There is no way to tell, as stated in the article.
"Of the more than 200 black plastic products Liu bought at retail stores for her study, hardly any were labeled as being made from recycled materials, she said. Consumers have no way to tell which black plastics might be recycled e-waste and which aren’t. “It’s just a minefield, really,” Turner said."
I was under the impression that labelling something as "recycled" was a value add, and it would be done where possible. I suppose that is not actually the case.
The article is nonsense. Only engineering plastics carry UL94 ratings (and if it's got flame retardants in it, it's got a UL94 rating... otherwise no one would go to the expense!) and there are just not a lot of engineering plastics in the waste stream compared to consumer single-use plastics.
The point is that these plastics with flame retardants would go to recycling, and would eventually find their way into cooking utensils made of recycled plastics. Nobody adds the flame retardant there intentionally, but nobody removes the flame retardants from the recycled mass either, at least not in places where plastic recycling is normally done (not the richest countries).
Frankly, the idea of using recycled plastic with no control for its origin for cooking utensils looks weird to me. OTOH it should look like a great opportunity to cut costs, and shoppers very often try to save that last cent as a matter of principle and sport, so...
Coffee machines from reputable makers should be safe, I think.
"To investigate the extent to which kitchen utensils are contaminated with BFRs and the potential for resultant human exposure, we collected 96 plastic kitchen utensils and screened for Br content using a hand-held X-ray fluorescence (XRF) spectrometer. Only 3 out of 27 utensils purchased after 2011 contained detectable concentrations of Br (≥ 3 μg/g). In contrast, Br was detected in 31 out of the 69 utensils purchased before 2011."
Let me emphasize: Only 3 out of 27 utensils purchased after 2011 contained detectable concentrations of Br.
Further vital information: "Simulated cooking experiments were conducted to investigate BFR transfer from selected utensils (n = 10) to hot cooking oil, with considerable transfer (20% on average) observed."
Fine, I don't cook with hot oil. I don't melt my utensils when cooking, I don't damage them at all. I see the reason for concern, but for my cooking styles this really doesn't affect me.
I am bit weirded by using recycled plastics for anything interact with regularly with my hands for example. Also stuff that get heated. Sure it has places like furniture, decking and so on where contamination doesn't really matter. But what about something like re-usable cup for hot beverages or disposable cutlery?
