Options For R-CARD® Use

 

1. R-CARD® (3.5”x 4”) Inoculate with 1 mL of aqueous inoculum

•  Results indicate the number of target organisms in one mL of inoculum. This is the simplest when there are sufficient target organisms present (at least 10-100/mL)

Procedure: Prepare samples as usual and make a serial dilution if necessary. Wear a clean glove and lift the top portion (film) or use sterile forceps. Select dilutions of the sample to produce 10-100 colonies on the cards. Pipette 1 mL of the sample on the center of the card bottom. Cover with the film, and wait 1 minute to allow liquid to spread automatically. Place the inoculated R-CARD® (right side up) into an incubator preset at the preferred temperature, according to specific test protocol (SOP). Incubate for predetermined times and observe and record the results.

2. R-CARD® (3.5”x 4”) Filter the aqueous inoculum thru a 47mm, 0.45µm Micropore Membrane filter

• This is the most accurate approach when the precise number of target organisms is desired.

Procedure: Filter the aqueous sample ( properly diluted to result in 10-100 target organisms on the membrane filter) using a 47 mm, 0.45 µm filter following the standard procedure for water analysis. Lift the top film of the R-Card®. Use a sterile forceps to remove the membrane filter from the funnel. Place the membrane filter (right side up) onto the bottom piece of the R-Card®. Deposit 1mL of sterile (deionized or distilled) water on the membrane filter. Drop top film down and wait 1 minute to allow liquid to spread automatically. Incubate at the preferred temperature, according to specific test protocol. Incubate for predetermined times and observe and record the results. Count the number of target organism colonies (CFU’s) and multiply times the dilution factor to determine the actual number of target organisms/mL in the original undiluted sample. ( If you do not have the proper apparatus for membrane filtration, you may be interested in considering acquiring the Membrane Filtration Device Kit )

3. R-CARD® (4” x 4.5”) Inoculate with 3.0 mL of aqueous inoculum

• This is excellent when the number of target organisms is 10-300/100mL of aqueous inoculum.

Procedure: Prepare samples as usual and make a serial dilution if necessary. Wear a clean glove and lift the top portion (film) or use a sterile forceps. Select dilutions of the sample to produce 10-300 colonies (CFU) on the cards. Pipette 3 mL of the sample on the center of the card bottom. Cover with the top film, and wait 1 min to allow liquid to spread automatically. Place the inoculated R-CARD® (right side up) into an incubator preset at the preferred temperature, according to specific test protocol. Incubate for prescribed times and observe and record the results. This larger Card may allow you to satisfy your need for a somewhat larger sample size than the smaller R-CARD® (#1) at less time and expense that are involved in the Membrane Filter (#2) method.