Reynolds Food Packaging of Sedgefield believes it has solved the perennial problem of how to create cost-effective, tamper-evident, light weight packaging via thermoforming.

From a Marks and Spencer brief Reynolds created new APET packs, now being introduced in M&S stores UK-wide for the Food to Go and snack, layered and wet salad ranges. The packs are said to be be easily lidded manually or mechanically, but with severe undercuts on the lid clips, the lids cannot be easily removed by tamperers.

The top face is encircled by a semi-perforated cut and has an upstanding pull-tab. Pulling this removes the lid in a similar way to a drinks can ring-pull, but here the lid can be reused to keep contents fresh.

Reynolds says the undercut/kiss-cut combination makes it impossible to remove the lids without fracturing the kiss-cut, making any tampering immediately evident. The TEP containers are patent pending.

Paul Scott, Reynolds sales director, adds: “It took over a year and cost £200 000 to arrive at packs which would be very difficult for an overly curious shopper to open, but which even someone with reduced dexterity would have no difficulty accessing at home.

Marks & Spencer has an exclusive 12-month agreement to use the technology.