Shop freezers in seven European countries hit by cyber-attack

Stephan Moelans, the CEO of Sabcobel, which operates Delhaize's systems, on Monday told the Belga news agency that the incident was a cyber-attack and that the company had been "working all night and morning to disconnect the affected units from the network".

He said since the French attack in early October, the company had been working to "protect our customers fridges against this vulnerability" but that the units needed physical modifications, not just software updates.

Most supermarkets across Europe are linked to the internet, and maintenance and troubleshooting can be done remotely.

"The simplest solution is to manage the fridges over a secure internet connection. Most of our customers switched to that after the attack in France," Moelans added.