A fresh Jalapeno Pepper will last from 1 to 2 weeks and sometimes a bit longer before it starts to go bad and if you refrigerate the fresh Jalapeno it could last up to a month and possibly longer.
Canned Jalapenos can last up to a few months in the refrigerator as long as you keep them refrigerated.
If the canned or Jar Jalapeno Peppers have not been opened they can last up to a year or more on the shelf even after expiration date.
When a Jalapeno Pepper starts to go bad it will usually start wrinkling up or the pepper will have a different or bad smell to it and the color will start to change.