Table 4.

Decimal reductiona of the numbers of different microbial parameters after pasteurization of sewage

Experiment no.Decimal reduction of the no. of:
E. colib CFUE. coli O157:H7c CFUSomatic coliphages (PFU)Phages infecting O157:H7 (PFU)Phages infecting O157:H7 and carrying the Stx2 gene (MPN)
1>4.2>4.50.50.3>0.4, <0.6d
2>4.1>4.60.70.6>0.3, <0.8
3>4.0>4.40.60.4>0.3, <0.6
  • a Reduction calculated as the decrease in log units.

  • b Naturally occurring E. coli.

  • c Seeded E. coli O157:H7.

  • d Decimal reduction was between the indicated values. When the result of one of the triplicates of one of the volumes was missing, the inactivation was considered to be between the MPN values calculated considering the missing value as positive or negative.