AUTHOR=Wittwer Marcel, Hammer Philipp, Runge Martin, Valentin-Weigand Peter, Neubauer Heinrich, Henning Klaus, Mertens-Scholz Katja TITLE=Inactivation Kinetics of Coxiella burnetii During High-Temperature Short-Time Pasteurization of Milk JOURNAL=Frontiers in Microbiology VOLUME=12 YEAR=2022 URL=https://www.frontiersin.org/articles/10.3389/fmicb.2021.753871 DOI=10.3389/fmicb.2021.753871 ISSN=1664-302X ABSTRACT=The Gram-negative, obligate intracellular bacterium Coxiella burnetii is the causative organism of the zoonosis Q fever and is known for its resistance toward various intra- and extracellular stressors. Infected ruminants such as cattle, sheep, and goats can shed the pathogen in their milk. Pasteurization of raw milk was introduced for the inactivation of C. burnetii and other milk-borne pathogens. Legal regulations for the pasteurization of milk are mostly based on recommendations of the Codex Alimentarius. As described there, C. burnetii is considered as the most heat-resistant non-spore-forming bacterial pathogen in milk and has to be reduced by at least 5 log10-steps during the pasteurization process. However, the corresponding inactivation data for C. burnetii originate from experiments performed more than 60 years ago. Recent scientific findings and the technological progress of modern pasteurization equipment indicate that C. burnetii is potentially more effectively inactivated during pasteurization than demanded in the Codex Alimentarius. In the present study, ultra-high heat-treated milk was inoculated with different C. burnetii field isolates and subsequently heat-treated in a pilot-plant pasteurizer. Kinetic inactivation data in terms of D- and z-values were determined and used for the calculation of heat-dependent log reduction. With regard to the mandatory 5 log10-step reduction of the pathogen, the efficacy of the established heat treatment regime was confirmed, and, in addition, a reduction of the pasteurization temperature seems feasible.