Should the Legionella positivity rate of all samples collected from a potable water system be the primary consideration for disinfecting an ice machine?

The focus on whether the Legionella positivity rate of all samples collected from a potable water system should be the primary consideration for disinfecting an ice machine highlights the complexity of Legionella management. While the positivity rate can provide valuable information about the presence of Legionella bacteria, it is not the sole determinant for deciding on disinfection.

Disinfection decisions should be based on a comprehensive risk assessment that includes not just the positivity rate, but also factors such as the concentration of Legionella present, the water temperature, the design and maintenance of the potable water system, and the vulnerability of the population using the ice machine. For instance, even with a low positivity rate, if there are underlying factors such as poor maintenance or elevated water temperatures, the risk may still be significant. Conversely, a high positivity rate does not automatically necessitate disinfection if there are effective risk mitigation strategies in place.

In summary, while the positivity rate of samples is an important factor to consider, relying solely on it without looking at the broader context could lead to inadequate evaluations and responses to Legionella risks. Therefore, other aspects of water management and exposure risk should be taken into account when deciding to disinfect an ice machine.