Lyophilization is a dehydration process in which frozen product is held under vacuum so that ice sublimes directly into vapour, preserving colour, structure and heat-sensitive nutrients while yielding a shelf-stable, easily rehydrated product.
In trade practice
Suppliers document chamber temperature, vacuum level and cycle duration in batch records, which buyers or third-party auditors review at qualification. QA teams verify moisture content and water activity on finished product to confirm shelf stability. A common mistake is accepting lyophilization as a blanket quality claim without checking those batch parameters or running rehydration tests. Certificates of analysis should state moisture and water activity alongside microbiological results.
In a specification
A product specification typically states the drying method as lyophilization and sets maximum moisture content and water activity limits, often alongside colour and rehydration ratio requirements.