Using whole genome sequencing (WGS), the U.S. Centers for Disease Control and Prevention (CDC), the U.S. Food and Drug Administration (FDA), and public health and regulatory officials in several states recently solved a multistate foodborne illness outbreak investigation that has been ongoing since 2014, with the most recent illnesses being reported in December 2023.
CDC first investigated this outbreak of illnesses caused by Listeria monocytogenes in 2017, and again in 2021. Epidemiologic evidence in previous investigations identified queso fresco and other similar cheeses as a potential source of the outbreak, but there was not enough information to identify a specific brand. CDC reopened the investigation in January 2024 after new illnesses were reported in December 2023 and the outbreak strain was found in a cheese sample from Rizo-López Foods in Hawaii.