US meat processor Tyson Foods has said its four Mississippi poultry processing plants were idled early last week by hurricane Katrina, primarily because of the loss of power.

The company, which donated food to the relief effort, said all four are now back in operation and are currently running near pre-hurricane production levels. Carthage resumed production last Wednesday, the two Forest plants on Friday and Vicksburg on Saturday.

"While it remains difficult to precisely calculate the financial impact of Hurricane Katrina on the company, Tyson today provided a cost estimate in the $10-20m range.  This reflects the loss of some live bird inventory, the temporary closure of processing plants and the loss of frozen product that was in storage at ports in Mississippi and Louisiana," the company said.

Because of these projected fourth quarter expenses, the company has lowered its 2005 earnings guidance by 3 cents per share to $0.92 to $1.02 per share.