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

backgroundSpring 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.

resultsSalmonella was isolated and semi-quantified by selective culture and Escherichia coli was enumerated on MI agar, from 60 water samples collected from 21 ponds on 11 farms from June to October. Aliquots of pre-enrichment/enrichment broths that yielded Salmonella isolates by selective culture were subjected to serotyping with CRISPR-SeroSeq. Salmonella was undetectable in 11 of the 21 ponds, while 10 ponds from seven of the 11 farms were positive at least once. Farm, but not month of collection, was a significant factor for Salmonella detection but not for Salmonella estimates. Levels ranged from 0.03-2.9 MPN L

conclusionLow 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. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.