A security bag includes a tamper-evident closure which provides a visual indication if the closure is opened. The closure includes an ink layer deposited on one wall of the security bag or on a flexible strip secured to one wall of the security bag, and an adhesive layer in overlying relationship with...http://www.google.es/patents/US7223015?utm_source=gb-gplus-sharePatente US7223015 - Tamper-evident closure
