Sheikh Hânî al-Jubayr, judge at the Jeddah Supreme Court
A Muslim is prohibited from preparing or serving any meals that contain pork, or being involved in the taking of orders and payment for such meals.
The evidence for this is the hadîth of Jâbir that the Prophet (peace be upon him) said: “Allah and His Messenger have prohibited the sale of alcoholic beverages, carrion, pork, and idols.” [Sahîh al-Bukhârî (2236) and Sahîh Muslim (1581)]
This prohibition is general. Therefore selling these things is prohibited, regardless of whether the customer is a Muslim or a non-Muslim.
As for working as a cleaner for a restaurant that sells such things as a part of its menu, there is no prohibition against this.
And Allah knows best.
Source: Islam Today