TAC: Total Aerobic Count Vial

The Total Aerobic Count 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 placed above the sensor, diffuses into the sensor and interacts with an indicator reagent to provide an indication of the presence of the carbon dioxide. The vial utilizes a nutritious non selective medium.

CC: Coliform Vial

The Coliform vial is a membrane vial (a membrane filter is used to separates the sample containing area where microorganisms may be present, from the reading zone where detections occur), monitoring a change in color due to a pH shift as coliform bacteria ferment lactose in the presence of a highly selective media.

ENT: Enterobacteriaceae Vial

The Enterobacteriaceae vial is a membrane vial (a membrane filter is used to separates the sample containing area where microorganisms may be present, from the reading zone where detections occur), monitoring a change in color due to a pH shift as Enterobacteriaceae organisms ferment glucose in the presence of a highly selective media.

YM: Yeast and Mold Vial

The Yeast and Mold vial’s sensor detects production of CO2 by all yeast and molds. 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 microbial metabolism in the liquid medium placed above the sensor, diffuses into the sensor and interacts with an indicator reagent to provide an indication of the presence of the carbon dioxide. The medium relays on the utilization of glucose, with a pH=6.0 and contains inhibitors against bacterial growth.

GN: Gram Negative Vial

The Gram Negative vial is a membrane vial, monitoring the utilization of a unique fluorescent dye in the presence of selective media that inhibits the growth of gram-positive bacteria.

LAB: Lactobacillus Vial

The Lactobacillus vial’s sensor detects production of CO2 . 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 Lactic Acid Bacteria metabolism in the liquid medium placed above the sensor, diffuses into the sensor and interacts with an indicator reagent to provide an indication of the presence of the carbon dioxide. The selective medium with a modified MRS is utilized.

Probiotic Vial

The Probiotic vial’s sensor detects production of CO2. 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 Probiotic Bacteria metabolism in the liquid medium placed above the sensor, diffuses into the sensor and interacts with an indicator reagent to provide an indication of the presence of the carbon dioxide. Selective medium with a modified MRS is utilized.

EC: E. coli Vial

The E. coli vial membrane vial (a membrane filter is used to separates the sample containing area where microorganisms may be present, from the reading zone where detections occur), monitoring the utilization of MUG (4-Methylumbelliferyl-3-D-Glucuronide) by E. coli (enzymatic reaction). The medium is highly selective for the detection of E. coli. MUG is the most commonly used fluorogenic substrate for the detection of E. coli. It detects the activity of glucuronidase by E. coli.

Combination Coliform/E. coli Vial

The combination vial is a membrane vial (a membrane filter is used to separates the sample containing area where microorganisms may be present, from the reading zone where detections occur), monitoring a change in color (Coliform) and fluorescence (E.coli). The production of the yellow ortho-Nitrophenyl-β-galactoside (ONPG) by coliform is monitored with a blue LED, while 4-methylumbelliferyl-β-D-glucuronide (MUG) utilization is detected by a fluorescence sensor.

SAL: Salmonella Vial

The Salmonella vial’s sensor detects production of CO2 . 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 Salmonella metabolism in the liquid medium placed above the sensor, diffuses into the sensor and interacts with an indicator reagent to provide an indication of the presence of the carbon dioxide. The selective medium inhibits all gram-positive organisms and many gram-negative organisms.

PSE: Pseudomonas Vial

The Pseudomonas vial’s sensor detects production of CO2 . 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 Pseudomonas metabolism in the liquid medium placed above the sensor, diffuses into the sensor and interacts with an indicator reagent to provide an indication of the presence of the carbon dioxide. The highly selective medium, inhibits gram-negative and gram-positive bacteria other than Pseudomonas spp, and relays on the utilization of Glycerol the main energy source.

STA: Staphylococcus Vial

The Staphylococcus vial is a membrane vial (a membrane filter is used to separates the sample containing area where microorganisms may be present, from the reading zone where detections occur); A selective medium containing Mannitol as the main carbon source monitoring changes in color due to pH shift as Staphylococcus utilize the sugar and produces acid.

Sanitation Monitoring

Enumeration of microbial populations on production surfaces and processing equipment surfaces are an important means of monitoring the effectiveness of plant sanitation. The procedure involves rubbing several areas of the surface to be sampled with a pre-wetted sterile swab. After swabbing the desired area the tip of the swab is cut and introduced into the TAC and/or YM vial(s).

Shelf-life

Estimation of shelf-life of fresh foods is based on estimation of number of the organisms responsible for producing spoilage of the product by producing objectionable odor, slime, etc. The product is slightly abused to encourage the growth of the spoilage flora followed by estimation of this flora numbers using the TAC vial. Products such as pasteurized milk, raw chicken, and raw seafood are examples of products that can use this procedure.

Spoilage Flora

This assay is very similar to the shelf-life assay; the flora responsible for spoilage is enriched following the estimation of this flora numbers using the TAC vial.

Sterility Testing

Products that are sterilized by Ultra-High-Temperature (UHT) can be screened to ensure that all viable cells and spores have been destroyed during the sterilization process. The assay is conducted to ensure that no microbial growth can be detected. In most cases, the food products are pre-incubated with or without growth medium to allow any possible growth in original container. The samples are then introduced to TAC and if required also to YM vials.

Preservative Efficacy Test

Challenge testing is mandatory for all products that in normal conditions of storage and use, run a risk of contamination by the consumer or a deterioration of the product exists. The challenge test consists of an artificial inoculation of the finished product and a posterior evaluation of the decrease of this contamination to acceptable levels over time. This ensures the microbial limits established for the product are meet. This assay is mainly performed in cosmetics and toiletry products. After the each time point the product containing the microorganisms is neutralized and entered into a MC vial.

MC: Microbial Content Vial

The Microbial content 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 placed above the sensor, diffuses into the sensor and interacts with an indicator reagent to provide an indication of the presence of the carbon dioxide. The vial utilizes a nutritious non selective medium and contains Tween and lecithin.

Thermophiles

A thermophile is an organism that thrives at relatively high temperatures, between 45 and 80 °C. The assay for thermphiles uses the TAC vials and a higher temperature of incubation.

Psychrotrophic Count

Psychrotrophic bacteria are bacteria that are capable of surviving or even thriving in a cold environment. They are of particular concern in the dairy industry. The assay for Psychrotrophs uses the TAC vial and a low temperature of incubation.

Available Assays:

Learn More:

• Vial Description: details of BioLumix vial technology and list of all available vials
• Vials: overview of the function of Membrane and CO2 Vials