1.   Cops went from shop to shop to check whether potentially contaminated products had been taken off the shelves.

2.   Cops went from shop to shop to check whether potentially contaminated poultry products had been taken off the shelves.

3.   Officers went from shop to shop checking that potentially contaminated products had been taken off the shelves.

4.   Police went from shop to shop to check whether potentially contaminated poultry products had been taken off the shelves.