Chemical Destruction of Mycobacterium bovis in Milk

The tuberculocidal activity of phenol and 1-Stroke Environ was tested using five Mycobacterium bovis strains added separately to five samples of untreated cows milk. The tuberculocidal activity of each disinfectant was significantly improved (P = .005) by increasing exposure temperature from 4 to 23 C or by increasing exposure time from 1 to 6 h or by increasing disinfectant concentrations two-fold. Environ diluted 1:8 or phenol diluted 1:32 killed each of the five strains of M. bovis suspended in untreated milk (6 mg/ml) during a 6-h exposure at 23 C. Either disinfectant could be used to destroy M. bovis in unsalable milk from tuberculous cows scheduled for slaughter.