FP - Seal Defects (Blister)


  • A major defect if the width of the continuous intact seal is reduced to less than 3 mm (3/32-inch).
  • A minor defect if there is 3 mm (3/32-inch) or more of continuous intact seal.


A blister appears as a void within the bonded seal. A blister resembles a bubble or has a raised appearance in the sealed area of the retort pouch.


Food, grease or other contaminants were present in the seal area during seal formation.