Shelf Life of Food Products
Shelf life encompasses several facets of food quality including safety, nutritional value and sensory properties. Shelf life affects food quality, which in turn influences the consumer's buying decisions.
For many food companies, the ability of a food to retain its overall quality from the processing line, through distribution and marketing, and finally to the consumer, is the result of intensive studies to predict the "life" of a food.
Shelf life is the time frame over which a food product can be relied upon to retain its quality characteristics.
Intrinsic Parameters
Certain factors that are a part of the food's system cannot be controlled. The intrinsic factors inherent within food include pH, moisture content, water activity, nutrient content, antimicrobial agents, biological structures and oxidation/reduction potential.
Extrinsic Parameters
Unlike intrinsic parameters, extrinsic parameters can be controlled or changed to influence a product's shelf life. These factors include temperature, time, relative humidity, presence of gases, physical stress, and other environmental parameters.
Types of Deterioration
Physical deterioration associated with aging is evident by signs such as color fading, moisture changes and alterations in sensory properties including aroma and textural changes.
Microbial deterioration occurs when spoilage microorganisms survive processing treatments and cause deterioration via multiplication and propagation. Microorganisms also can produce off-flavors and slime.
Chemical deterioration often involves oxidative and hydrolytic reactions. Oxidative rancidity occurs when a fat (especially a highly unsaturated one) is attacked by oxygen, while hydrolytic rancidity involves enzymatic reactions.
Biological deterioration involves contamination of food products via birds, rodents or insects. These not only devour the food supply but transmit disease; hence, this type of deterioration may lead to microbial problems.
Shelf-Life Dating
Because consumers feel they have the right to know about the product and its shelf life, various dating systems have been implemented in order to provide the consumer with information deemed necessary to purchase food items. The purpose of dating is to inform the consumer about the shelf life of the product.
Many different types of dating may appear on the label of various food products. Thus, shelf-life dating can be evident in several ways.
- Pack date - the date on which the food was manufactured.
- Display dating - the date the food was placed on the store shelf.
- Sell by/pull date - the date the food must be sold or removed from the shelf.
- Best if used by dating - the date of the maximum quality of the product.
- Expiration date/use by date - the date the food must be consumed or discarded.