Jennifer Keeley, 45, was visiting her daughter, Sarah, in Horncastle, Lincolnshire, when the family's Welsh collie jumped up and bit off the tip of her nose.
Constable Brian Kettleborough, 33, who answered the emergency call, said: 'I went into the kitchen and saw her nose on the working top. It was quite a shock.'
He asked Sarah, 22, whether she had anything frozen and was told there were frozen peas in the freezer. 'We opened the bag and she popped the nose inside.'
PC Kettleborough then drove the severed nose 22 miles to Lincoln County hospital, where Mrs Keeley had been taken.
Mrs Keeley, of Horncastle, was later transferred to a specialist microsurgery unit in Leicester Royal Infirmary. It was not clear whether surgeons were planning to sew the severed nose back. The dog was put down.