All foods spoil with time. Have you ever wondered how long a shelf life could a product have? In fact, there is considerable variation in spoilage rates, some of the factors that may determine the shelf life of a product are discussed below.
Microbial Growth
The growth of some bacteria, yeasts and moulds in food may lead to either food spoilage or food poisoning. The time taken for microorganisms to affect foods will depend on their levels in the food when it is produced, as well as any further contamination the food may have during processing and other handling. The temperature and time of storage, as well as the type of ingredients, are also important factors. Moist foods will usually spoil faster than dry foods.
Non-microbial Spoilage
There are many other ways in which quality and nutrients can be lost. They may not necessarily result in the product being harmful but can mean that it is no longer of an acceptable standard. For example, moisture gain/loss and chemical change can result in loss of nutrients, browning or rancidity.
Advice to the Trade
Shelf life is a guide for the consumer of the period of time that food can be kept before it starts to deteriorate, provided that the stated storage conditions, if any, on the package have been followed. Traders, particularly the manufacturers who are the ones more familiar with the nature of and ingredients used in the final product, have the responsibility to set the appropriate durability indication i.e. either a "best before" or "use by" date, together with the storage instructions required to achieve the stated shelf life. They should consult with technical experts before giving a date mark to indicate the shelf life of food.
Advice to the Public
Members of the public should take note of the expiry date of the food items before purchase or consumption, follow manufacturer's instruction for proper storage, and not to purchase or consume food if the packaging is damaged as it may have been contaminated or deteriorated even if it is still within the expiry date.