Why is PBS prone to bacterial growth?

The ease of bacterial growth in a solution unrelated to phosphorus and sodium can be influenced by various factors:

1.     The solution, such as PBS (or other solutions), may not undergo sterilizing filtration. If the solution is contaminated with a significant amount of bacteria during the preparation process, their reproduction will be relatively faster.

2.     The solution, like PBS (or other solutions), may contain other substances such as proteins that promote bacterial growth. In such cases, the solution is more likely to become contaminated.

3.     Insufficient or lack of use of preservatives can contribute to bacterial growth. For example, in PBS solutions used for IVD reagents, it is common to add an antimicrobial agent like NeoCide PC-300 at a recommended concentration of 0.05-0.1%. If a lower concentration, such as 0.01%, is used, the risk of bacterial growth increases. Additionally, if the solution contains components that promote bacterial growth, even using 0.05-0.1% NeoCide PC-300 may not be effective. In such cases, a combination of two antimicrobial agents like NeoCide PC-300 and NeoCide BND-10 can be used to complement and synergistically enhance the antimicrobial effect, providing a solution to the problem. It is generally not recommended to increase the concentration of a single antimicrobial agent alone to solve the issue.