Manufacturing traditional Balkan Kajmak: Strategies to mitigate Listeria monocytogenes recontamination

From 2020 to 2022, an outbreak of listeriosis occurred in Austria, resulting in ten cases, three of which proved fatal. The outbreak was traced to a traditional southern European dairy product known as Kajmak, a lightly salted cream product. The subsequent sequencing of clinical and food-related isolates with clonal complex (CC)1 clonal type (CT) 6568 led to the identification of the outbreak's origin. CT6568 is classified under CC1, which exhibits notable diversification among human isolates, with 14 distinct CTs identified between 2020 and 2022. The clientele of the cheese factory primarily comprised local Balkan restaurants, delicatessen counters, and small bakeries. The existing self-monitoring system and the Hazard Analysis and Critical Control Points (HACCP) program did not meet the requisite standard of adequacy. Listeria monocytogenes was identified in the production and ripening room, indicating potential recontamination of Kajmak during the manual filling and ripening process. The highly perishable product in question was also incorrectly labeled with a best-before date (>21 days) instead of a use-by date. Furthermore, crucial labeling information for customers, such as the necessity of strict refrigeration at 4 °C, was absent. The outbreak was likely precipitated by the discontinuous production of Kajmak, which resulted in inadequate environmental hygiene. The retrospective report on the outbreak highlights the lack of risk analysis in research conducted on food safety risks associated with small-scale production of traditional foods. It is essential that manufacturers align their understanding with the principles of the HACCP concept and effective self-monitoring systems.