VPE 511: Environment and Environmental Hygiene (2+1)

EXERCISE-11: DETERMINATION OF THE EFFICACY OF DISINFECTANT

Purpose

• The purpose of this protocol is to provide written guidelines to evaluate the efficacy of the disinfectants.

Aim

• This test procedure is applicable for evaluating the efficacy of all types of disinfectants.

Materials required

• Soyabean Casein Digest Agar medium (SCDA)
• Agar Plates
• Test tubes
• Inoculation loop
• Disinfectant to be tested
• Test organisms

Procedures

• Estimation of the percentage concentration
• Prepare different concentration of disinfectant like 1%, 2%, 3% , 4% and 5% with distilled water.
• Inoculate 1 ml of each microbial suspension having the concentration of 10⁶-10⁸ per ml into the prepared solution
• Wait for five minutes, then aseptically transfer 1 ml of the inoculated solution into two sterile petri plate.
• In the case of the bacterial suspension pour 20-25 ml of SCDA into the petri plate.
• Incubate SCDA plates in 30-35^o C

Results

• Examine the plate after 48 hours
• Find out the growth of the organism in the plate
• From the presence and absence of growth in different plates the efficacy of the disinfectant in percentage will be ascertained.