Plastic Covering

Plastic covering serves as a barrier against oxygen, moisture, acids, bases, solvents, and odors and can keep foods, both raw and cooked, fresh longer. One of the first plastics to be used to protect food was polyvinylidene chloride (PVDC), which came to the attention of researchers at Dow Chemical Company in 1933 when Ralph Wiley, a laboratory worker, accidentally found the substance in a vial that he could not scrub clean. Researchers made the PVDC into a greasy film, which Dow named Saran. Initially used to protect fighter jets from salty sea spray and as a stain repellent for car upholstery, Saran was cleared for use in food packaging after World War II. Saran films are best known in the form of Saran Wrap film, the first cling wrap designed for household (1953) and commercial use (1949), introduced by the Dow Chemical Company. Saran Wrap brand plastic film is marketed by chemical products giant S. C. Johnson Company.