Let Them Eat Plastic
Although it's been an issue of concern for many years in the scientific community, the mainstream media is only just catching up with the fact that plastics and food may not mix.
In May 1999, Bessie Berry of the US Food and Drug Administration's Food Safety Inspection Service (FSIS) got a lot of press warning that plastic and foam food containers were designed for one-time only use and had never been tested for reuse.
Almost everyone who has reheated food in a microwave has used an old margarine tub or similar container. A lot of people reheat coffee in styrofoam cups. The message from FSIS was straightforward: Don't.
If you do, the food you're heating can be contaminated with chemicals in the plastic. Nor should you cover food on a plate with plastic wrap, as this can also leach chemicals into your food.
There were only two things wrong with Ms. Berry's warning: she didn't explain why consumers should be worried and she probably didn't go far enough.
Chemical leaches
The thing many people don't realise about plastic is that it's not a stable thing. All plastics are made up of many chemicals. Some of these chemicals give it strength, some make it flexible, some are there to stabilise it, binding the other chemicals together and keeping them from breaking apart.
Unfortunately, they do break apart. If you've bought a PVC (vinyl) shower curtain and, when you hung it up, felt as if you were being gassed, you were. Chemicals in that plastic were gassing out of the product.
So it isn't all that surprising to discover that, if you heat this highly unstable product, chemicals can leach out of it and into anything it touches.
Chemicals called phthalates hit the news in 1998 when Health Canada warned parents to avoid purchasing soft PVC toys for kids under three, as phthalates could leach into children's saliva if they sucked on the toys.
Phthalates are only one of many chemicals identified as endocrine disrupters. These synthetic substances can interfere with growth, development, reproduction, immune system functions and intellect in fish, birds, reptiles, amphibians and mammals.
Some chemicals in plastic are known to be bad news, some are suspected of being bad news, and others are still waiting to be identified (usually by accident) as bad news.
Accidental Discovery
One such discovery was made by Tufts University scientists Ana Soto and Carlos Sonneschein. They were investigating the role of natural estrogen in breast cancer cell proliferation. When cells began proliferating all by themselves, Soto and Sonneschein discovered the cause was the plastic trays in which the cells were stored. The manufacturer had changed the formula of the plastic, but refused to tell them what the addition was, as this was a "trade secret". They went back to the lab, broke the plastic down themselves and discovered the culprit was a chemical called nonylphenol, widely used in plastics, pesticides, detergents, and shampoos. Until that point no one suspected nonylphenols were capable of mimicking natural estrogen.
Back to food: we know that another endocrine disrupter, bisphenol A, a breakdown product of the polycarbonate plastic used to line food cans, can leach into the food in those cans.
And, while you're chewing on that, here's another discovery Dr Soto has made: bisphenol A can also leach into the saliva of children from those polycarbonate plastic tooth sealants dentists are currently promoting.
Where's The Beef?
Unlike fashion editors, many synthetic chemicals, including endocrine disrupters, like fat. They seek it out.
So, again, it wasn't surprising when scientists at Consumers' Union analysed 19 samples of cheese sold in plastic wrap and discovered sometimes dangerously high levels of some chemicals in the plastic had migrated into the cheese.
One of these chemicals, DEHA (di-(2-ethylhexyl)adipate) had been identified as a concern in Europe. In the UK manufacturers substituted DEHA in plastic wrap with polymerised plasticisers more than 10 years ago, largely eliminating the problem.
Other studies show that chemicals in plastic wrap can migrate into beef.
As the chemical industry is quick to point out, we're not sure how much of a problem, if any, these residues in our food may cause. We certainly know there could be a problem.
Microwaving food in plastic is definitely a bad idea. Shaving the top layer of cheese which has been in contact with plastic is probably a good idea. How far should you go?
Ana Soto won't let her children's food come into contact with plastic even in the fridge. As a scientist she admits she may be erring on the side of caution. As a mother, she's not prepared to take a chance.
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