Jews who are kosher do not eat pork or shellfish for the following reason:
In the Bible, G‑d lists two requirements for an animal to be kosher (fit to eat) for a Jew: Animals must chew their cud and have split hooves. Pigs do have split hooves but do not chew their cud, so we cannot eat pig meat and its derivatives. In the seafood department, we may only eat fish that have both fins and scales. (Source)
Yet Jews whose job it is to check people out at a grocery store would likely not 'hold up' management to have a replacement employee handle the food as Muslim employees have done in England.
And, if the Jewish employees actually tried, management would likely fire them for making unreasonable demands!
But in a politically correct world where fear of retribution supersedes common sense, here is a story about the grocery chain Marks and Spencer in England and Ireland:
Marks & Spencer is facing a boycott from hundreds of customers furious at the store’s decision to allow Muslim staff to refuse to serve customers buying alcohol or pork products.
The policy was revealed after customers trying to buy pork or alcohol from a Muslim shop assistant in central London were told they would have to use another till because of the cashier's religion.
The chain has admitted, however, that it has breached its own internal policy - by forcing its staff to choose between their beliefs and their responsibilties to the supermarket.
A spokesperson for M&S said that it works closely with employees with specific beliefs that restrict what food or drink they can handle, but on this occasion it had to “regret” that it had not followed its own guidelines.
“Where we have an employee whose religious beliefs restrict food or drink they can handle, we work closely with our member of staff to place them in suitable role, such as in our clothing department or bakery in foods. (Source)