A Sainsbury's in Portsmouth has been banned from serving alcohol for 48 hours after selling to under-18s.
The supermarket on Fitzherbert Road, Farlington will be banned from selling alcohol from 8-10 May. The store will remain open for other sales.
Staff at the outlet served under-18 test purchasers three times in a three-month period.
"There were options available to us and on this occasion we offered Sainsbury's two options," said Sergeant Wendie Douglas.
"Under Section 169A(2) of the Licensing Act 2003 Sainsbury's could either accept the 48 hour alcohol closure or decide to go to court. Sainsbury's chose to accept the 48 hour ban."
She added: "Stores do not want to sell alcohol to young people and alongside Trading Standards we are offering support and training, giving stores the chance to retrain their staff using the recently launched training package from Trading Standards.
"Officers have carried out a number of test purchase operations at Sainsbury's since March and on each occasion staff have refused to sell alcohol to the young people which shows they are taking their responsibilities seriously.
"Sainsbury's have taken the failures very seriously and will continue to work with us in training their staff and refusing to sell alcohol to young people."
A Sainsbury's spokesman said: "We would like to apologise to any customers who have been inconvenienced by this temporary suspension.
"Sainsbury's is a responsible retailer so we have implemented a Think 25 policy and we will be working closely with the local authorities to help prevent this happening again."