Laboratory and pilot-farm evaluation of cleaning and disinfection protocols for biofilms in livestock drinking water systems.

Persistent biofilms harboring pathogens can compromise drinking water quality in livestock housing, leading to animal health issues and reduced production. Microbial water quality can be maintained through various treatments and/or by cleaning and disinfecting drinking water systems to remove dirt and biofilms. However, despite routine monitoring of drinking water quality, biofilm persistence after treatment is often overlooked in practice. This study evaluated commonly used (cleaning and) disinfection protocols (peroxides, peracetic acid, chlorine dioxide, formic acid, chlorine, and enzymatic) for drinking water systems, both in vitro and in situ. Four selected three- or four-species communities were grown on polycarbonate and stainless-steel coupons in a stirred Centers for Disease Control (CDC) biofilm reactor. The in situ study was conducted on a pilot broiler farm during four consecutive six-week production cycles, with both water and biofilm samples collected during each cycle. Our in vitro study showed that the disinfectants reduced multispecies viable biofilm cells, but the effects varied with microbial composition. The in situ results showed little effect of the cleaning and disinfection protocols. Consequently, targeted intervention strategies, supported by regular monitoring of water quality and biofilm presence, are essential for making treatment decisions to minimize the risk of water contamination.