Italy's government held emergency talks with intelligence chiefs on Tuesday following cyberattacks on supermarket freezer systems in at least 11 European countries.
The attacks in recent days, for which no one has claimed responsibility, have prompted the EU to warn of a deliberate attempt to disrupt its food supply chain.
EU spokesman Thomas Regnier said EU agencies were also holding meetings on Tuesday with national authorities on "how to best respond to this collectively".
"The investigations are currently being carried out by the national authorities, and we are in close contact with them," he said.
"These are not isolated incidents, and of course, we have to be collectively resilient and prepared for such cyber incidents."
Supermarkets in Belgium, Estonia, Finland, Germany, Ireland, Italy, Luxembourg, the Netherlands, Portugal, Romania and Sweden reported refrigeration problems that forced several retailers to discard food after temperatures rose.
The incident came three weeks after a cyberattack disrupted French grocery stores and led hundreds of outlets to throw away spoiled stock.
The EU food and agriculture commissioner, Christophe Hansen, said on Monday the bloc was taking the incidents "very seriously".
"They are a deliberate attempt to disrupt our food supply chain and undermine consumers' confidence in it -- a warning that we must take seriously," Hansen said.
In Italy, government ministers had a meeting with intelligence chiefs and the National Cyber Security Agency, which also issued technical advice for retailers to protect their systems.
"Initial investigations show that, in Italy, the impact of the attacks is currently highly limited. Only a small number of commercial units have been affected," the government said in a statement.
It said affected outlets had "outdated security systems, with interfaces exposed directly to the internet and weaknesses in authentication mechanisms".
There were reports of around 20 outlets affected nationwide in Italy.
Giuseppe Spadaro, director of a group that manages the Coop supermarkets in Sicily, said four of the company's 300 stores were hit.
"We estimate the damage at several thousands of euros. We had to throw away everything. The shelves are empty. We are waiting for suppliers today to replenish the stock," he was quoted as saying by the Corriere della Sera daily.
"To be honest, we did not think that as supermarkets we would be targeted by a cyberattack. This shows that any connected device can become a target. So we will invest more -- that is essential," he said.
Four supermarket outlets were affected in Germany and six in Romania, officials and company representatives said on Tuesday.
"No other infrastructure was compromised," Dan Cimpean, director of Romania's National Cyber Security Directorate (DNSC), told AFP.
"It seems semi-amateurish. We do not suspect, under any circumstances, that it is a state actor," he said.
Carlos Cancinos, spokesperson for the Coop chain in Sweden, said that the group's seven affected shops had resumed "normal functioning".
Refrigeration equipment and freezers affected overnight from Monday to Tuesday were connected to "old 4G networks", he said.
"We have launched a major programme to modernise a large part of our store network, equipping connected refrigerators and ensuring that they operate via 5G networks. This helps to solve a large share of problems of this kind," he said.
Belgium was among the hardest-hit countries, with dozens of stores across several grocery chains reporting refrigeration failures. Federal prosecutors there have opened an investigation.
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