Historically, plastic was firstly invented by Alexander Parkes who publicly demonstrated it at the 1862 Great International Exhibition in London. The first material was called Parkesine and it was an organic material derived from cellulose that once heated could be molded, and retained its shape when cooled.
Alexander Parkes was born in 1813 in Birmingham, England growing up with a number of extremely interesting ideologies and inventions. Parkes worked for some time in the manufacturing of natural rubber, when great steps were made with the discovery of vulcanization and the first machines. From this finding arose his interest in other substances which could give similar results to those of rubber in certain uses for which there was a constantly increasing industrial demand.
Hence, by studying cellulose nitrate, obtained in 1845 at Basle by C.F.Schönbein, Parkes developed a new material which could be used in a solid, plastic of fluid state, which was at times rigid like ivory, opaque, flexible, water-resistant, colourable and could be used for utensils and tools like metals, compression moulding, laminating. Parkes described his invention Parkesine in these words – patented in 1861 – in a publicity handout of 1862 at the Great London Exhibition, where, for the first time, examples appeared of that which we could justly call the original plastic material.
However nowadays most of the plastic materials are non-organic where mostly raw materials are from petroleum and natural gas. Plastic raw materials and products nowadays come from various countries of origin where most of us are unaware whether it is safe or unsafe to be used. In this article we focus more on plastic in food and beverage industry.
Polyethylene terephthalate (PET or PETE)
PET is used to make packaging (bottle or container) for example for soft drink, water, sports drink, ketchup, salad dressing bottles, peanut butter, pickle, je
lly and jam jars. You could identify it by looking at the bottom of the bottle or jars with recycling number 1 or with recycle logo number 1 as shown in the picture below. Bottles or jars made from PET are normally looks clear, colorless, flexible and not hard.
Although some study has found some negative impact of using PET bottles, however no accurate information could verify it correctly. Thus PET could be considered safe since from the day the study was published in 2007 until now no other proves are suspected to be unsafe or unhealthy.
Reference: Claim of PET to be Unsafe in 2007
According to a study by the Goethe University, Frankfurt in Germany drinking water from bottle made out of PET may prove to be dangerous to the health. They have stated that this type of plastic may contain estrogen-like compounds which may leach into the water and possibly create hazards to the health.
They were said to have discovered that certain compounds akin to the female sex hormone may leak into the water from the bottles made of polyethylene terephthalate plastic or PET.
In order to verify this claim the study investigators analyzed such bottled water through the use of genetically engineering yeast. It was believed that nine samples were taken from glass bottles, nine from PET plastic bottles and two from cardboard boxes.
The results were very surprising. Estrogen like compounds were detected in seven PET plastic bottles and both the cardboard boxes as against to just three of the glass bottles. The study investigators were astounded to discover such a high level of the female hormone-like compound in these water samples.
In order to further evaluate this criterion, the investigators conducted more tests on these waters. In order to verify whether the estrogen compounds were coming from the water itself, they replaced the water with a pure snail medium. Following which a particular type of snail, which is especially sensitive to estrogen compounds, was introduced in the water.
After a period of two months it was observed that the female snails living in the PET plastic bottles had double the amount of embryos in their body as against to the snails living in glass bottles. Thus, indicating that certain compounds may have leaked from the plastic into the water which may have played havoc with the reproductive system of the female snails.
Having said this they have concluded by stating that it may be too soon to accurately verify whether PET plastic bottles may be dangerous to human beings.
High density polyethylene (HDPE)
High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a polyethylene thermoplastic made from petroleum. It takes 1.75 kilograms of petroleum to make one kilogram of HDPE. The global market for HDPE is more than 30 million tons annually.
HDPE bottles or food container is normally use for milk, water, juice bottles, yogurt and margarine tubs, cereal box liners, and grocery, trash, and retail bags.
You could identify it by looking at the bottom of the bottle or containers with recycling number 2 or with recycle logo number 2 as shown in the picture above. Containers made from HDPE are normally looks half clear, harder and stronger than the PET.
Polyvinyl chloride (V or PVC)
PVC is a thermoplastic polymer and it is the third most widely produced plastic, after polyethylene and polypropylene. PVC production is expected to exceed 40 million tons annually. PVC was accidentally discovered at least twice in the 19th century, first in 1835 by Henri Victor Regnault of Paris, France and in 1872 by Eugen Baumann of Stuttgart, Germany. On both occasions the polymer appeared as a white solid inside flasks of vinyl chloride that had been left exposed to sunlight.
