The victims, who took the 'prashad' last night, were admitted to the civil hospital as well as private hospitals, while four of them were referred to Guru Nanak Dev Hospital in Amritsar after their condition turned critical.
The deceased was one-and-a-half-year-old Baljit Singh, a resident of Guru Nanak Nagar. The other children who fell ill also belonged to the same locality, police said.
Priest Paramjit Singh, who distributed the 'prashad' after performing the 'Rehras Path', was taken into custody, they added.
A Health department team has collected the sample of the 'prashad' and sent it to the laboratory, police said.
Jaspal Singh, the father of the deceased child, said both of his sons started feeling uncomfortable after reaching home from the gurdwara.
While his younger son Baljit died, the condition of the elder son, Abhijit Singh, was stable, he added.