A new suspect: Listeria monocytogenes outbreak linked to pasteurised plant-based beverages, Canada, 2024

In Canada in 2024, an outbreak of Listeria monocytogenes occurred, linked to pasteurised plant-based dairy alternative beverage products. The outbreak involved 20 confirmed cases (age range: 7-89 years; 13 females, seven males; 14 having underlying medical conditions) and resulted in three deaths. All cases were infected with the same genetic strain of L. monocytogenes. Nineteen of the 20 outbreak-confirmed cases reported consuming the same brand of plant-based beverage product prior to illness onset, and the outbreak strain was found in six open leftover plant-based beverage samples collected from the homes of six outbreak-confirmed cases. All L. monocytogenes-positive food samples were produced at a single manufacturing facility in Ontario, Canada on the same production line. The outbreak strain was confirmed in post-pasteurisation processing areas at the manufacturing facility. However, the source of contamination was not determined. Leftover case-food sample collection by local public health authorities and laboratory testing were instrumental in the timely identification of the outbreak source - a food recall warning was issued within 2 weeks of initial case-food WGS match. Manufacturer adherence to applicable requirements regarding L. monocytogenes in ready-to-eat foods continues to be critical to prevent Listeria contamination and subsequent illnesses and/or deaths.