Commonly used disinfectants can vary widely in efficacy
Commonly used disinfectants can have substantially different efficacy and should be tested against the pathogen of concern — and under the conditions of use — before they’re used on swine farms, caution investigators from the University of Minnesota, St. Paul.1
In their study, they tested three disinfectants commonly used on Minnesota swine farms against Senecavirus A (SVA) — household bleach, a phenolic disinfectant and a quaternary ammonium-aldehyde disinfectant.
The disinfectants were tested on five different surfaces — aluminum, stainless steel, rubber, cement and plastic — at two different temperatures. The SVA used was a contemporary strain, said Azad Singh, MVSc, and colleagues in the 2017 March and April issue of the Journal of Swine Health and Production.
Common bleach was most effective, they reported. At about 25° C (77° F), bleach at a 1:20 dilution inactivated ≥ 99.99% of the virus within 10 to 15 minutes on aluminum, rubber and plastic.
On stainless steel and cured cement, it inactivated 99.97% and 99.98% of the virus, respectively. At 4° C (39.2° F), bleach inactivated ≥ 99.99% of the virus within 5 to 15 minutes on all surfaces except rubber, where it inactivated 99.91% after 15 minutes, they report.
In contrast, the phenolic disinfectant used at the manufacturer’s recommended concentration inactivated ≤ 82.41% of the virus at either temperature and on any surface, even after a 60-minute contact time.
Results for the quaternary ammonium disinfectant were intermediate: It inactivated 78.12% to 99.81% of the virus within 60 minutes at both temperatures and on all surfaces, they say.
The investigators pointed out their experiments were performed without added organic matter, such as manure, which is inevitable on swine farms and reduces disinfectant efficacy. As a result, “the cleaning of the facilities before the application of disinfectants is a prerequisite,” they said.
The investigators noted that because they used only dry surfaces in their study, they couldn’t determine whether results would be the same on the wet surfaces common in swine barns.
Even though 4° C (39.2° F) doesn’t represent conditions inside a swine barn, it does reflect outside conditions, especially during Midwestern winters, they added.
 Singh A, et al. Efficacy of three disinfectants against Senecavirus A on five surfaces and at two temperatures. J Swine Health Prod. 2017;25(2):64-68.