A raw material is any substance used to manufacture a product, and in food production the term covers every ingredient and processing aid that enters the factory: flour and eggs for cakes, milk for cheese, spices, oils, water, and packaging that contacts food. Because the safety of the finished product can never exceed the safety of what went into it, commercial food businesses apply strict hygiene and quality controls to raw materials. Deliveries are checked against specifications, stored under correct conditions, and used in rotation, while suppliers are approved and audited. Traceability records link each batch of finished product back to its raw-material lots, so that if contamination is found, the source can be identified and affected stock isolated quickly.