Of those, 41 cases have been resolved, according Dr. Hsui-Li Wang, the acting medical officer of health for Waterloo region.
The plant closed for one week at the end of April to clean and sanitize the place and to install dividers.
At the time there were seven positive cases, but that increased to 44 during and shortly after the shut-down.
Even though the number of cases has increased, the rate of spread has continued to decrease, said Dr. Wang.
Her public health unit is working with the plant's management and with the ministry of labour.
"We are monitoring closely in partnership with the ministry of labour to determine the effectiveness of the enhanced PPE (personal protective equipment) and safety procedures that were put in place prior to their reopening on May 4," said Wang.
