The system, which has been designed by Torex Retail, enables store staff to electronically log ID requests, the form of ID used and purchase refusals.
The information can be used by the Spar retailer's head office in Dundee to highlight problem stores.
The company can then target these outlets for better staff training.
"If we have got a problem in Aberdeen or Glasgow, we can target our training at these areas," said Graham Murdoch, IT director. Many retailers tended to use handwritten logs for age-restricted purchases, he said, but they often found them inconvenient and so ended up not bothering to fill them in.
Trials in four stores proved the touchscreen system was easier to use and was flagged up by a bigger on-screen message, forcing retailers to think through their actions, said Murdoch.
"Previously, when age-restricted products were scanned, the till operator got a yes/no message on screen asking if the customer was older than 18.
"That became routine. But this system is really in your face."