Abstract
SUMMARY: Penicillinase preparations strong enough to destroy all the penicillin in 1 hr. or less at room temperature should be used in carrying out sterility tests on solid penicillin. Otherwise, penicillin-sensitive contaminants may be killed by the penicillin before it is destroyed and samples containing them will be sterile by the test. A convenient unit of penicillinase is the quantity which will destroy 100 units of penicillin in 1 ml. in 1 hr. at room temperature (24°).