Purpose: Therefore, a study was performed to investigate the prevalence and diversity of Salmonella spp. in irrigation water, poultry litter and amended soils on ESV.
Methods: Irrigation pond water and well water, poultry litter, and soils were sampled from four vegetable farms, three chicken farms, and four pairs of representative farms with or without chicken litter fertilization on ESV, respectively. The most probable number (MPN) method was used to detect Salmonella spp. in the samples. Presumptive Salmonella colonies were confirmed by the cross-streaking method. Molecular serotyping was carried out to determine the Salmonella serovars.
Results: Spatial (pond location) and temporal (month) differences were observed in the presence of Salmonella in surface pond water. The prevalence of Salmonella spp. in four tested ponds from farms A, B, C and D were 14.8, 11.1, 18.5 and 35.2%, respectively. Salmonella levels were significantly higher in spring and fall, compared to in winter (P < 0.05). While the prevalence of Salmonella spp. in well water samples was low, several well water samples did test positive for Salmonella in Nov 2013/2014 and Dec 2014. Most houses of the three tested chicken farms were Salmonella positive during the study period, except for the period from Nov 2013 to Jan 2014. Salmonella was found to survive up to four months in poultry litter amended soils from the tested farms.
Significance: This research reported the contamination of Salmonella spp. in relationship to irrigation water sources and chicken manure used for vegetable production. These data provided important information on the prevalence of Salmonella in a major agricultural region for food safety risk assessment.