The TSA or the tryptic soy agar is formed of casein and soybean meal, this formation helps in the appropriate growth of a huge array of non-fastidious and fastidious microbes. This combination of soy and casein provides organic nitrogen in the form of polypeptides and amino acids, which makes the medium more suitable for growth.
In the given case, if one permits the incubation of the dilution tubes for 24 hours prior to plating them on the TSA agar plates than there is a more probability of the result to get affected. As if unlimited resources are already present in the tubes, it will provide more favorable conditions for the formation of more colonies and thus will influence or change the colony-forming units per milliliter.
Even if the dilution is performed in a hood and in an autoclaved medium then also there will be an increase in the colonies of the microbes as in the time of 24 hours interval more microbes will get differentiated and will increase in number.
