Enrichment dynamics of Listeria monocytogenes and the associated microbiome from naturally contaminated ice cream linked to a listeriosis outbreak

Microbiota that co-enrich during efforts to recover pathogens from foodborne outbreaks interfere with efficient detection and recovery. Here, efficiency and dynamics of co-enriching microbiota during recovery of Listeria monocytogenes from naturally contaminated ice cream samples linked to an outbreak are examined using three methods: 1) 48 hour enrichment in buffered Listeria enrichment broth (BLEB); 2) 24 hour enrichment in Half-Fraser broth (HFB), followed by 24 hour in Fraser broth (FB); and 3) 24 hour enrichment in University of Vermont modified broth (UVM) followed by 24 hour in FB. Samples were evaluated at four-hour intervals over a 48-hour enrichment process using DNA extraction and sequencing for each time-point. Resphera Insight and CosmosID analysis tools were employed for high-resolution profiling of 16S rRNA amplicon and whole genome shotgun datasets, respectively.