Australian scientists have developed intelligent packaging that develops a clear "bruise" if it has been tampered with.
The flexible packaging changes colour to alert retailers or consumers it has been punctured or tampered with.
Food Science Australia's principal research scientist in packaging technology, Dr Robert Steele, said the idea for the bruise system came from apples.
"We developed a system to mimic the sort of bruising you get from an apple. If you puncture an apple it forms a brown stain," he said.
The new packaging is a natural red to light-pink colour. When punctured, the light and air react with the packaging in a process called photochemical oxidation to form a bruise.
Tamper-evident packaging had previously been confined to mechanical traps on rigid packages such as milk bottles, and shrink-wrap around boxes.
The new system would allow flexible packaging, such as biscuit packets, to be protected.
"Flexible packaging is the easiest one to interfere with and presents the least barrier to potential tamperers," Dr Steele said.