Animal Waste, Water Quality and Human Health

94Animal Waste, Water Quality and Human Health2002), with the herd-level animal prevalence ranging from 0 to 37% for lactatingdairy cattle (Callaway et al. 2005). The prevalence of Salmonella in farmenvironmental samples in one study was shown to be 57.3%, 17.9% and 16.2%in swine farms, dairy farms, and poultry farms, respectively (Rodriguez et al.2006). In New York dairies (440 dairy farms enrolled) Salmonella was isolatedfrom 1.5% of milk filters (Hassan et al. 2000). In swine farms in the midwesternUSA, the mean prevalence for Salmonella was 5% (Bahnson et al. 2006). TheEuropean Food Safety Agency reported that among EU member states in 2007there was a mean Salmonella prevalence of 2.9% in laying hens (range 0–22.2%), 3.7% for broilers (range 0 to 25.3%), 10.6% for ducks (range 0 to21.7%), 9.3% for geese (range 0 to 21.2%), and 7.8% for turkeys (range 0 to14.8%) (EFSA, 2009). In the same report, Salmonella prevalence ranged from 0to 19.3% in five EU member states reporting and from 1.6 to 7.7% for cattle intwo member states reporting.Serotypes of Salm. enterica in poultry farms in the USA include Typhimurium,Montevideo, Kentucky & Enteritidis (Liljebjelke et al. 2005) and eggs are afrequent source of Salm. enterica Enteritidis (Hogue et al. 1997).3.3.4 Survival of zoonotic bacterial pathogens in thefarm environmentE. coli O157 survives for at least 50 days in cattle faeces (Maule, 2000). Survival ofthe organism in bovine manure is dependent on the temperature withviable organisms found for 49 to 56 days at 22°C and 63 to 70 days at 5°C(Wang et al. 1996). The organism can survive up to 47 days in bovine manureheaps and up to 21 months in non-aerated bovine manure heaps (Kudva et al.1998). Himathonkham et al. (1999) suggest that bovine manure be held for 105days at 4°C or 45 days at 37°C to achieve a 5 log reduction in levels of E. coliO157 and Salm. enterica serovar Typhimurium.It has also been shown that E. coli O157:H7 survives well in soil. An inoculum of10 8 CFU/g of the organism was shown to decline between 1 to 2 logs after 130 daysin soil cores of rooted grass. Jiang et al. (2002) reported detection of the pathogen fornearly 200 days in bovine manure amended soil and reported that survival was afunction of the soil temperature, ratio of manure to soil and the presence of theindigenous microflora in the soils. Survival of E. coli O157:H7 in soilwhere bovine manure slurry has been applied is significantly longer than withsurface application of solid bovine manure. However, for Salm. enterica serovarTyphimurium survival appears to be equivalent in manure and slurry-appliedsoils (Semenov et al. 2009). Campylobacters are particularly sensitive to factorsin the external environment such as desiccation. Survival of Campylobacter in