Inoculation of fabrics
A coliform suspension of 250 mL was pipetted onto sterile glass
Petri dishes. Three types of fabric (100% cotton, blended cotton, and
silk) were selected based on their ability to absorb the coliform
suspension. Each fabric was cut into squares of 2.5 2.5 cm and
then sterilized by autoclave. Sterile tweezers were used to place
each piece of fabric onto 1 drop of the 250 mL coliform suspension.
One drop of the coliform suspensionwas not covered with fabric to
serve as a control. The cell suspension was always in contact with
the fabric square. The Petri dishes were covered for 1 hour. Then the
fabrics were transferred into new sterile Petri dishes using sterilized
tweezers. This approach allowed the investigators to determine
the number of bacteria that did not adhere to the fabric square
and remained on the Petri dish surface. The fabrics were exposed to
3 environmental conditions: 25C incubation in the dark (no light
exposure), 37C incubation in the dark (no light exposure), and
exposure to sunlight at room temperature, approximately 25C.
Fabrics stored in the dark were placed into incubators at the proper
temperature for the duration of the experiment, whereas fabrics
exposed to sunlight were placed on a window sill and received at
least 10 hours of exposure to sunlight each day. The experiment
was performed in 4 separate trials