A microbial inhibitor screening test using Bacillus stearothermophilus var. calidolactis C953 as test micro-organism and being sufficiently sensitive to detect 4 ig Benzylpenicillin per milk and 100 ig sulfadimidine per milk shall be used. Commercial test kits are available and can be used if they have the required sensitivity for Benzylpencillin and sulfadimidine (1).
