Answer:
Although it will be permissible for your friend to continue this job, however, if your friend can find another job, it will be better for him to leave this job, as according to the view of some jurists, this job is not be permissible.
The ruling mentioned above is applicable only if the factory belongs to a non-Muslim. If the factory belongs to a Muslim then it will not be permissible to work there at all. This is because ham and other haram food cannot be sold by a Muslim; and if a Muslim does sell haram food, the money that he makes from it will be haram. And if a Muslim employee is given this money as his income, it will not be permissible for him to take it, as it is haram money. On the other hand, for a non-Muslim it is permissible to sell ham and other food which the non-Muslims consider permissible (although haram in Islam) and to make money from it. And if a Muslim employee is given this money as his income, it will be permissible for him to take it. [1]
Mufti Faizal Riza
25/9/2011