Methods & Materials
Since both cleaners
advertises that they would not leave germs (such as bacteria) on sponges
after use; this property was tested. However in the case that they both
would test positive for this property another more accurate method would
be used to find out which cleaner would kill more bacteria under the same
conditions.
To see
if the cleaners would not leave bacteria on sponges a unique method was
used. Twos sponges were taken and each was saturated with a different cleaner.
Then Escherichia coli was applied to the sponges using sterile cotton swabs.
After an hour another sterile cotton swab was used to take samples from
each sponge and transfer the each sample to a different petri dish
which contained agar (agar was obtained in ready to use form and was poured
in the petri dish at an angle to maintain sterilization). The two petri
dishes were then incubated for 24 hours and then taken out and the results
were then taken.
This method tested the cleaners
effectiveness on a surface. However to test how effective these cleaners
are in stopping the spread (growth) of Escherichia Coli another method
was used. In this method agar was obtained in solid form and then liquefied
in a hot water bath. Then 10 sterile petri dishes were divided (using a
permanent marker) into 4 sections. Then Each petri dish was opened at an
angle, to maintain sterility and agar was poured in from the bottle just
enough to cover the bottom of the petri dish. These petri dishes were then
placed in the refrigerator so that the agar may turn in to a gelatin like
substance.
Escherichia
Coli was obtained in liquid sterile form in a test tube. Then a sterile
cotton swab was used to transfer the Escherichia Coli from the test-tube
on to the petri dish. For this to be done the petri dishes (which were
prepared with agar earlier) were opened at an angle to maintain sterility,
and when painted the first time with Escherichia Coli, they were then rotated
at a 90° angle and painted again with escherichia Coli to make sure
that every spot is covered. Then these petri dishes were once again placed
into the refrigerator.
Now a 20% concentration of
Palmolive and Comet cleaner was made. Each new solution was constantly
stirred because these cleaners did not dilute well with water. Then ¼
inch sterile filter paper disks were prepared. These disks were then dipped
into the solution (either comet or Palmolive 20% solutions) and then placed
in the petri dish in one of the 4 sections (see Figure 1). Thus each petri
dish had two disks dipped into Palmolive solution, and two disks dipped
into comet solution to total 8 petri dishes. 2 petri dishes were prepared
with blank disks to serve as the control. All these petri dishes were than
incubated for 24 hours. They were then taken out and the results were taken.