Procedure for Surface Monitoring of Equipment by Swab


Title : Procedure for Surface Monitoring of Equipment by Swab

Department : Quality Control-Microbiology


  • To lay down a procedure for surface monitoring of equipment by swab.
  • This SOP is applicable for surface monitoring of equipment by swab in microbiology laboratory.
  • Officer / Executive-QCM – responsible for Implementation of SOP.
  • Manager – Quality Control

          Preparation of swab before sampling operation:

  • Take sterile cotton swabs. Remove the tube containing swab from the poly pack and take out the swab.
  • Now dip the swab in 1 ml of 0.9% normal saline solution taken in a swab tube. Prepare similarly the necessary amount of swab tubes as per the sampling locations and autoclave all swabs at 1210C for 15 minutes at 15 psi pressure in a glass beaker.
  • Cool all the swab tubes in the beaker and store in a BOD incubator at 200C-250C such that the beaker is covered with aluminum foil. Now the sterile swabs are checked before subjecting operation.
  • Mark the swab tubes with the respective sampling locations with the help of marker pen prior to sampling operation.
  • Monitoring Procedure by swab:
  • Wear sterile gowns and enter the sterile area for surface monitoring by swab as per SOP of Entry in the sterile area.
  •  Transfer the cotton swabs to sterile area through cleaned pass box with UV in “ON” position or through airlock room.
  • Monitor the required equipment or sterile gown surface by swabbing an area on 5X5 cm in one direction. Follow the figure.






Figure 1 5X5 cm SS template

  • Clean the swabbed areas with 0.22 µ filtered 70% IPA solution and allow it to dry.
  •   Replace the swab inside the sterile swab tube immediately. Repeat similar swabbing operations for all sampling locations. After swabbing operations are over, bring all the tubes containing swabs dipped in normal saline to the microbiology laboratory and transfer to the LAF for further testing.
  • Now shake the normal saline of each tube reciprocally in such a way that any particles stuck on the swab surface should get dispersed properly in the normal Saline.
  •   Now remove the swab gently under LAF and pour the 1ml normal saline on the sterile Petri plate marked with sampling location with permanent marker pen. Pour gently approx 15-20 ml of autoclaved SCDA media on the plate and rotate the plate anticlockwise and clockwise direction in order to mix the contents. Proceed similarly for all other swab sampled tubes.
  • Allow the plates to solidify under LAF and after solidification transfer all the solidified   plates representing each swabbed sample location for incubation in inverted position in a BOD incubator at 200C – 250C for 5days and then incubated laboratory incubator at 300C – 350C for 2 days .
  • After incubation period completed , examine all Petri plates under colony counter and count the number of colonies for each sampled area and note the readings in a proper authorized format.
  • Frequency: – during every batch manufacturing in eye/ ear drop and once in a month in other sections.
  • Limit for grade A   <1
  •          ABBREVIATION

SOP      –  Standard operating procedure

QC        –  Quality Control

  •     FORMAT



Sr. No. Copy No. Department
Quality Assurance
Quality Control-Microbiology