Food Safety Report: Ocado Head Office, Hatfield, UK 1 year ago • details 11 Comments Comment Suspected food poisoning. Symptoms: Vomiting, Fever Suspected source: Iceberg lettuce bagged m&s Onset: Less than 4 hours Duration: 4 to 12 hours Sick: Me. Delivered in Surrey by Ocado. Marks & Spencer iceberg bagged lettuce