A cyberattack disrupted refrigeration systems in 700 French supermarkets overnight between Oct. 11 and 12, causing temperatures in some units to spike as high as 80°C and forcing stores to discard spoiled food, French Finance Minister Roland Lescure told Parliament on Tuesday. The attack targeted connected cooling systems supplied by Danish manufacturer Danfoss, with most affected units being older models no longer receiving security updates, the company confirmed .

The Paris prosecutor’s office opened an investigation into the incident, which Lescure called a “wake-up call” for food security, though he stated there was no risk to national supplies. Dominique Schelcher, CEO of grocery chain Coopérative U, said 80 of its 2,000 stores were affected, with some forced to throw out food. Hackers remotely extended defrost cycles from one hour to eight, delaying alarms and worsening damage, according to store owners .

Danfoss stated it had long advised customers to update systems and use firewalls, and was assisting affected retailers. French cybersecurity agency ANSSI reported that Copeland and Dixell refrigeration systems were also compromised . The attack’s scale—hitting chains including Intermarché, Carrefour, and Monoprix—prompted Danish supermarket groups to review their own cybersecurity measures, though none reported disruptions . No group has claimed responsibility.