Dole Plc announced in a memo obtained by CNN that their system suffered a ransomware cyberattack earlier this month, causing lettuce shortages in some supermarkets.

The first signs of the effects of the attack were reportedly empty salad bars and shelves due to a shortage of Dole's pre-packaged salads.

Customer complaints led the company to send the memo on Feb. 10, informing grocers of the cyberattack.

This form of cyberattack, ransomware, is malicious software that prevents users from accessing their computer files, systems, or networks, until they pay a ransom to regain control. According to the FBI, it can encrypt files and folders on local drives, attached drives, and networked computers.

Regarding the issue, William Goldfield, Dole spokesperson, told CNN that: “The company has notified law enforcement about the incident and is cooperating with their investigation.

“While continuing to investigate the scope of the incident, the impact on Dole operations has been limited.”

Employees and store owners across the country have struggled to get Dole salads on their shelves for several days.

"Our plants are shut down for the day and all our shipments are on hold," the internal memo read. "Please bear with us as we navigate our way and hopefully we will minimize this event," said the memo sent out by Dole.

Dole plc operates four processing plants and currently employs more than 3000 people, according to a press release from the company.

Ransomware is one type of cyberattack suffered by members of the food industry which has led authorities to crack down on cybercrime groups that generate hundreds of millions in revenue every year from their activities.