Major German seafood processors Frosta and Deutsche See have been hit with an outbreak of COVID-19 at their respective operations in Bremerhaven, Germany.

As of Tuesday evening, 26 employees tested positive for the virus at Deutsche See, reports Weser Kurier.

On Monday, Frosta reported 29 employees had tested positive for the virus.

No additional employees tested positive since then, a representative with Frosta confirmed for IntraFish on Feb. 5.

Over the weekend, production at Frosta's Bremerhaven plant came to a standstill as a result. Operations are already running normally again, the Frosta representative said.

Before each shift starts, employees at both Frosta and Deutsche See are now swabbed with a quick test.

“We are in close contact with both companies, environmental investigations were initiated at an early stage and will continue to take place,” said Ronny Mockel, head of the crisis team and the health department in Bremerhaven. "Further cases are to be expected in the coming days."

How exactly the virus spread in the two factories is currently unclear.

The cases are particularly worrisome given that Bremerhaven is the center of frozen fish product processing both for German distribution and for Europe in general.

In addition to Frosta and Deutsche See, Nomad Foods operates a major frozen fish processing plant in the town. Both Frosta and Nomad are significant buyers of frozen Alaska pollock and Atlantic cod, as well as other whitefish species and salmon.

A rash of recent COVID-19 cases in Southeast Alaska has impacted major Alaska pollock processing plants, raising supply concerns, though in recent days companies have reported progress on containing the outbreaks.