#ERIAL DILLUTION VS PARALLEL DILUTION SERIAL#

For a demonstration, see our demo videos. At the touch of a button, 9 mL of diluent flush the sample out of the pipette tip into the bag, creating an intense vortex together with a sterile air blast, this process ensures a perfectly homogeneous mixture in less than 4 seconds.

The sample together with the pipette tip is put into the first bag, and the dispensing nozzle is connected to the tip. This makes viable cell count determinations much more efficient and reliable, and the dependence of the findings on the individual way of working is considerably reduced, as the following independent experiments show. Pipetting becomes more convenient and precise as the sample is automatically rinsed out of the pipette tip to fully participate in the dilution process.

#ERIAL DILLUTION VS PARALLEL DILUTION SERIAL#

In contrast to manual dilution in test tubes, the Serial Diluter automates and standardizes the mixing and dilution of samples in accordance with ISO 6887-1 in a functional and resource-optimized polyethylene bag (Figure 1). Careful operation, as well as work experience, is the prerequisite for homogeneous dilutions leading to reliable and repeatable viable cell count determinations. Lab technicians experienced in undertaking serial dilutions know very well that in addition to the mixing time, the speed of the vortex movement, as well as the angle of how the test tubes are applied on the vortex mixer, influence the degree of homogenization. For example, it is recommended to mix samples in test tubes with 9 mL of diluent for about 5–10 seconds using a vortex mixer. The international standard ISO 6887-1: 2017 defines the technical requirements for this fundamental microbiological technique as well as including some recommendations. A representative sample and the correct serial dilution are the key factors in obtaining accurate results.

After the given incubation period, the colony-forming units (CFU) are counted, and the concentration of viable organisms in the original sample can be calculated from the dilution factor. For this purpose, 1 mL of the homogenized sample to be tested is diluted in 9 mL of sterile diluent over several dilution steps, resulting in a dilution factor of 10, followed by inoculation of agar plates with the diluted samples. Serial 10-fold dilutions of homogenized samples for viable cell count determinations are part of the standard tests of most microbiological control laboratory testing food, beverages, animal feed, and cosmetics. Thus, the quality of the testing results obtained is increased, and the use of test tubes eliminated. The automatic dilution process is completely independent of the different working styles and experience of the operator. Laboratory trials and proficiency testing have shown that the automated sample dilution provided by the Inlabtec Serial Diluter increases reliability and accuracy of food testing compared to the traditional manual test tube method.

Erial dillution vs parallel dilution