Technical note – effects of seaming conditions on external and internal double‐seam characteristics in round metal cans

Canning is the major packaging technology for fully preserved food products. To obtain safe canned foods with extended shelf-life, the closed cans have to be hermetic. The consistency and quality of the seaming process are crucial to food safety. This note investigates the effects of different seaming conditions (base-plate pressure and seaming-roller pressure) on external (seam thickness, seam height) and internal (body hook length, overlap, lid hook length, seam gap and body hook butting) double-seam characteristics in round metal cans. External double-seam characteristics were significantly affected by the seaming-roller pressure during the final closure of the cans. Generally, there were small effects of base-plate pressure on the external double-seam characteristics. In contrast, all the investigated double-seam characteristics were affected significantly by the seaming-roller pressure, whereas only body hook length and seam gap were significantly affected by the base-plate pressure. This note illustrates the importance of close control and optimization of the seaming conditions during production of canned foods as a means to reduce the processing induced variability in double-seam characteristics, and subsequently to obtain safe and high-quality canned products. Copyright © 2005 John Wiley & Sons, Ltd.