• A colony counter is an instrument
used to count colonies of bacteria or
other microorganisms growing on an
• An instrument designed to
conveniently count or assist
counting colonies of microorganisms
on a plate containing a gelled growth
• One variety uses a pencil-like rod with a metal
tip, which is connected by an electrical
connection to the gelled growth medium; when
touched to a colony on the plate, the completion
of the electrical circuit causes an increment of 1
unit on the readout of the colony counter.
• Early counters were merely
lighted surfaces on which the
plate was placed, with the
colonies marked off with a felttipped pen on the outer
surface of the plate while the
operator kept the count
• More recent counters attempt
to count the colonies
electronically, by identifying
individual areas of dark and
light according to automatic or
user-set thresholds, and
counting the resulting
1. Place the
on the colony
2. Count a Petri-dish by clicking the count button
on the software.
• 3.The results will be displayed indicating the
number of colonies.
The Recent Colony Counter
• The automatic colony counter has the ability to
separate the image of combined colonies for the
user to magnify each colony.
• The recent colony counter is connected to a PC.