Investigations into the case continued and scoping suggested they only attended the supermarket once while infectious, on August 12.
"Apologies to Pak'nSave Glen Innes and Foodstuffs if that longer period that was indicated yesterday has caused any issues," Bloomfield said.
"The person is considered to be low risk and employees and other shoppers also, therefore, at low risk."
It comes as officials report six new cases of Covid-19 today, one of which is in managed isolation.
The other five cases are in the community, all linked to the South Auckland cluster.
Prime Minister Jacinda Ardern said today's results were "encouraging" and there appeared to be no surge in community cases.
Auckland Regional Public Health Service has advised Foodstuffs, the owner of Pak'nSave, about the mistake yesterday.
Staff and shoppers who were at the store at the time were considered to be at low risk, Foodstuffs said in a statement.
ARPHS has asked anyone who was at the store at the time to be vigilant for Covid-19 symptoms.
Anyone experiencing symptoms, including a sore throat, new or worsening cough, fever, or loss of smell, should call Healthline for advice.
The error about the shopper's movements comes after Bloomfield last week said Pakuranga College was closed and linked to a new case of Covid-19.
Pakuranga College principal Mike Williams was later told it does not have a positive case at the school despite the announcement.
He said the error caused "huge stress in our community" and left him with no confidence in the health system.
"If that's how their system is, it's no wonder we've got Covid," he said.
"It doesn't give you any confidence, does it? Can you have confidence in the Ministry of Health any more? No."
And on Monday, David Letele, known as the Brown Buttabean, says a positive Covid-19 case attended a fitness training class in west Auckland, not Kingsland as reported by Bloomfield.
Bloomfield announced the case had attended a Buttabean Motivation class on August 10, however, Letele said the case attended a class in west Auckland.