The Centers for Disease Control and Prevention has conducted investigations into outbreaks of listeriosis extending from 2014 onwards. Epidemiologic studies in 2017 and 2021 identified Queso Fresco and other cheeses as the vehicles of infection but the source was not identified. Intensive investigations were initiated in January 2024 after recent outbreaks the preceding month. Based on interviews, the Don Francisco brand was implicated, and the outbreak strain was identified in the plant operated by Rizo-Lopez Foods.
Whole genome sequencing assay demonstrated commonality among samples of Listeria monocytogenes isolated from patients and recovered from the plant. Health authorities in Hawaii isolated the same Listeria from patients and cheese produced by Rizo-Lopez Foods during January.
On February 6th, 2024, Rizo-Lopez Foods recalled all cheese and other dairy products and has ceased production pending further investigations and decontamination of their plant and equipment.