Coxiella burnetii implications for food safety

Q fever is a zoonosis found worldwide, with the exception of New Zealand, caused by Coxiella burnetii, an obligate intracellular bacterium that is considered enzootic in ruminants and ubiquitous in the environment. C. burnetii is shed in parturient products, urine, feces and it is also shed in the milk of cattle, sheep and goats. C. burnetii is considered a microbiological hazard associated with the consumption of unpasteurized milk products. This bacterium is frequently detected in dairy products, including cheese and yogurt, by PCR testing. The risks from C. burnetii through consumption of unpasteurized milk and milk products are not negligible, but they are lower in comparison to transmission via inhalation of aerosols from parturient products and livestock contact. There is epidemiological evidence that a small proportion of cases in the developed world may arise from drinking unpasteurized milk, but much less evidence exists for consuming other milk products, such as cheese. Several outbreaks have been associated with the consumption of unpasteurized dairy products. Although, the pathogenesis of Q fever after ingestion of C. burnetii by humans is poorly understood, the public health risk of raw milk consumption should not be underestimated. In recent years, raw milk consumption has increased in popularity in the United States, which increases the risk of raw milk associated foodborne illnesses. The risk of Q fever associated with the consumption of meat products is unknown. However, exposure to contaminated carcasses has been described as an occupational hazard of slaughterhouse workers, due to the manipulation of carcasses that are infected with C. burnetii. The transmission of disease is most likely due to direct contact or aerosolization of infected particles. Q fever prevention efforts should focus on minimizing contact with animals that may be shedding C. burnetii and their contaminated environment, especially for those at higher risk (i.e., pregnant women, young children, elderly people, and immunocompromised individuals).