Walkers has confirmed 28 staff at its factory in Leicester have tested positive for coronavirus.
The crisp giant, which employs 1,400 at its Beaumont Leys site, said it had seen a “steady increase” in confirmed cases in June.
A local lockdown has been announced in Leicester after the number of infections in the city rose.
Walkers said its products were unaffected, and transmission of the virus was “not in our factory”.
“The advice from DEFRA and the Food Standards Agency is clear – it is very unlikely that people can catch Covid-19 from food,” added a spokeswoman.
“We do not anticipate any disruption to the supply of our products.”
The firm said the increase in confirmed cases reflected the situation in the local community.
It was “in regular contact” with health authorities and the government, the spokeswoman said, and was “reassured” it had the correct measures in place to protect employees.
She said employees with a confirmed or suspected case of Covid-19 were self-isolating on full pay and Walkers continued to “maintain the highest level of vigilance”.