Detection of residual penicillins in milk by using a Bacillus stearothermophilus disk assay
Ouderkirk, L.A.
Journal - Association of Official Analytical Chemists 60(5): 1116-1118
1977
ISSN/ISBN: 0004-5756 PMID: 893331 Document Number: 123914
A paper disk method based on a procedure described by the International Dairy Federation is presented for the detection of 4 .beta.-lactam antibiotics (penicillin G, ampicillin, cephapirin and cloxacillin) in whole milk. B. stearothermophilus var. calidolactis, prepared as a stable spore suspension, was used as the test organism. Levels of 0.005 unit penicillin G/ml, 0.005 .mu.g ampicillin or cephapirin/ml and 0.05 .mu.g cloxacillin/ml were readily detected in whole milk. Results were produced in 3-4 h. The method offers several advantages, including greater simplicity, sensitivity and rapidity over methods now commonly used to detect residual levels of these drugs in milk.