Abstract
When ice is prepared from service water containing chlorotetracyline (CTC) with which to preserve fresh fish, antibacteriolytic activity of CTC is not found so stable as expected to be. Bioassay of CTC by Koholer pad-plate method modified from Grady's has confirmed that the activity of CTC resolved in service water is lowered from 5 ppm to 1. 5 ppm in an hour, while actithat in distilled water remains almost the same in the lapse of time (Ttable 1). A possible explanation of this is that the CTC activity is likely affected by Cl2 present in the service water as well as by the concentration of pH.
When acidified with citric acid, however, the service water has been turned out to be capable of keeping the CTC activity fairly stable. A report on the role of citric acid in this regard is under preparation.
