I have done a great deal of research on the topic of healthy dark chocolate, in general, and Xocai, in particular, as part of my decision making process to join up with Xocai. In addition to selling their products, I first became a user following my mother and my wife after personally witnessing the health benefits they realized.
As for expiration dates, if you look on the bottom of the boxes, you will see a "Best Used By" date. If you have a particular product that does not have a Best Used By date, you should contact Xocai through their website for an explanation. You will find it is a company that is very committed to the science behind healthy chocolate as well as the legal procedures. They will be happy to respond. Just as an FYI to further support Xocai's reputation - their distributors are routinely advised that any promotional material and/or statements about their products must be company-approved in order to protect against false or mis-leading claims. Xocai products also carry the Brunswick Lab seal of approval. Here are a couple of sites/articles where you can find quite a bit of information about dark chocolate (and, yes, it does matter if it is dutched as higher temperatures used in the dutching process have a destructive effect on the antioxidant elements) and Xocai products in particular: 1.
http://www.baileyshealthstore.com/store-categories-Healthy-Chocolate_3614686.html then click on any product for detailed information. 2.
http://www.mxi.myvoffice.com/clarkbailey or
http://www.mxicorp.com for more information about Xocai. 3.
http://www.baileyshealthstore.com/nutritional_benefits_of_chocolate/ for more information about what makes healthy dark chocolate healthy.
I sincerely hope this information is helpful to all of the people who have questions about dark chocolate and/or Xocai.