Technical Information

USER QUALITY CONTROL PROCEDURES

Two levels of QC are routinely applicable to the BART biodetectors to ensure:

(1) sterility of the inner test vial which holds the ball, medium pellet and the water sample;
(2) reliability of the medium pellet to allow the appropriate forms of activities and reactions for selected strains of bacteria.

The selection of these two principal QC procedures is based on the critical need for the inner test vial to be free from contamination. This could cause interferences with the performance characteristics of the test and the medium performing in an appropriate manner. In performing these QC procedures, it is assumed that the person undertaking this procedure has an adequate understanding of basic aseptic procedures and the necessary skills to safely culture bacteria.

Confirmation of the sterility of the BART Biodetectors

In the normal event of the confirmation of sterility, there is a change in the characteristics of the liquid medium forming in the test vial. The test vial can be considered to be Essentially sterile where the liquid remains crystal clear as the nutrient pellet gradually dissolves and forms into a diffusion front which moves up and eventually dissolves completely to form the culture medium. For each BART biodetector, a characterization of medium diffusion of the test vial is given below, along with test methods describing the suitability of selective medium of each type of biodetector.

Sterility QC on the Inner Test Vial

Aseptically remove the inner test vial of the BART by removing the screw cap on the outer vial and lifting out the inner test vial. Screw the cap back onto the outer vial. A QC test can now be performed on the inner vial. The following directions are common to all BART biodetectors and the procedure should be performed on each of them.

Aseptically add 15 ml of sterile distilled (which has been kept at room temperature) to the vial. Do not use non-sterilized distilled or deionized water for these tests since the incumbent bacterial population may be sufficient to trigger a reaction in the test vial. Stand the test vial up at room temperature (22 to 24^oC) and observe for twelve days. If the test vial is sterile there should be no evidence of bacterial activity or reactions. If evidence is found that the test vial was contaminated, this could have been an isolated event. Repeat the procedure in triplicate. Should a duplicate result suggesting contamination, please contact the QC dept. at (306) 585-1762 or by fax at (306) 585-3000.

Below is a description of the typical events that occur as the dried medium pellet dissolves and diffuses up into the water column. It is based upon the standard QC procedures discussed above. There are two events to determine. First, the form in which the medium pellet diffuses up into the water. This gives a good indication as to the acceptability of the medium. Second, the clarity with which this happens indicates whether or not there has been some microbial contamination. If contamination has occurred from whatever source, clouding, slime formation, abnormal color shifts and gasses are possible consequences and the test vial would be deemed to have failed the test. It should be remembered that if the water used for this test contained a high concentration of various salts, it is possible for some of these reactions to occur. It must therefore be remembered that only sterile (distilled or deionized) water should be used in these QC tests. Additional tables are used to describe the initial diffusion patterns that should occur in these QC tests and also the most common form of expression of bacterial contamination.

A successful QC test would have the typical characteristics reported for the basal zone and the column. There should be no evidence of microbial contamination that would usually be seen in the form described in the "contamination" column. Every effort is made by Droycon Bioconcepts Inc. to produce a sterile product and routine QC practices are undertaken to ensure that the product has a satisfactory quality. Users may request the "Certificate of Analysis" issued for every batch of BART produced.

Assurance of Status of Crystallized Medium by Visual Inspection

To do this test effectively, the BART inner test vial should be removed from the outer test vial and held upside down at an angle which allows the convenient observation of the dried medium pellet through the conical base of the test vial. Note that there is a vertical plastic peg in the middle of the cone which may, or may not, be observable depending upon the test type. After observing the medium pellet through the cone, any medium deposited on the side-walls of the inner test vial should be examined. These observations should then be compared to the standard (acceptable) range of characteristics listed below for each BART product. Where the crystallized medium falls outside the described characteristics, it may be unacceptable.

It is recommended that, to view the base of the test vial, the tube be held with the basal cone facing directly towards the observer. It is best to view this using diffuse light against a neutral background. After viewing the base, examine the lower walls just above the basal cone for any medium deposits. Some of the media will coat the lower walls up to a height of 5mm above the cone. All BART products are examined for splattering of dried medium on the sidewalls of the inner test vial. If there are any splatter particles of greater than 1 mm diameter or a number positioned to disturb the view through the test vials, the tube is rejected (second grade). These seconds are still effective for conducting the tests. Tubes are rejected where there is an acceptably large amount of splatter (>1% of wall area) which affects the viewing of any reaction, or there are fractures in the polystyrene wall of the vials exceeding 5 mm in length and/or have penetrated through the vial wall.

EXPIRY DATE QC

The BART test products are protected from degeneration during storage by the use of an aluminum foil package as a moisture barrier, aseptic manufacturing procedures, crystallization of the dried medium pellet, and post-production QC procedures. Presently the recommended expiry date is set at three years after packaging. There remains however a need to remain confident that the stored BART test hasn't degenerated in any manner that could affect its performance. Recommended QC test procedures for the various BART tests are described above. One feature of the BART test products to be remembered is that they are extremely sensitive to the presence of bacteria in the sample used. In the event of a QC procedure, it is therefore essential to use sterilized (distilled or deionized) water for the test and to use aseptic procedures. It is important to insure that the water is sterilized (commonly by steam sterilization using an autoclave or pressure cooker). It has been found that regular distilled or deionized water commonly do contain an active population of bacteria which is sufficiently large to cause activities and reactions to occur in the BART under test. In the Droycon Bioconcepts Inc. QC laboratory, commercially available distilled and deionized water frequently generate reactions with a time lag (days of delay to reaction) of 2 to 4 days. The use of such nonsterile waters is therefore likely to give unacceptable results. To ensure that the BART test is still suitable for use as a test procedure, the following steps need to be followed:

1. Assurance of the status of crystallized medium by visual inspection.
2.Addition of sterile water to the BART inner test vial and determine forms of diffusion from the basal nutrient medium pellet in the base.
3. Determine whether there has been any microbial activity arising from contamination of the BART test during storage. This is done through looking for clouding, slime formation abnormal color generation and/or gas bubble formation during the test procedure listed as 2 above.

All of the BART test products are subjected to this QC procedure to be assured that there has not been any deterioration of the products over time.