Why? Because the mention of pork offends Muslims.
From today's International Business Times:
"The move was revealed during a discussion on free speech during BBC Radio 4's Today programme in the wake of the attack on French satirical magazine Charlie Hedbo and its decision to use an image of the Prophet Mohammed on the cover of its latest issue.
Presenter Jim Naughtie said: "I've got a letter here that was sent out by OUP to an author doing something for young people.
"Among the things prohibited in the text that was commissioned by OUP was the following: Pigs plus sausages, or anything else which could be perceived as pork."
An OUP spokesman added, An OUP spokesperson said: "Our materials are sold in nearly 200 countries, and as such, and without compromising our commitment in any way, we encourage some authors of educational materials respectfully to consider cultural differences and sensitivities.
Read the whole thing here: http://www.ibtimes.co.uk/oxford-university-press-bans-mention-pork-pigs-books-avoid-offending-muslims-jews-1483378.