Middlesbrough Council is supporting a major food business in the town after a number of positive Covid-19 tests among its workforce.
The Council arranged for a mobile testing unit to visit SK Chilled Foods' premises on the Riverside Park Industrial Estate on Friday and Saturday.
Testing was deployed to provide reassurance and help public health officials understand more about the spread of infection.
A total of 35 positive cases were recorded over the weekend, bringing the total at SK Chilled Foods to 50 since September 24. The company employs 400 staff at its Riverside facility and 900 staff in total across the whole of its business.
SK Chilled Foods is working closely with public health and public protection staff from the Council and has been praised for its cooperation.
Environmental health officers have inspected the premises and advised the company on measures designed to mitigate against the spread of infection.
Esther Mireku, Consultant in Public Health at Middlesbrough Council, said: "It is standard procedure for us to arrange wider testing after clusters of this sort linked to any setting.
"We have high levels of transmission of Covid-19 in the Middlesbrough area at present and the testing at SK Chilled Foods will help us understand more about the spread of the virus
"The Council, with support from Public Health England, is assisting the company as we attempt to reduce the spread of infection.
"SK Chilled Foods has good practices in place, and we will continue to work closely with the company."
A spokesperson for SK Chilled Foods said: "The health and wellbeing of our staff is our number one priority and once the scale of Covid-19 was known in March we immediately took steps to protect our staff.
"Given the environment they work in, they already wore full PPE and rigorous cleaning procedures were in place, but in addition we introduced new measures such as staggered shifts which gave staff more space and therefore encourage social distancing, and perspex screens have been installed in the staff canteen. Face visors were also added to the PPE at an early stage
"Staff who have tested positive are now self-isolating in line with government guidelines and we will continue to liaise closely with the Council's environmental health officers whilst operating to the very highest standards."
Anyone with Covid-19 symptoms should self-isolate along with those they live with. The person with symptoms should book a test immediately. The symptoms of Covid-19 are a high temperature, a new continuous cough or a loss or change to the sense of taste or smell.
Hundreds of tests are available daily in Middlesbrough at sites at Cannon Park and Teesside University.
Free tests can be booked online or by calling 119.