The Flow VIT® test kits enable the rapid quantification of live bacterial cells directly from the sample, without the delays and selection biases of classical cultivation methods. By using fluorescence in situ hybridization (FISH) in combination with flow cytometry, microorganisms can be identified and quantified within a few hours, whereas conventional cultivation methods often require several days.

A decisive advantage of Flow VIT® is the detection of viable but non-culturable (VBNC) cells, i.e. bacteria that are metabolically active but cannot be cultivated. These organisms remain undetected in conventional plate count tests, although they play an essential role in the efficacy of probiotic products and in the human gut. Since Flow VIT® uses rRNA as a target site for its VIT® gene probes - a marker for active protein synthesis - VBNC cells are also reliably quantified. This leads to a realistic assessment of the actual probiotic viability and prevents the systematic underestimation that occurs with cultivation-dependent methods.

Through this cultivation-independent methodology, Flow VIT® provides an accurate, fast and comprehensive analysis of the viability of probiotic microorganisms - a decisive advantage in product development, stability testing and quality control.

The Flow VIT® technology can be automated and provides clear, objective and reproducible results. The combined use of VIT® gene probes and highly sensitive flow cytometry enables standardized and objective quantification. The software-supported analysis allows the automatic evaluation of large sample series. This makes Flow VIT® ideal for quality control in industrial production.

In contrast to the classic colony forming unit (CFU) determination, which is dependent on the cultivability of the bacteria, Flow VIT® detects the actual number of living cells directly in the sample. The quantitative results are expressed in live cells per milliliter (cells/mL), which allows an accurate assessment of viability and stability.

Flow VIT® only detects living cells. This ensures that only metabolically active and intact microorganisms are detected and quantified. Dead cells are not detected. This enables precise differentiation between living and dead cells.

In contrast, PCR and other molecular biological methods are based on the detection of DNA, which remains detectable for a long time even from dead or lysed cells. This leads to an imprecise determination of the microbial cell count, as DNA-based methods cannot distinguish between living, dead or fragmented cell residues. Especially in the case of probiotic products or stability-critical fermentation processes, this can lead to an incorrect assessment of the actual viability and product quality.

Through FISH-based, cell-selective quantification, Flow VIT® thus offers a superior alternative to DNA-based methods by exclusively detecting live probiotic microorganisms and thus enabling a realistic count of live microbial cells.

The Flow VIT® test kits use highly selective, specially developed VIT® gene probes that enable the precise identification of individual bacteria or entire groups within a sample. This ensures that only the desired probiotic bacteria are quantified.

The combination of FISH and flow cytometry allows detection even in complex industrial sample matrices such as capsules, powders or fermented products. Thanks to VIT® optimization, even low cell counts in heterogeneous formulations can be reliably determined.

The high sensitivity of the method also enables precise monitoring of probiotic populations throughout the manufacturing process, including fermentation, stability testing and final product control.

Flow VIT® has been specially developed for industrial use in probiotic quality control, product development and research. The advantages include:

• Batch release with high reproducibility: results in a few hours, instead of waiting days for cultivation results
   
• Reliable stability testing: Precise viability analysis throughout the shelf life
   
• Optimization of fermentation processes: Insights into microbial dynamics
   
• Compliance with regulatory requirements: Specific quantification and identification for accurate declarations