So far 24 employees and three family members who live in Lincolnshire tested positive for coronavirus from the outbreak at the Bakkavor Deserts factory..
The sudden increase in cases means Lincoln has been on the “red list” for a week — the longest an authority in Lincolnshire has been.
South Kesteven also appeared in the danger zone for a few days for the same reason but has since dropped off.
Council bosses are adamant, however, that there are no other major concerns in the county apart from the factory outbreak.
Tony McGinty, assistant director of public health at Lincolnshire County Council, said: “We’ve looked very long and hard at all of the positive cases that popped up in Lincolnshire and Lincoln particularly because it’s on our watch list now.
“I can’t see any additional random cases or any other outbreak situations other than that one.
“It’s given us nearly 30 additional cases, most of which have been in city of Lincoln area, in a relatively short period of time and because our numbers are generally quite low, that number of additional cases over a couple of weeks is going to push us onto the red list for a while.”
He said anyone connected with the new cases should have been contacted by the NHS Test and Trace service by now.
The factory has carried out more than 800 tests so far and found 76 cases. It has more than 1,600 employees.
Lincolnshire has so far had 2,626 cumulative confirmed cases and the official government dashboard shows 23 new cases this week.
Mr McGinty said the trend at the moment was around three or four a day based on the historic data.