The Office of Fair Trading is urging residents to check prices at the till after finding misleading pricing.
Trading Standards inspected 31 food retailers across the Island and issued advisory enforcement notices to more than half.
It said issues such as shelf prices not matching till receipts, expired offers still being promoted and misleading labelling were found.
Office of Fair Trading Chairman Tim Glover MHK described the findings as "disappointing" and said the public should report any issues directly.
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