AUTHOR=Nadala Cesar , Themeli Eni , Forghani Fereidoun , Ha Youngsil , Han Sukkyun , Shapovalova Anna , Roach John , Kim Seong Hong , Thorson Jennifer L. M. , Lee Joo-Young , Spear Matthew , Buhrman Benjamin , Chiu Kevin , Mullane Niall , Samadpour Mansour 
  
TITLE=Detection and characterization of Clostridium botulinum isolated from powdered infant formula
  
JOURNAL=Frontiers in Microbiology
  
VOLUME=Volume 17 - 2026
  
YEAR=2026
  
URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2026.1800624
  
DOI=10.3389/fmicb.2026.1800624
  
ISSN=1664-302X
  
ABSTRACT=IntroductionAs a part of an ongoing investigation of the 2025 multistate outbreak of infant botulism linked to consumption of powdered infant formula (PIF), various samples – including unopened containers of PIF and base powder (bulk PIF before packaging) – were analyzed for the presence of Clostridium botulinum.MethodsSamples were screened using a tiered analytical approach: anaerobic enrichment followed by real-time PCR targeting botulinum neurotoxin-associated genes, confirmatory PCR, amplicon sequencing, colony isolation, and whole-genome sequencing (WGS). C. botulinum was detected in both the finished product and base powder.ResultsGenomic analysis revealed genetic identity between isolates from one finished product lot and a base powder, while an isolate from another lot was distinct. Importantly, detection occurred in samples with non-detectable sulfite-reducing clostridia (SRC).ConclusionResults of this study demonstrate that indicator-based screening (such as SRC enumeration) even if it had been in place before the outbreak, would not have prevented its occurrence. Positive linkage of an infant botulism outbreak to PIF should compel manufacturers to recognize C. botulinum as a hazard reasonably likely to occur in certain ingredients, necessitating the design and implementation of specific preventative controls.