BioLumix Microbial Limit Vial (MC)
The Microbial Limit vial is used to test primarily Personal Care, Cosmetic and over the counter Pharmaceutical (OTC) products for microbial content (contamination). Each of these types of products may have preservatives in their composition and the Microbial Limit vial helps to neutralize the inhibition of microbial growth that many preservatives provide. Neutralization of the preservative allows for a proper evaluation of whetheror not the product has contaminants. Often the contaminating bacteria in the product while in the presence of the preservative remain “injured” and unable to replicate. Thelack of replication might be interpreted as the lack of contamination.
The Microbial Limit vial’s sensor detects production of CO2 by microorganisms, based upon the principle that CO2 is a universal metabolite produced by all microorganisms. The disposable vial contains a transparent solid sensor located at the bottom which changes its optical properties whenever CO2 diffuses into it. Only gases can penetrate the sensor; blocking liquids, microorganisms, and particulate matter. Consequently, the optical readings are not masked by the sample. CO2 generated by bacterial metabolism in the liquid medium diffuses into the sensor and interacts with an indicator reagent to provide an indication of the presence of the carbon dioxide.
The Microbial Limit vial is used to test primarily Personal Care, Cosmetic and over the counter Pharmaceutical (OTC) products for microbial content (contamination). Each of these types of products may have preservatives in their composition and the Microbial Limit vial helps to neutralize the inhibition of microbial growth that many preservatives provide. Neutralization of the preservative allows for a proper evaluation of whether or not the product has contaminants. Often the contaminating bacteria in the product while in the presence of the preservative remain “injured” and unable to replicate. The lack of replication might be interpreted as the lack of contamination.
The first step of the assay is to perform a 1:10 dilution of the product in neutralizing broth such as D/E (Dey/Engley) broth, Letheen Broth, or TAT (Tryptone-Azolectin-Tween) Broth. There after 1.0-0.1 ml of the sample is added to the Microbial Limit vial. The Microbial Limit vial contains the neutralizers that inhibit many common preservatives and this neutralization event helps the customer to correctly measure the presence of contaminating organisms.
Examples of Growth Curves Using the Microbial Limit Vial:
In the curves shown below in the Figure, there is an example of both a positive curve and a negative curve. The bacterium used was Pseudomonas aeruginosa.
The BioLumix Microbial Limit vial was specifically designed to be used in complying with USP. Due to the fact the Microbial Limit vial has both Lecithin and Tween in its media composition helps allow for neutralization of the preservative in the sample to be maintained during the assay for viable organisms. Thus, this vial is useful to the customer that has already determined the amount of neutralizing buffer and its content of neutralizer to be used when the product sample is first prepared in diluent. Together the use of the correct neutralizer and the use of the BioLumix Microbial Limit vial helps ensure an accurate assay for the replicating organisms.
Table 1 summarizes the types of Products that customers test in the BioLumix Microbial Limit vial to measure the presence of organisms.
The versatility of the BioLumix Microbial Limit vial includes the ability to support growth of most aerobic bacteria, many yeast and some mold organisms. In most cases YMC vial is used for the detection of yeast and molds. The BioLumix Microbial Limit vial can be used for determination of microbial content (contamination), for use in suitability studies that test whether a product can support growth of microorganisms, and in Preservative Efficacy Studies (PET analysis) that is used for cosmetic products. The BioLumix Microbial Limit vial can also be used by customers whose products include Dietary Supplements and Nutraceutical products for which preservatives (natural or chemical) are also added. Supplement products with natural preservatives also need to be neutralized and tested for their ability to support microbial growth.
