Smell. there is a horriable smell in my zanussi intergrated fridge freezer only in the fridge part

Question

there is a horriable smell in my zanussi intergrated fridge freezer only in the fridge part even after scrubbing clean but when i close the door and open again after 5 mins its back

My fridge smells like rotting vegetation. I have emptied it and scrubbed it out but 5 minutes later the smell is back