On the sachets of the SACCO cultures, the name of the culture is displayed, example: SACCO LYOFAST MW TA 035 TA - 10 U

The 10 U indicates that the sachet is enough to inoculate 1 000 L of milk.

The sachets will however differ in weight from batch to batch, it all depends on the nutrients that the batches is grown in - so even if a sachet's weight decrease, or increase the amount of colony-forming units per sachet i.e. the "strength" will always be the same. 

10 U will always contain enough bacteria to inoculate 1 000 L of milk, irrespective of the weight of the sachet's content.