New England Biolabs now has a policy of assigning expiration dates to many of our enzymes and reagents. This policy is designed to satisfy the needs of a growing number of our customers who require such information to meet their regulatory requirements. For such customers, the expiration date indicates the period of time over which NEB will guarantee 100% activity of the enzyme if stored under the recommended storage conditions.*
Our expiration dates have been developed as a result of many years of experience with our products and represent a minimum guaranteed life expectancy for full activity of a given product. It is not the intent of this dating policy to imply that a product will necessarily lose activity after the expiration date. In fact, many of our enzymes will retain significant, if not full, activity for many months or even years after the expiration date. For many basic research applications, enzyme vials may be suitable for use well past their stated expiration date. Disposal and or continued use of enzymes past their expiration dates should be at the discretion of the end user.
* Enzymes should be stored long-term at the recommended temperature (most often -20°C; some enzymes have alternate recommended storage temperatures, such as -80°C). During use, enzymes should be stored on ice, and then returned to their long term storage conditions promptly after use.