The Canadian Food Inspection Agency has ordered a recall of more than 250 ground beef products from an Alberta plant because they may be contaminated with E. coli bacteria.

This timeline outlines events related to that recall:

Sept. 3: Random testing at the U.S. border finds E. coli in a shipment from Alberta's XL Foods. That shipment is placed on "hold," as is standard policy, and triggers testing of the next 15 shipments from the company. Of those, two test positive.

Sept. 4: U.S. officials inform CFIA, which has also discovered E. coli through routine testing.

Sept. 12: CFIA is informed of two more positive E. coli tests in meat crossing the U.S. border.

Sept. 13: CFIA investigation team goes to the XL Foods plant in Brooks, Alta.

Sept. 16: CFIA issues first recall. In the following nine days, the recall is expanded six times as more information becomes available.

Sept. 25: U.S. bans import of beef from XL Foods.