downwind sites identified as being gram-negative matched with the following genera: Acinetobacter, Bradyrhizobium, Escherichia, Idiomarina, Methylobacterium, Ralstonia, and Novosphingobium. Fungal isolates from downwind matched with the following genera:

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We measured Escherichia coli, and Enterococcus sp. numbers in soil and on fresh radish (Raphanus sativus L.) at 1, 7, 14, 28, 54, and 84 days after the addition of high and low amounts of solid dairy manure in combination with chisel tillage to a 20 cm depth (deep) or roller tillage to a 10 cm depth (shallow). When the high or low amount of solid dairy manure was added to the soil, E. coli populations in soil were higher in the 54 days following manure addition compared to the control treatment. Dairy manure addition increased Enterococcus sp. in soils compared to the control treatment for the entire 84 days sampling period. At harvest, which was 84 days after application, we did not detect E. coli in radish in rhizosphere soil or on radish roots. Addition of solid dairy manure increased Enterococcus sp. numbers in radish rhizosphere soil and on radish roots. We suggest that fresh animal manure be applied to soil at least 120 days prior to planting to allow die-off of human pathogenic bacteria and reduce the incidence of bacterial adhesion on or bacterial colonization of ready to eat vegetables.