A cyberattack on one of the country’s biggest milk brands has forced the dairy to suspend operations while it sorts through the chaos.

Coca-Cola, which owns Fairlife, disclosed on Thursday that the dairy’s systems “identified unauthorized access by a third party” to some of its internal systems, including systems that control production. The company described the hack as a ransomware event, indicating the hackers sought to lock up parts of its operations to demand a payment.

Fairlife’s milk products are one of the fastest-growing brands in dairy, driven by consumer interest in high-protein drinks. The brand’s line of milk and chocolate milk advertise an “ultra-filtration” process that uses special filters to concentrate protein and calcium content while filtering most sugar out.