Some of the organs and secretions from Q fever infected cattle originally intended for human consumption were tested for their Coxiella content. In the cows, the udder and udder lymph nodes were found to contain over 75% of the exciters; the exciters were also found to a large extent in the milk, reaching levels of between 10(1) and 10(5) Inf. E/ml milk. On the other hand, other parts of the animal used as meat were less infected. Lymph nodes in the body contained 28%, liver, kidney, pancreas and lungs 25% and musculature (meat) 8%. Udder infections in cows can last for months or even years, but they persist only for a few weeks in sheep. Treatment and preservation methods used on the meat after the animals is slaughtered also decimate the exciters, thus decreasing any risk to the consumer. Infected milk also loses its capacity for infection when sufficiently pasteurised, though the problem of oral infection in fresh milk still exists. Tests on guinea pigs show that when they are fed fresh milk containing Coxiella the formation of blood antibodies can take place, and also infestation of the organs. Essential conditions for this can be found in the exciter content, the virulence of the exciters and a weak defence mechanism in the organism.