Sapra Retails Limited, trading as Loco Store, in Unit 1, Longfield House, Longfield Road, Twyford was fined £195 and ordered to pay £1,334.60 and a £30 victim surcharge by Reading Magistrates after pleading guilty to the sale of alcohol to a person under the age of eighteen on 18 February.
The prosecution followed a test purchasing exercise involving a 15-year-old volunteer organised by West Berkshire and Wokingham Trading Standards Service.
The teenager entered the store and attempted to buy and was subsequently sold a four-can pack of Guinness without age verification from the seller. The subsequent investigation found that the company, had failed to take adequate steps to prevent that sale taking place.
In passing sentence the magistrates acknowledged the timely guilty plea entered on behalf of the company.
Cllr Pauline Jorgensen, executive member for resident services, said: "It is imperative that retailers of potentially harmful products take adequate steps to ensure that alcohol is not sold to young people.
"This includes taking steps to ensure that staff are adequately trained and that there is a robust proof of age policy in place."
Any Wokingham or West Berkshire resident or business who has concerns about illegal sales of age restricted products is asked to contact the Trading Standards helpline on (01635) 519 930 or email: firstname.lastname@example.org.