It doesn't (expressly)... Also, it doesn't expressly say that any of these households even possessed any infants (but I believe that the presence of infants, older children and slaves would be a fair and proper assumption).
I would note that for the Abrahamic covenant, the ritual for infants is expressly stated....and I think that it is fair to conclude that for the New Covenant the ritual for infants is implicitly denied because of the emphasis on belief. An interesting fact is that "we cannot give the name of anyone before the fourth century not in an emergency situation who was baptized as an infant"... see E Ferguson, BAPTISM IN THE EARLY CHURCH p. 379 quoting Wright. So it seems that in the very early church infant baptism wasn't the norm, but also wasn't prohibited (and so it was done for infants who were about to die)