How accurate is my spiral plater compared to my existing method?
SENSITIVITY AND REPRODUCIBILITY OF WASP – INTRODUCTION Traditional methods for counting viable microorganisms are labour intensive yet the standard plate count remains a widely used tool in many microbiology laboratories. The spiral plate method for the enumeration of organisms introduced considerable advantages over the standard plate count and has been shown to give comparable results. The technique was, however, limited in that it did not allow deposition of replicate samples without refilling the syringe and more importantly it had a lower sensitivity of 400 cfu/ml as a result of the 500 µl sample volume. METHODS All studies were carried out on a production WASP instrument. The WASP uses microprocessor-controlled stepper motors to automate the instrument and consequently allows the sample volume to be selected as 50, 100, 200 or 400 µl. Determination of dispensed volume Determination of dispensed volume was in accordance with BS7653: Part 3: 1993, Piston and/or plunger operated vol
