Background: Salmonella enterica subsp. enterica serovar Hartford (antigenic formula 6,7:y:e,n,x) is a serovar of the O:7 (C1) serogroup. Serovar Hartford was previously recovered from non-outbreak cattle herds. Serovar Hartford was found as highly persistent in all low-aw food ingredients.

NCBI PD link for serovar Hartford: https://www.ncbi.nlm.nih.gov/pathogens/isolates/#(taxgroup_name:%22Salmonella%20enterica%22)%20AND%20computed_types:(%22serotype=Hartford%22)

Genetic characteristics: Serovar Hartford has been found to be polyphyletic with two lineages identified and one stand-alone singleton that does not cluster with any other Salmonella Hartford isolates. In a US study, serovar Hartford isolates were found to be pansusceptible to all antimicrobials tested using the Kirby-Bauer method. Additionally, all six Hartford isolates recovered from mesenteric lymph nodes on one of farms were indistinguishable based on pulsed-field gel electrophoresis analysis.

Animal reservoir: Salmonella Hartford was found in chicken, calves, horses, dogs, and wild animals such as wild black bears.

Geographical distribution: Serovar Hartford has been found in the US, Canada, Australia, the UK, Hungary, and China.

Human outbreaks: 

YearLocationAssociated SourceNumber of Cases
2023US: multistateNot identified54
2014US: multistateOrganic sprouted chia powder131
2010US: multistateNot identified 75
1995US: FLUnpasteurized orange juice262

1 Salmonella Newport (20 cases), Salmonella Hartford (7 cases), or Salmonella Oranienburg (4 cases) 

2 Salmonella Gaminara was also involved in this outbreak. 

Border rejections: There have been no recent border rejections linked to this serovar. 

Recalls: There have been no recent recalls linked to this serovar. 

Relevant links:

  1. https://www.liebertpub.com/doi/10.1089/fpd.2017.2303?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed
  2. https://www.sciencedirect.com/science/article/pii/S0362028X22106150
  3. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1547190/full
  4. https://pmc.ncbi.nlm.nih.gov/articles/PMC4652083/
  5. https://www.mdpi.com/2076-2607/11/2/403
  6. https://www.jstor.org/stable/24320783
  7. https://www.fda.gov/food/outbreaks-foodborne-illness/investigations-foodborne-illness-outbreaks
  8. https://archive.cdc.gov/www_cdc_gov/salmonella/newport-05-14/index.html
  9. https://archive.cdc.gov/#/details?url=https://www.cdc.gov/salmonella/2010/restaurant-chain-a-8-4-10.html
  10. https://jamanetwork.com/journals/jama/fullarticle/188128