Retailer Coles has been fined more than $31,000 for displaying food beyond its use-by date at its McLaren Vale supermarket on Adelaide's southern outskirts.

The Magistrates Court was told some of the 33 items including packaged salami and shaved ham were about two weeks out of date.

Magistrate David Whittle said the store's date-checking process had failed as many as three times.

Lawyers for Coles entered guilty pleas on seven counts of breaching the food code and the prosecution dropped another 15 charges.

Coles had recently moved to new supermarket premises in the Main Road shopping centre when council inspectors found the out-dated items last year.

The magistrate said the store staff had been under considerable pressure.

"The Coles supermarket at McLaren Vale had been recently opened to replace an older, smaller store. A larger than forecast increase in customers and business had occurred," he said.

"Working in the new store was a mixture of employees from the old supermarket [and] new employees of whom a number had not previously worked for Coles, and other Coles employees who had been transferred from other stores."

The magistrate said there was no evidence the items had become unsafe but out-of-date food had the potential to be a risk to public health.

Mr Whittle said the fine should serve as a warning to other food retailers of the need for diligence.

"The defendant has expressed deep regret and sincere remorse for the offending. I have accepted that it takes a proactive approach to compliance with its obligations and took immediate steps to overcome identified deficiencies in its processes," he said.

"General deterrence is the primary consideration, that is the penalty must be such as to deter food retailers, large or small, from breaching their obligations relating to the sale of food, and particularly from allowing food to be displayed past its use-by date."

The court was told Coles had changed its procedures to avoid any repeat of the problem.

The company also issued a statement: "At Coles we take food safety seriously and our South Australian stores have had an outstanding record in this area," it said.

"We set high standards and when we do not meet them we take accountability and fix the problem."

The court also ordered the retailer to pay $10,000 for Onkaparinga Council's legal costs.