Definition of expiry date

The term "expiry date" is used to indicate the period after which a product or substance is no longer safe or effective to use. This date is determined by the manufacturer based on factors such as chemical stability, microbial growth, and degradation over time. The origin of the word "expiry" can be traced back to the mid-19th century when the British Standard Time was introduced, and Railway Time began to be used for the timetables. This concept led to the idea of "expiry" in reference to the validity of certain documents and permits, indicating that the usage of such documents would expire at a specific date. However, the use of "expiry" in reference to products and substances can be attributed to the rise of pharmaceutical and food industries. As these industries began to mass-produce items, the need to ensure the quality and safety of these products over a specific period became increasingly necessary. The establishment of expiration dates provided a simple, consistent way for consumers to be informed of when a product became unsafe to use, and the manufacturer could regulate the quality of these goods. In summary, the word "expiry" in the context of product safety, originated from the idea of expirability in documents and permits, and its use in the context of food and pharmaceuticals became more prevalent due to the need for safety and quality control in mass-produced goods.