please donot get confused between ESI/PF and category of employees.
There are number of category of employees like Casual,temporary,probationer,permanent,fixed term,Badli and donot mix it with applicability of ESI/PF.
ESI and Pf acts are applicable to all category of employees from day one.
From India, Delhi
Probationer is also treat as like Company Employee in the Organizations.
Only separation in between Apprentice ship employee & Company employee on this matter.
From India, Faridabad