These days there are many diagnostic techniques available to bottlers and watercooler companies who want to take the do-it-yourself approach. These techniques can shorten the time to obtain a result such as TVC and save you money.
Which technique you choose depends on the degree of accuracy required. Dip slides have been around for a long time. These are a low-cost and convenient option for assessing bacterial contamination. A slide is dipped into the water sample, returned to the transparent container and incubated for 24-48 hours at 37 degrees C. After this time, the colony count is compared with a series of photos which indicate the degree of contamination.
New developments in dip slides enable you to determine different bacteria types on each side of the dip slide, for example, TVC on one side and Ps. aeruginosa on the other. The dip slides also are hinged at the top, which allows surface sampling.
An alternative system called Petrifilm (TM) enables you to obtain an accurate count of CFU per cm2 from a measured volume of water. A 1ml sample of water is taken with a disposable pipette and added to the centre of the film. The film is then covered and stored in an incubator at 37 degrees C for 48 hours. Counting CFUs is made easy by a red indicator dye which colours the CFUs and a built-in grid which enables the CFUs per cm2 to be determined easily.
If you want an immediate indication of contamination, then you require an ATP meter. Dip a swab in the water or swab a surface to be assessed and place the swab in the meter. An immediate numerical reading results. Now, this is not the actual TVC, but an indication that contamination is present. The higher the reading, the greater the contamination.
Petrifilm bringing the modern,reliable convenience of food microbiology testing to the global water and beverage processing industries..This innovative method provides alternative testing process to traditional agar petri dishes..large ton of information here for me to learn..Thanks for sharingReplyDelete