LONDON — The owner of a take-away restaurant and a deliveryman in Britain have been found guilty of manslaughter for delivering food to a teenage girl who died from the effects of a peanut allergy.

The teenager, Megan Lee, who was 15 at a time, suffered a reaction after ordering from her local takeout in Lancashire, in northern England, in late 2016, according to local news reports.

She suffered irreversible brain damage after the allergy attack and died on Jan. 1, 2017.

On Friday, a jury at Manchester Crown Court found two men, Mohammed Abdul Kuddus, 40, and Harun Rashid, 38, guilty of manslaughter by gross negligence in Ms. Lee’s death. Court reports said that Mr. Kuddus had been the owner of the restaurant, and Mr. Rashid the deliveryman.

According to the prosecution, the restaurant, the Royal Spice Takeaway in Oswaldtwistle, Lancashire, had no systems or conditions in place to protect customers with allergies.