Food and beverages are often processed and packaged before use. Food contact plastic materials are all plastic materials that get in contact with food, beverages, and drinks during processing and manufacture, packaging, transportation, or use. It includes contact with plastic parts of machinery during food production.
Materials and articles such as plastics that can have contact with food and drinks must fulfill all legislative attributes laid down by the FDA on the physical and chemical safety of the material. plastic parts necessary for food packaging must be produced according to Good Manufacturing Practices (GMPs).
This will ensure that its constituents do not migrate into foods and beverages in quantities harmful to the lives of humans, or result in a genetic change in humans. Plastic has several advantages as a food contact material. Because of its fluidlike and moldable nature, it can be made into several sheets for various designs. Also, plastics are lightweight, cheap, and chemically inactive with a wide range of physical and optical properties.
Types of Food Contact Plastic Materials
As stated earlier, the type of plastic needed for food packaging must be an approved type of plastic to ensure product quality. All plastics intended to have contact with consumable products must adhere to Food and Drug Administration (FDA) regulations to ensure the product is safe for consumers.
There are several types of plastics, and some made it to the FDA-approved material list for food packaging. The following are the FDA-approved plastics that are generally safe for food packaging.
Polyethylene Terephthalate (PET)
PET is clear, tough, and biodegradable plastic. It has excellent distinctive properties such as its recyclability, non-toxic, unbreakable, chemical resistance, and gas/moisture barrier properties.
It is often used to produce disposable containers for liquids, soft drinks, and food such as detergents, salad, butter, different kinds of juice, cosmetics, etc. Unlike several other plastics, both un-recycled and recycled PET plastic is FDA-approved and safe for packaging food.
Propylene is a plastic polymer obtained from propylene monomers. It has low oxygen barrier quality, more reason it is used to produce packaging material for products without specific oxygen barrier such as yogurt, ketchup, soup, etc. It is microwave safe, implying it will not react with the product at a slightly high temperature, and it is heat resistant.
In addition, factories use Polypropylene made packaging to store strong acids, bases, and solvents. It is considered safe for all products provided no harmful product is found in the packaged food, drink, or beverage.
High-Density Propylene (HDPE)
HPDE is a clear, strong, and stiff petroleum product, giving rise to a heat-resistant food packaging material. It has some barrier characteristics which can be improved by the addition of polyamide (PA) or other additives to increase its gas barrier characteristics. It is assumed to have no health risk because of the absence of harmful Phthalate.
Worldwide, polyethylene is the most used plastic, opaque plastics for milk, juice, and water bottles are made with HDPE. It is used for beverage bottles, cereal box liners, and thicker food storage containers. FDA often contemplates the use of recycled HPDE-made food packs because it sometimes becomes unsafe to consumers after recycling.
Low-Density Propylene (LDPE)
LDPE is similar to HDPE, but more flexible and softer than HDPE because its polymer strands are interlinked and loosely organized. Its flexibility makes it perfect for the production of squeezable bottles, plastic wraps, grocery store bags, and more.
It is unreactive to microorganisms, chemically inactive, and does not release toxic substances into products stored with LDPE-made food containers at a wide temperature range. However, recycled plastic is unsafe for packaging consumable goods.
Polycarbonate plastics contain bisphenol A (BPA), which can be released into foods, drinks, and beverages stored in the container. However, the Food and Drug Administration (FDA) has approved Polycarbonate plastics as food contact plastic material.
Studies show that the BPA content of the plastic is very low and it poses less risk on human physical health. It is mostly used as a replacement material for glass in articles like refillable water bottles and sterilizable bottles, plastic dinnerware, and cutleries.
Food Contact Plastic Products Manufacturing
The following methods are probable methods of manufacturing food contact plastics using the previously discussed plastic materials.
Custom injection molding is the most widely used process of plastic manufacturing. It is similar to the extrusion molding process but differs in the method used to fill the molds with plastics. It is an important method for mass production of any plastic object ranging from small kitchen cutleries to large articles.
The process involves melting the polymer in granule form in the heating barrel of the injection machine. The melted granule is then forced out to fill the mold which can be the component of the intended item or the whole item. The viscous nature of the melted material causes the process to be carried out at high pressure.
Blow molding is the most varied of all plastic molding processes. Essentially, it produces hollow objects. Firstly, the raw material needed for the production of the hollow object is melted, after which it is formed into a parison.
Next, the plastic parison is placed on the top of the preformed hollow mold. Finally, compressed air is blown down onto the placed warm plastic parison, forcing the material to inward into the mold cavity thereby across the interior wall of the mold.
Vacuum molding is a common manufacturing process for the production of complex plastic shapes in thermoplastic sheeting. It is the opposite of blow molding in the process of production.
It involves sucking air out of the melted plastic parison, so it is forced into the mold by atmospheric pressure. It is used in the production of a certain range of plastic packaging materials such as the inner of chocolate boxes, etc.
Molded plastic parts are one of the most important packaging materials for food products. However, not all plastic materials are fit for food packaging. Only those food contact plastic materials approved by the FDA should be used to ensure safety.