Question

What are the ranges of colonies counts that are acceptable on a plate for a spread plate and pour plate? Why are they different? for a​

Answer 1

Each (both large and small) colony is carefully counted (using magnifying colony counter if needed). Each colony represents a “colony-forming unit” (CFU). For accurate counts, the optimum count should be within the range of 30-300 colonies/plate. To insure a countable plate a series of dilutions should be plated.