Grocery stores across Europe have been hit by another wave of suspected cyberattacks, reporting sudden changes in the temperatures of their fridges and freezers. Major supermarket chains across Belgium, Sweden, Luxembourg, and Estonia were affected according to local reports shared by Bloomberg and Reuters.

One Ica Kvantum store in Sweden said on its Facebook page that its fridges and freezers had been hacked overnight, with temperatures remotely raised to 50 degrees Celsius (122 Fahrenheit). In a statement to Business Insider, a spokesperson at Swedish supermarket chain Coop also confirmed that “unauthorized actors were able to access and tamper with the cooling systems at a small fraction of our stores.” Dutch retailer Ahold Delhaize said an “IT incident” was responsible for adjusting the temperature of refrigeration units in dozens of its ⁠supermarkets in ​Belgium ‌and ‌Luxembourg. The full scale of the incident has yet to be confirmed.

Many modern supermarket fridges and freezers are connected to the internet to support remote maintenance and system failure alerts, but the increasing number of these suspected hacks is raising concerns around how security flaws can impact food supply chains. This latest incident follows an apparent cyberattack that targeted hundreds of French supermarket refrigerators last month, with the resulting food spoilage estimated to be worth millions of Euros, along with a string of US military base freezer malfunctions also suspected to be the result of a cyberattack.