PLASTICS versus FOOD CONTAMINATION

THE use of plastics materials for food processing environments has obvious advantages associated with the (by and large) non‐toxic nature of these materials and their resistance to chemical and biological degradation. To obtain high strength and rigidity as additional properties, plastics‐clad steel sheet is often used for construction in food operations. One such material is Stelvetite, a pvc‐clad steel seen here (Fig. 1) in use as a cladding for the walls of a brewery fermenting room and also as a lining for the fermenting vessels. Here the primary consideration was prevention of the growth of wild yeasts, which previously (Fig. 2) had grown in wall crevices, including the cracks in glazed surfaces, and had thus threatened the purity of the fermenting process. However, another major consideration was the elimination of corrosion and degradation due to condensation in the wet atmosphere of the fermenting room. Stelvetite is also employed extensively for the exterior and interior panelling of cold stores for poultry, meat and provisions, where the material has to process a decorative finish which does not need painting and can undergo fabrication without damage to this finish. For the more corrosive food applications such as refrigerated shopfittings, Stelvetite is produced on a hot‐dipped galvanized (Galvatite) base for increased protection.