b. When counts of duplicate plates fall within and without the 25-250 colony range, use only those counts that fall within this range.
2. All plates with fewer than 25 CFU. When plates from both dilutions yield fewer than 25 CFU each, record actual plate count but recount but recount but record the count as less than 25 x 1/d When d is the dilution factor for the dilution from which the first counts were obtained.