The 39-year-old, who cannot be named for legal reasons, appeared in the dock at Kidderminster Magistrates Court on Wednesday.
Adam Cech, 27, and Jan Dudi, 25, both from Birmingham, Norbert Pulko, 22, from London and Jabar Paktia, 41, of Wolverhampton, have also been charged over the incident.
The boy suffered serious burns to his face and arm at the Home Bargains store in Worcester on Saturday afternoon and was discharged from hospital the following day.
Magistrates were told by Stephen Davies, prosecuting, that the boy and his mother were now “in a place of safety”.
It is not yet known whether the youngster has suffered longer term implications as a result of his injuries.
The attack occurred in the Tallow Hill area of Worcester, while the boy was out with his mother and other children.
During a lengthy hearing, the men, all dressed in grey tracksuits and white T-shirts, spoke only to confirm their names, ages and addresses.
All, including Slovakian nationals Mr Pulko, a registered carer for his disabled mother; Mr Cech, a father-of-two who is a team leader at an Oliver James Foods factory; and father-of-two Mr Dudi; denied any wrongdoing through their solicitors.
Angela Channon, chairman of the bench, remanding the men into custody, told them they will will next appear at Worcester Crown Court on 28 August.
Additional reporting by PA