Salmonella enterica serovars co‐exist sporadically and at low abundance in US mid‐Atlantic irrigation ponds

BACKGROUND: Spring or rain-fed ponds are frequent features on US mid-Atlantic farms. The need to conduct preharvest agricultural water assessments to identify microbial hazards, as required by the US Produce Safety Rule, highlights knowledge gaps pertaining to pond water adequacy for vegetable production. We sought to evaluate Salmonella enterica in Maryland farm ponds during the vegetable-growing season. Eleven serovars were identified, with type and richness differing by month. Individual ponds yielded one to seven serovars. August and October had the highest richness, with Salmonella Enteritidis and Infantis dominating. Farm was a factor for E. coli counts, which was quantified in all but one sample. No relationship with Salmonella levels was discernible. CONCLUSION: Low levels of Salmonella and sporadic detection suggest that pond water could be amenable to treatment and serve as a manageable, safe, sustainable and affordable preharvest agricultural water type. The information can support vegetable farmer decisions to consider ponds as viable water sources.