| 
      
        | Sample | Dilution | Concentration of tetracycline (m/ml) | No. of Colony | No. of Bacteria/ml |  
        | 1 | 10-4
          10-4
          10-4 | 30
          60
          100 | 33
          11
          3 | 33×10-4
          11×10-4
          3×10-4 |  
        | 2 | 10-4
          10-4
          10-4 | 30
          60
          100 | 53
          24
          6 | 53×10-4
          24×10-4
          6×10-4 |  
        | 3 | 10-4
          10-4
          10-4 | 30
          60
          100 | 91
          33
          11 | 91×10-4
          33×10-4
          11×10-4 |  
        | 4 | 10-4
          10-4
          10-4 | 30
          60
          100 | 102
          43
          13 | 102×10-4
          43×10-4
          13×10-4 |  |