Detection of Residual Antibiotics in Food (I)

Abstract

Experimental studies on the detection of residual antibiotics in tissues and on its presumptive classification were made by a simple pulp disk zone inhibition method, by use of Bacillus stearothermophilus var B. calidolactis C-953, Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538 P. Sarcinalutea ATCC 9341, Escherichia coli NIHJ, and Escherichia coli NIHJ TC resistant strains.Results obtained are summarized as follows:1) It was confirmed that these six strains had different response patterns of growth inhibition to the penicillin (PC), tetracycline (TC), chloramphenicol (CM), erythromycin (EM), novobiocin (NB) and cycloserine (CS). Contrary to this, streptomycin (SM) and fradiomycin (FM) showed quite resembling inhibition patterns to them, and could not be discriminated.2) Drugs which might have a chance of migrating into food, such as benzalkonium chloride, hydrogen peroxide, synthetic detergent Lipon F (commercial name) 2- (2-furyl) -3- (5-nitro-2-furyl) acrylamide (AF-2) and BHA were found to show their specific inhibition patterns, and these patterns could be easily differentiated from those of the antibiotics ones.3) SM, TC and CM were quite stable in mutton emulsion, while they were kept at 30°C for 7 days. On the contrary rapid degradation was observed on PC.4) Presumptive classification of unknown substance, contained in beef which had been submitted by a consumer for the examination of foreign substances, showed anti-microbial activity, and the substance was presumed to be CM from its inhibition pattern.