Expiration Date of a Mix
It is important to closely monitor the expiration dates of extracts so that no product is used beyond the assigned date. The manufacturer’s expiration date is the ultimate end date for all materials made from a manufacturer’s concentrate.
When mixing extracts, the expiration date of the mix is the same as the earliest expiration date of the components. In other words, the expiration date of the individual extract with the shortest shelf life will be the expiration date of the mix. If one component of the mix has expired, the quality of the mix can no longer be guaranteed.
This is especially important when using Ragweed extracts since these have shown lower stability than other pollen extracts. This demonstrates the importance of considering stability when planning a mix.
In the above example, Short Ragweed has the earliest expiration so this will become the expiration of the mixed vial: 11/2012.