In the early 20th century the Russian chemist Ivan Ostromislensky and Fritz Klatte of the German chemical company Griesheim-Elektron both attempted to use PVC in commercial products, but difficulties in processing the rigid, sometimes brittle polymer blocked their efforts. Waldo Semon and the B.F. Goodrich Company developed a method in 1926 to plasticize PVC by blending it with various additives. The result was a more flexible and more easily processed material that soon achieved widespread commercial use.
For food and beverage applications, PVC is used to make most cling-wrapped meats, cheeses, and other foods sold in delicatessens and groceries are wrapped in PVC.
Identifying plastic made from PVC is regularly with printed of recycle logo number 3 as shown in the picture above.
Low-density polyethylene (LDPE)
LDPE is a thermoplastic made from petroleum and it was the first grade of polyethylene, produced in 1933 by Imperial Chemical Industries (ICI) of England using a high pressure process via free radical polymerization.
LDPE is widely used for producing various containers, dispensing bottles, wash bottles, tubing, plastic bags for computer components, and various molded laboratory equipment. However the most common use of LDPE is in plastic bags. Other products made from LDPE include:
- Trays and general purpose containers
- Corrosion-resistant work surfaces
- Parts that need to be weldable and machinable
- Parts that require flexibility, for which it serves very well
- Very soft and pliable parts
- Six pack rings
- Juice and milk cartons is made of liquid packaging board, a laminate of paperboard and LDPE (as the water-proof inner and outer layer), and often with of a layer of aluminum foil (thus becoming aseptic packaging).
- Parts of computer hardware, such as hard disk drives, screen cards, and optical disc drives
- Playground slides
- Plastic wraps
Identifying plastic made from LDPE is regularly with printed of recycle logo number 4 as shown in the picture above.
Propylene was first polymerized to a crystalline isotactic polymer by Giulio Natta of Italy as well as by the German chemist Karl Rehn in March 1954. This pioneering discovery led to large-scale commercial production of isotactic polypropylene from 1957 onwards. Syndiotactic polypropylene was also first synthesized by Giulio Natta and his coworkers.
For food and drink PP is generally use to produce some ketchup bottles, yogurt packaging and margarine tubs.
Identifying plastic made from PP is regularly with printed of recycle logo number 5 as shown in the picture above.
Polystyrene or PS, is an aromatic polymer made from the monomer styrene, a liquid hydrocarbon that is manufactured from petroleum by the chemical industry. Polystyrene is one of the most widely used plastics, the scale being several billion kilograms per year.
Polystyrene is a thermoplastic substance, which is in solid or glassy state at room temperature, but flows if heated above its glass transition temperature of about 100 °C i.e. for molding or extrusion, and becomes solid again when cooled. Pure solid polystyrene is a colorless, hard plastic with limited flexibility. It can be cast into molds with fine detail. Polystyrene can be transparent or can be made to take on various colors.
Polystyrene can be recycled, and has the number “6″ as its recycling symbol as shown in the picture above. The increasing oil prices have increased the value of polystyrene for recycling. No known microorganism has yet been shown to biodegrade polystyrene, and it is often abundant as a form of pollution in the outdoor environment, particularly along shores and waterways especially in its low density cellular form.
Other (usually polycarbonate)
Polycarbonates, known by the trademarked names Lexan, Makrolon, Makroclear and others, are a particular group of thermoplastic polymers. They are easily worked, molded, and thermoformed. Because of these properties, polycarbonates have so many applications. Polycarbonates do not have a unique plastic identification code and are identified as Other, 7.
Products which are produced using polycarbonate raw plastic are baby bottles, microwave ovenware, eating utensils and plastic coating for metal cans. Any product made of hard, clear plastic is probably made from polycarbonate unless the manufacturer specifically states that it’s BPA-free. One way to check is to look for the triangle stamp on or near the bottom: polycarbonate plastics should have the numeral 7 in the triangle, sometimes with the letters PC.
Bisphenol-a or BPA is a hormone disruptor which simulates the action of estrogen when tested in human breast cancer studies. Research founds that BPA can leach into food as product ages.
While most of the people focus is on products for children, including clear plastic bottles and canned infant formula, the chemical is also used in food-storage containers; some clear plastic pitchers used for filtered water, refillable water bottles and the lining of soft-drink and food.