The mistake left Ethan Smith questioning Four Square Port Chalmers’ practices and whether it was symptomatic of wider problems.
However, Foodstuffs said it was a "one-off incident" in which a cake that was meant to be thrown out was mistakenly put on the shelf.
Mr Smith noticed something was off with the label on the mud cake after leaving the store on Saturday afternoon.
After peeling back the Four Square price sticker, he uncovered a second tag for a mud cake from Pak’nSave Dunedin, in Hillside Rd.
The Pak’nSave tag listed a best-before date of the previous day, Friday, whereas the Four Square tag said it was still fresh for another week.
The price had also been marked up by $2.
"It was disgusting and I went straight back", Mr Smith said.
When he asked for a full refund, he said a staff member at the store told him the mud cake was only off by one day.
He received the refund but Mr Smith said his experience at the store led him to share the situation on social media.
"It made me realise that one day out was not bad for them."
Mr Smith believed the situation was "100% misleading" as opposed to a mistake and was worried the store could be selling other products, such as fresh meat, after their expiration dates.
A Foodstuffs spokeswoman said the mud cake’s wrong expiration date appeared to be "a genuine case of human error and a one-off incident".
Some of its in-store bakeries supplied baked goods to other Foodstuffs stores which were delivered unlabelled.
A staff member discovered one cake had a Pak’nSave label and the item was set aside at the back of the store with the intention it would not be sold.
However, another team member mistakenly labelled the cake with an automatically generated expiration date and placed it on a shelf.
"It’s disappointing when these things happen, and when things go wrong, we work to put them right.
"We’ve spoken to the team members involved and looked at how we can do things better to ensure that this won't happen again."
