Food packaging lies at the very heart of the modern food industry and very few foods are sold unpackaged. Good packaging prevents waste and ensures that the food retains its desired quality throughout its shelf life. Despite its importance and the key role that packaging plays, it is often regarded as, at best, somewhat superfluous, and, at worst, a serious waste of resources and an environmental menace. Such views arise because, by the time most consumers come into contact with a package, its job, in many cases, is almost over. However, if the world is ever going to be able to feed 9 billion people, then the quality and quantity of food packaging is going to have to increase considerably.Get more news about Food Packaging,you can vist our website!
While food packaging is an integral component of food industry and helps to store food and beverages in hygienic manner, it can at times be a cause of concern for food safety. Some packaging materials such as certain types of plastic, polythenes, and styrofoam can release toxins when they are heated and can be dangerous to consumers. Packaging materials which are irradiated (along with food) can transfer unsafe nonfood substances into the food. Food packaging makes use of a variety of substances, including dyes for printing colorful labels, and glues and adhesives for keeping packaging closed. In order to protect consumers effectively, the relevant authority individually certifies each of these food packaging materials subjecting them to rigorous testing protocols.
Most materials used for packaging foods belong to the following classes: metals, glass, paper and polymers. Some packaging media consist of a combination of two or more materials of the classes listed above. Enameled (lacquered) metal and laminates formed by binding together layers of polymer, paper and aluminum foil are common examples of such composite materials.
The chemical composition and physical properties of packaging materials determine their ability to fulfill the various functions expected from the package. The most important properties to be considered in this context are transport properties, optical properties, mechanical properties and chemical reactivity.
Metal containers offer the advantage of superior mechanical strength, impermeability to mass transfer and to light, good thermal conductivity, and resistance to relatively high temperature. The latter two properties make metal packages particularly suitable for in-package thermal processing (see Section 18.2).
Tinplate, the first material used to make metal cans and canisters, consists of a thin sheet of steel, coated with tin. The purpose of the tin coat is to reduce the risk of corrosion. The quantity of steel plate is traditionally expressed in “base box” (bb). One base box is equivalent to 112 sheets, measuring 0.356×0.508 m each, and weighs approximately 20–60 kg, depending on the thickness of the sheets (Hanlon et al., 1998). In the past 50 years or so, advanced metallurgical processes have led to the production of steel plate with improved mechanical properties but with strongly reduced thickness. The thickness of the tin coating is quoted in nominal units of pounds per base box (lb/bb). The traditional method for coating the steel plates with tin, the “hot dip” method, has now been replaced by a process of electrolytic deposition. The electrolytic process of tinplating forms a more uniform tin coat with much less tin per unit area. Thus, both the thickness of the base plate and the weight of the tin coating per unit area of tinplate for cans have been reduced considerably, resulting in the production of lighter and less expensive cans with improved performance. For a review of processes for the production and improvement of tinplate, see Robertson (2005).
In some cases, the protection provided by tin is not sufficient for the prevention of internal or external corrosion of the can. Where the can is to face particularly severe corrosive conditions, a protective layer of polymeric lacquer or enamel is applied to the tin.