Staff who serve food at an Auckland private girls school are undergoing training after serving sushi to students a day after its use-by date.

A group of about 50 boarders at St Cuthbert’s College were served the packaged sushi, with an expiry date of Friday, for lunch on Saturday.

The error was discovered before any of the students ate the expired food, but a parent of one girl expressed concerns the students could have fallen ill right before their exams if they had eaten it.

College Principal Lynda Reid said the incident had been discussed with catering company Alliance.

When the error was spotted a different lunch was served.

“Alliance serves millions of meals each year across New Zealand and Australia and food safety is its highest priority,” the company said.