PCA + TTC + Neutralizing / VRBL Agar + Neutralizing dipslide is a ready-to-use device with two different media coated onto a plastic support used for the microbial monitoring of surfaces and liquids even in the presence of residues of disinfectants. The selective medium allows the isolation and enumeration of coliform bacteria. The other medium is used to obtain the total bacterial count.

TEST PROCEDURE

1. Take a slide from the refrigerator and leave it at ambient temperature for about 5 minutes.
2. Unscrew and extract the slide from its cylindrical container. Avoid any contact with the agar surface.
3. For surface monitoring, flex the cap forming a 90° angle and press each side of the slide firmly against the surface to be examined for 10 seconds. Alternatively, use a swab for sampling the area, afterwards roll the swab gently over the agar surface. For examination of liquids, hold the slide by the cap and immerse it completely into the test fluid.
4. Reinsert the slide into its tube, screw it tight and incubate for 24 h at 30 ± 1°C or 37 ± 1°C, depending on the organisms and materials investigated (e.g. in case of milk and milk products, the temperature of incubation is 30°C). Record the count on VRBL Agar + Neutralizing prior to continue incubation at 30 ± 1°C for other 48 h.

RESULTS INTERPRETATION

Count the total number of colonies on PCA + TTC + Neutralizing (Side 1) to obtain the total bacterial count. Coliforms rapidly ferment lactose forming pink to red or purple colonies (with or without precipitation haloes) on VRBL Agar + Neutralizing (Side 2).

APPEARANCE

Side 1. Slightly opalescent, light amber.

Side 2. Very slightly to slightly opalescent, reddish-purple.

STORAGE CONDITIONS

10-25°C away from light, until the expiry date on the label. Eliminate if signs of deterioration or contamination are evident.

SHELF LIFE

9 months