How to know when food grade plastic has melted?
I just received a super hot delivery of soup in a polypropylene container (the plastic symbol on the bottom is a 5). I noticed the lid was very pliable in comparison to the rest of the container to the point I could easily bend it and cause the surface to warp by poking it with my finger. After lifting my finger it would bounce back somewhat, but retain some of that warping. As it cools it's returning to it's original shape and becoming harder to manipulate.
I'm wondering if this implies melting/leeching has occurred and if I should just return the soup to be safe.
Best Answer
Plastic is an amorphous solid. This means that it doesn't have a sharp melting point like water, but it goes through a state where it is softer and softer, until it turns liquid.
So yes, the plastic was in this state when you touched it. If you want to call this transitional state "melted", then it was melted. Unless you prefer to call it "softened". Everyday language is blurry enough to permit both.
If you are worried about melted plastic actually mixing throughout the soup, like vinegar would mix if you were to add it, that's not what happened.
As to "leeching", this is not well defined and not usually covered by food safety rules. Plastics do tend to have overheating restrictions over which they char, but as for "leeching", the only regulated one I know of would be melamine, and I'm pretty sure that's not what your box was made of. So throwing it out or not depends on your personal feelings about leeching.
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Quick Answer about "How to know when food grade plastic has melted?"
Plastic is an amorphous solid. This means that it doesn't have a sharp melting point like water, but it goes through a state where it is softer and softer, until it turns liquid. So yes, the plastic was in this state when you touched it. If you want to call this transitional state "melted", then it was melted.Can you eat food if plastic has melted?
Back on the other side of the wrap, the American Plastics Council cites a former FDA supervisory chemist, Dr. Charles Breder: "If you were to accidentally eat food containing melted plastic, you wouldn't suffer any harmful effects to your health, but your food probably wouldn't taste too appetizing."What temperature does food grade plastic melt?
High-density and low-density polyethylenes -- HDPE and LDPE, or recyclables 2 and 4 -- melt at 130 degrees Celsius (266 degrees Fahrenheit) and 120 degrees Celsius (248 degrees Fahrenheit), respectively, according to Dynalab Corp.Is plastic toxic when heated?
"The vast majority of plastics used in food wraps and packaging containers do not contain the chemical constitutes that can form dioxins, which are a family of compounds produced by combustion at temperatures greater than 700 degrees Fahrenheit."Is it safe to use oven after plastic melted?
The short answer is probably not. While the jury is still out on this one, some organizations do point out the potential dangers of fumes from burning plastics. The USDA points out that any food permeated by any toxic fumes should be thrown out.Plastics that are safe to reuse in your home
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Answer 2
Melt is not necessarily leech. It could melt and have two insoluble liquids and not have any leeching. And then again might get some leeching from liquid plastic that would not happen from solid. If it came back to form then it likely did not melt. The melting point of polypropylene is greater than the boiling point of water. WIKI
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