Plastic-Rice! How to Test?

The trending news is that Supreme Court of India has considered the petition regarding fake  plastic-rice and will have a hearing after few weeks. Can we wait till then and keep on consuming rice peacefully as before. As it has already reached India and is getting mixed with normal rice I couldn’t wait for the court’s decision. I planed to go ahead with testing of my own.

I have done little bit of Chemistry during college and can safely do some tests for  confirming plastics in the rice and other stuffs. Its difficult but some of the chemicals can be procured and plastics can be tested.  Most of the homemakers, mothers who are  not into chemistry, and want  their  kids’ food to be free of toxins and chemicals, what will they do? There was only one testing available on the web and that was cooking the rice to get the thick layer of  starch and plastic on top. This method works fine if all the rice is of plastic but if real rice is mixed with the plastic one the signature thick layer will not be easy to detect.

I started searching for home tests for plastics. Got some good tips too but without knowing the plastic (polyethylene, PVC, Styrofoam, nylon, PET) it’s difficult to select tests and most of the chemicals are not available at home.  Some of the tests are listed below.

-Acetone melts Styrofoam (Acetone is available in nail polish removers as well as chemists shop). Styrofoam is made of polystyrene inflated with a lot of air. So acetone will melt anything made of polystyrene.

-Thermoplastics like Polyurethane which we see as polyurethane foam (in seat cushions for example) is a difficult plastic being stable at high temperatures too. Chemicals like tetrahydrofuran (THF) dissolves it but THF is not found in homes and is dangerous chemical to use. THF also dissolves PVC.

-Alcohols, such as ethanol (liquors) and isopropanol, cause about 15 to 30% swelling and acetone,act as partial solvents. So if we put rice in a test tube of alcohol they should swell up 30% if they are made of Polyurethane and in a test tube of acetone they should dissolve partially and decrease in size. Difficult but still doable test.

 -Then comes PET (polyethylene terephthalate), the plastic used in soda bottles. This is really hard nut to crack as most of the solvents have no effect on it and the ones used are extremely dangerous. Similarly some other plastics too are resistant to most of the common solvents.

It seemed that most of the plastics can not be tested at home then searching web I came across a thread in a forum of homemakers which was discussing how to dissolve melted plastic from stove and it suddenly clicked that instead of all these painful dangerous, chemical methods we can try a simple test of burning rice in flames to see if any changes occur.

Real rice will char and not give any fumes or become watery or clump together. Different plastic behave differently when burned. But one common factor is that they will all burn and melt. I tried burning rice and it just turned black with out melting. Lucky! I still have good rice. Try and send me your inputs if you see  any melting dripping from your rice . Some plastics’ flames tests are mentioned below.

PET melts with [1] yellow and slow flame, does not ignite, self-extinguishes little or no smoke, plastic drips and does not char.

-We  all have  seen how a polythene bag melts in fire with smoke and smell.

-Styrofoam ignites and plastic drips with extremely dangerously fumes.

Another possible way to test is to put rice in really really hot oil [2]. An oil whose smoking point is above 200C like Canola oil. I think coconut oil will also do as its smoking point is  about 170C. I hot oil  plastic should become gooey, melt or stick together or stick at the bottom of pan. This video should help[3].

Do test some grains of the rice you buy before using but please perform these burning tests outside in fresh air as we don’t know which plastics are used. There are lots of different plastics, and they will give off lots of different vapours when they are burned. It could be just a simple hydrocarbon, or it could contain cyanides, or PCB’s, or lots of other substances. Volatiles given off from plastics in house fires are a major cause of death.”




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