SRK
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Catalog excerpts

SRK - Easy to Use, Easy to Transport How to Use Guide 1. Identify the site or surface to be sampled. When sampling flat surfaces it is advisable to use a sterile Square Sampling Template to define a specified area or sample size. 10 x 10cm and 4 x 5cm sampling templates are available separately from Copan. 2. Unscrew the SRK swab cap and lift the swab above the solution in the tube. Press the tip of the swab against the wall of the tube to remove excess liquid. 3. When sampling flat surfaces using a square template, place the tip of the swab on the surface to be sampled in the inside top left corner of the template and sweep from left to right. Slowly moving down the length of the template to make a complete left to right sweep of the area designated by the template. Rotate the swab between the thumb and forefinger during the sweeping action to maximize the uptake of surface material. 4. A second complete sweep is made inside the square template at right angles to the first sweep. See photo which demonstrates the bi-directional sampling action. 5. When sampling is complete return the swab to the original tube of solution from where it came or in the case of Combo Sets place the swab in the accompanying tube of Buffered Peptone Water or Letheen Broth. Make sure the cap is properly tightened. 6. Write specific information on the SRK tube label to identify the site or surface under investigation. 7. Transport samples to the laboratory for analysis as soon as possible, preferably within 4 hours, in a cool box at 1 - 4°C. Samples can be refrigerated at 2 - 8°C for up to 24 hours before laboratory analysis. Processing the SRK sample 1. In the laboratory vortex mix the swab thoroughly in the solution provided in the tube to release sample material from the swab and make an even suspension. blue lines are for illustrative purpose 2. Removed measured aliquots of the solution and perform a Surface Plate Count or Pour Plate Count. For Surface Plate Counts inoculate aliquots directly onto the surface of suitable plate count agar and spread the sample evenly using a sterile spreader. For Pour Plate Counts place an aliquot into a sterile Petri dish and mix with 15 or 20ml of melted agar (maintained at approximately 45°C) then allow the agar to cool and solidify. 3. If the concentration of organisms in the sample is expected to be high, serial ten-fold dilutions of the solution inside the SRK tube can be performed and the ten-fold dilutions can be cultured. Formula for calculation of the number of cfu per cm2 of the surface investigated: NxF x D, where N = the number of cfu A in 1ml dilution liquid (rinse solution or broth) = the amount (ml) of dilution fluid (rinse solution or broth in the tube) A = the surface investigated (cm2) D = the reciprocal of the dilution used

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