Perhaps I missed it. I checked and read the site and did not see a guarantee as to the quality of freshness upon arrival, no mention of "when" the bottle being purchased is manufactured or how long it may have sat on a shelf before being shipped. I did read about the acid-proof delivery system which has to do with a coating that helps the probiotics to survive the acids of the stomach so that they make it to the intestine unharmed. Is this the delivery system you referred to?