TORONTO -- Twenty-nine poultry farms in Ontario are now under quarantine after H5 avian influenza was confirmed on a turkey farm.

The Canadian Food Inspection Agency said last week that the disease was confirmed on a farm in Woodstock, Ont., and placed it and eight other farms under a quarantine.

The agency now says 20 additional farms are under quarantine.

The CFIA says all the farms are in an avian influenza "control zone" which has been established to control the movement of animal products and equipment in order to minimize the spread of disease.

The zone consists of a 10 kilometre radius around the farm in Oxford County where avian influenza is confirmed.

Dr. Abed Harchaoui, a senior staff veterinarian at the CFIA, says the additional farms have been placed under quarantine as a precaution.

He says there is no increased risk, nor is there any food safety concern.

"This move is an effective balance between strong disease control methods and the ability to resume trade," he said. "The agency is monitoring these additional premises closely for any sign of disease."

Harchaoui said the avian influenza control zone will be in place until the CFIA is confident the disease is no longer circulating in the area.

Avian influenza does not pose a risk to food safety when poultry and poultry products are properly handled and cooked.

The disease rarely affects humans that do not have consistent contact with infected birds.